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Laboratory assessment of the potential of Nigerian-grown Gmelina Arborea Roxb. for newsprint manufacture Iloabachie, Chris I. S. 1977

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LABORATORY ASSESSMENT OF THE POTENTIAL OF NIGERIAN-GROWN GMELINA ARBOREA ROXB. FOR NEWSPRINT MANUFACTURE  by CHRIS I . S . ILOABACHIE B.Sc.  ( H o n s ) , U n i v e r s i t y o f I b a d a n , 1974  A T H E S I S SUBMITTED I N P A R T I A L F U L F I L L M E N T OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF FORESTRY in THE FACULTY OF GRADUATE STUDIES in THE FACULTY OF FORESTRY (4 u n i t s ) We a c c e p t t h i s t h e s i s a s c o n f o r m i n g to the required standard  THE U N I V E R S I T Y OF B R I T I S H COLUMBIA A u g u s t , 1977 ©C.I.S.  Iloabachie  In p r e s e n t i n g t h i s  thesis  in p a r t i a l  f u l f i l m e n t of  the requirements  for  an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree that the L i b r a r y s h a l l I  f u r t h e r agree  for  scholarly  make i t  that permission  this  written  thesis  reference and study.  f o r e x t e n s i v e copying of  It  for financial  gain s h a l l  of  The U n i v e r s i t y o f B r i t i s h 2075 Wesbrook P l a c e V a n c o u v e r , Canada V6T 1W5  this  thesis  of my Department or  i s understood that copying or p u b l i c a t i o n  permission.  Department  for  purposes may be granted by the Head  by h i s r e p r e s e n t a t i v e s . of  freely available  Columbia  not be allowed without my  ABSTRACT E x t e n s i o n o f p u l p and paper  r a w m a t e r i a l b a s e by  i n c r e a s e d u t i l i z a t i o n o f h a r d w o o d s p e c i e s i s one r e a s o n a b l e approach  t o the s o l u t i o n o f the world f i b e r shortage  This i s p a r t i c u l a r l y mechanical  so i f mechanical  pulp w i t h adequate  a n d o p t i c a l p r o p e r t i e s c a n be p r o d u c e d  g r o w i n g hardwoods which  problem.  from  fast-  have n o t been used t o any g r e a t  e x t e n t i n t h e p a s t a s a raw m a t e r i a l . L a b o r a t o r y s t u d i e s r e p o r t e d i n t h i s t h e s i s were c a r r i e d out t o assess the response  o f Gmelina  a h a r d w o o d grown e x t e n s i v e l y i n N i g e r i a , ing.  a r b o r e a Roxb.,  t o mechanical  pulp-  I n t h i s w o r k , b o t h o p e n d i s c h a r g e and s i m u l a t e d t h e r m o -  mechanical  r e f i n e r groundwood p u l p s w e r e p r o d u c e d .  I n the  l a t t e r case, the e f f e c t of chemical pretreatment w i t h both sodium s u l f i t e  a n d s o d i u m h y d r o x i d e was a l s o e v a l u a t e d .  was f o u n d t h a t w h i l e o p e n d i s c h a r g e a n d s t a n d a r d mechanical  It  thermo-  treatments r e s u l t e d i n mechanical pulp with  i n f e r i o r p r o p e r t i e s , t h e treatment o f c h i p s o f Gmelina a r b o r e a Roxb. w i t h a 1% s o d i u m h y d r o x i d e s o l u t i o n a t 2 5 0 F D  (121°C) f o r 10 m i n u t e s  prior  r e s u l t e d i n a mechanical  t o open d i s c h a r g e  pulp having mechanical  refining and o p t i c a l  p r o p e r t i e s comparable t o and, i n c e r t a i n a s p e c t s , b e t t e r t h o s e o f s t o n e groundwood used  i  i n North American  than  newsprint.  The  behaviour of t h i s chemically pretreated r e f i n e r  p u l p from Gmelina investigated. furnish  i n a d m i x t u r e w i t h s o f t w o o d k r a f t was  I t was  handsheets  found t h a t the p r o p e r t i e s of newsprint  c o n t a i n i n g mixtures o f Gmelina  p u l p and West C o a s t s e m i - b l e a c h e d k r a f t a b l y w i t h those of handsheets  produced  newsprint f u r n i s h e s , thus i n d i c a t i n g c h e m i c a l l y p r e t r e a t e d Gmelina r e d u c e d amounts d f s o f t w o o d  (SBK)  mechanical  compared f a v o u r -  f r o m t y p i c a l West  Coast  the p o s s i b i l i t y of u s i n g  thermomechanical  pulp  (TMP) w i t h  SBK.  To c o v e r t h e s i t u a t i o n f o r a f u l l y a b r i e f s t u d y was  also  integrated  i n c l u d e d t o assess the response of  mill,  Gmelina  t o k r a f t c o o k i n g , and t o e v a l u a t e t h e b e h a v i o u r o f t h i s p u l p i n admixture w i t h Gmelina mechanical p u l p . k r a f t p u l p f r o m G m e l i n a was cally,  than North American  As e x p e c t e d ,  s i g n i f i c a n t l y weaker, mechanik r a f t p u l p s and  i t s deficiencies  were c l e a r l y e v i d e n t i n the p r o p e r t i e s o f mixed handsheets.  I t was  the  furnish  concluded, from t h i s p a r t o f the  study,  t h a t n e w s p r i n t c o n t a i n i n g b o t h i t s c h e m i c a l and i t s m e c h a n i c a l p u l p components from Gmelina would l a r g e p r o p o r t i o n s of Gmelina  require  c h e m i c a l p u l p and  a l i m i t i n g i n f l u e n c e on p a p e r machine speed and printing  excessively still  exert  subsequent  o p e r a t i o n s because of i t s s t r e n g t h d e f i c i e n c i e s .  TABLE OF CONTENTS Page ABSTRACT  i  TABLE OF CONTENTS  i  i  L I S T OF TABLES  i  v i  L I S T OF FIGURES  v i i  ACKNOWLEDGEMENTS  ix  Chapter I. II.  INTRODUCTION  .  1  LITERATURE SURVEY  4  General I n t r o d u c t i o n  4  S i l v i c u l t u r e , Plantation Establishment and G r o w t h  4  Wood a n d F i b e r P r o p e r t i e s  6  Previous Pulping Studies  8  Mechanical Pulping 1. S t o n e Groundwood (SGW) P r o c e s s ... 2. C h i p R e f i n e r M e c h a n i c a l P u l p i n g . . . a) Chip R e f i n e r Mechanical P u l p (RMP) b.) T h e r m o m e c h a n i c a l P r o c e s s (TMP). . c) S i g n i f i c a n c e o f Chip R e f i n e r Mechanical Pulping  18  Chipping  21  .  Chip Pretreatments 1. 2.  P r e t r e a t m e n t by Steaming Chemical Pretreatment  13 14 16 16 16  21 21 25  S i g n i f i c a n c e of F i b e r Length and Fiber Fractions  27  Pulp Blending  29 iii  iv Chapter III  Page EXPERIMENTAL WORK . .  32  Introduction  32  S o u r c e o f M a t e r i a l s and M a t e r i a l s S t o r a g e .  33  Mechanical  34  Pulping  Pulp Evaluation  35  1. L a t e n c y Removal 2. Debris Content 3. Freeness 4. Yield 5. F i b e r Length C l a s s i f i c a t i o n s Sulfate Pulping  35 36 36 37 38 39  ....  K a p p a Number o f S u l f a t e P u l p s . . . . Semi-Bleaching of S u l f a t e Pulp ... a) C h l o r i n a t i o n Stage b) E x t r a c t i o n Stage c) H y p o c h l o r i t e Stage  Handsheet M a k i n g and E v a l u a t i o n RESULTS AND  40 40 41 42 43 43  DISCUSSION  45  M e c h a n i c a l P u l p s from Gmelina  45  Yield  45  S p e c i f i c Energy Consumption  46  Debris Content  49  Mechanical P r o p e r t i e s  49  Optical Properties  50  Comparison o f West C o a s t  Groundwood  and C a u s t i c T r e a t e d Gmelina P u l p s Chemical  P u l p from Gmelina  The P o t e n t i a l o f G m e l i n a Pulps f o r Newsprint  V  33  C h i p p i n g and C h i p H a n d l i n g  1. 2.  IV  .  SUMMARY  ....  51 52  Mechanical 53  55  V  Chapter VI  Page CONCLUSIONS AND RECOMMENDATIONS  57  Conclusions  57  Recommendations  57  BIBLIOGRAPHY  59  TABLES  67  FIGURES  80  APPENDIX  97  L I S T OF  TABLES  Table 1.  Page Import of paper  and p a p e r b o a r d ,  Federal  Republic of Nigeria  67  2.  F i b e r c h a r a c t e r i s t i c s of Gmelina Arborea  3.  E f f e c t of chip s p e c i f i c a t i o n s i n pulping processes E f f e c t o f c h e m i c a l p r e t r e a t m e n t on t h e c h a r a c t e r i s t i c s o f open d i s c h a r g e and p r e s s u r e r e f i n e r p u l p s made f r o m s o f t w o o d s .  4.  5.  6.  7.  8.  9.  Dependence o f p h y s i c a l p r o p e r t i e s o f p u l p on L- a n d S - f a c t o r s  R e s u l t s o f Bauer-McNett c l a s s i f i c a t i o n Gmelina mechanical p u l p s . . . .  of  .  70  the 72 the 73  mechanical 74  Values o f Gmelina mechanical p u l p s p r o p e r t i e s e x t r a p o l a t e d a t 90 m l C s f R e s u l t s o f e v a l u a t i o n of Gmelina (caustic t r e a t e d ) p u l p and West C o a s t s t o n e groundwood  11.  R e s u l t s o f e v a l u a t i o n West C o a s t and s e m i - b l e a c h e d k r a f t (SBK) p u l p s  13.  69  71  10.  12.  68  mechanical  R e s u l t s of e v a l u a t i o n of the p r o p e r t i e s of Gmelina mechanical p u l p s  L- a n d S - f a c t o r s o f t h e G m e l i n a pulps  ...  75  76  Gmelina 77  Results of evaluation of simulated newsprint handsheets  78  Wet s t r e n g t h t e s t r e s u l t s o f t h e s i m u l a t e d newsprint mixes  79  vi  L I S T OF  FIGURES  Figure 1.  2.  Page P a r t c r o s s - s e c t i o n stem o f Gmelina Roxb. (2.4X) Use o f r e s i d u e m a t e r i a l s B r i t i s h Columbia  arborea "".  for pulping i n  a n d Canada  81  3.  Diagramatic r e p r e s e n t a t i o n of a t y p i c a l chip  4.  Photomicrograph untreated mechanical pulp s a m p l e (A) (40X) . P h o t o m i c r o g r a p h steam p r e t r e a t e d p u l p s a m p l e (B) (40X)  5.  6.  7.  Photomicrograph c a u s t i c pretreated pulp s a m p l e (C) (40X) . Photomicrograph p u l p sample  sodium  (D)  . . 80  sulfite  . . 82  83 84  .85  pretreated  (40X)  86  8.  Cellulose oxidation  87  9.  P h o t o m i c r o g r a p h West C o a s t s e m i - b l e a c h e d k r a f t p u l p (26X) Photomicrograph Gmelina semi-bleached k r a f t p u l p (26X)  88 88  P h o t o m i c r o g r a p h c r o s s - s e c t i o n West C o a s t s e m i - b l e a c h e d k r a f t p u l p f i b e r s (160X p h a s e contrast)  89  Photomicrograph c r o s s - s e c t i o n Gmelina semib l e a c h e d k r a f t p u l p f i b e r s (160X p h a s e contrast)  89  10.  11.  12.  vii  viii Figure 13.  14.  15.  16.  17.  18.  19.  20.  21.  22.  23.  Page G r a p h o f d e n s i t y on s e m i - b l e a c h e d k r a f t content of s i m u l a t e d newsprint handsheets  . .  90  G r a p h o f t e a r i n d e x on s e m i - b l e a c h e d k r a f t content of s i m u l a t e d newsprint handsheets  . .  90  G r a p h o f b u r s t i n d e x on s e m i - b l e a c h e d k r a f t content o f s i m u l a t e d newsprint handsheets . .  91  G r a p h o f b r e a k i n g l e n g t h on s e m i - b l e a c h e d k r a f t content of s i m u l a t e d newsprint handsheets . .  91  G r a p h o f s t r e t c h on s e m i - b l e a c h e d k r a f t content o f s i m u l a t e d newsprint handsheets  . .  92  G r a p h o f b r i g h t n e s s on s e m i - b l e a c h e d k r a f t content of s i m u l a t e d newsprint handsheets  . .  93  G r a p h o f o p a c i t y on s e m i - b l e a c h e d k r a f t content o f s i m u l a t e d newsprint handsheets  . .  93  Graph o f s c a t t e r i n g c o e f f i c i e n t on s e m i bleached k r a f t content of simulated newsprint handsheets  94  G r a p h o f a b s o r p t i o n c o e f f i c i e n t on s e m i bleached k r a f t content of simulated newsprint handsheets  94  G r a p h o f wet s t r e n g t h c h a r a c t e r i s t i c s (stress) on s e m i - b l e a c h e d k r a f t c o n t e n t o f s i m u l a t e d newsprint handsheets  95  G r a p h o f wet s t r e n g t h c h a r a c t e r i s t i c s (strain) on s e m i - b l e a c h e d k r a f t c o n t e n t o f s i m u l a t e d newsprint handsheets  96  ACKNOWLEDGEMENTS I w i s h t o e x p r e s s my s i n c e r e g r a t i t u d e  t othe  f o l l o w i n g i n d i v i d u a l s and g r o u p o f p e o p l e : L.  Roche, Dept. o f F o r .  J.S.  a n d Wood S c i e n c e ,  UCNW, B a n g o r ;  R e d h e a d , FAO; J . B . H a l l , D e p t . o f F o r .  Ibadan and Drs. Forestry,  Res. Mgt., U l ,  R.W. W e l l w o o d and D. H a l e y , F a c u l t y o f  UBC; C. K o w a l s k y , C h a r n e l l a n d A s s o c i a t e s  Ltd.,  V a n c o u v e r and E.R. S i e d l a k , SNC R u s t L t d . , M o n t r e a l , f o r m a t e r i a l s procurement: during materials  J . B a g l e y , WFPL, f o r h i s  preparation:  S. B e r g h o l d , P u l p i n g  B C I T , f o r g r a n t i n g me p e r m i s s i o n chipper:  L. V a l g , F a c u l t y  connection project:  with  and  to use t h e i r  Section,  experimental  o f F o r e s t r y , UBC, f o r a r r a n g i n g  t h e e n t i r e management a n d s t a f f o f MBR L t d . , s u p p o r t and f r i e n d s h i p : J.W.  Wilson,  l i t e r a t u r e h e s u p p l i e d me: L. P a s z n e r ,  o f F o r e s t r y , UBC, f o r d i r e c t i n g t h e w r i t e - u p , pertinent literature, materials assistance:  commitments.  b u t who, o t h e r w i s e ,  Finally,  Pulping  through  innumerable  t o t h o s e who I d i d n o t m e n t i o n  d e s e r v e t o b e r e m e m b e r e d , I a l s o s e n d my  gratitude. ix  with  supervisor, f o r  b a b y s i t t i n g my t h e s i s p r o j e c t , f r o m i t s e x p e r i m e n t a l , despite his  me  invaluable  i n d e f a t i g a b l e M. J a c k s o n , H e a d , M e c h a n i c a l  the d r a f t i n g s t a g e s t o c o m p l e t i o n ,  Faculty  supplying  a n d g i v i n g me o t h e r  S e c t i o n , MBR L t d . , V a n c o u v e r , a n d my r e s e a r c h  sincere  Vancouver,  o f F o r e s t r y , UBC, f o r t h e i n t e r e s t he showed i n my w o r k  the relevant  official  my  MBR L t d . w h e r e I c a r r i e d o u t ray r e s e a r c h  for t h e i r cooperation, Faculty  assistance  CHAPTER I INTRODUCTION Hardwood p u l p s h a v e g e n e r a l l y , i n t h e p a s t , b e e n u s e d i n t h e m a n u f a c t u r e o f t i s s u e and filler  pulps.  f i n e papers,  I n r e c e n t t i m e s , however, the  or  as  decreasing  a v a i l a b i l i t y of the p r e f e r r e d softwood s p e c i e s , the i n c r e a s ing  concern  and  t h e f o r e i g n e x c h a n g e c o n s e r v a t i o n p o l i c i e s o f some p u l p -  producing  r e g a r d i n g the w o r l d  f u t u r e demand f o r  c o u n t r i e s n o t endowed w i t h t h e f a v o r e d  fibers,  softwood  s p e c i e s , h a v e l e d t o an e v e r - i n c r e a s i n g i n c e n t i v e t o make use  o f hardwood p u l p s  i n d u s t r y c a n no wood p u l p s  f o r paper products.  p u l p and  longer a f f o r d the luxury of regarding  r e p o r t e d by A l a d e  and p a p e r b o a r d i n N i g e r i a was short tons)  i n 1975  (2 20,000 t o n s )  and  items,  1964  1965  (3), the consumption of a b o u t 111,583,723 k g  i s expected  by t h e y e a r  on t h e s e  19 80.  r e p o r t e d by FAO  i s shown i n T a b l e  e s s e n t i a l to p o i n t out  to reach  The  government's  Although  more  r i s e n remarkably  1963, recent  of  i t is  d u r i n g the  T h i s t r e n d c o n t i n u e s , , l a r g e l y as a r e s u l t o f  recently introduced u n i v e r s a l free primary and  education  t h e g e n e r a l a d v a n c e m e n t i n l i t e r a c y and  living. 1  kg  spending  (8), f o r the years I.  paper  199,580,643  t h a t the consumption of paper  p a p e r b o a r d i n N i g e r i a has  country,  hard-  (123,000  s u p p o r t i n g f i g u r e s are not a v a i l a b l e t o the w r i t e r ,  decade.  paper  j u s t as s e c o n d a r y m a t e r i a l . .  As  and  The  and past the i n the standard  2. Work by v a r i o u s r e s e a r c h e r s (4, 17, 18, 20, 26, 30, 27,  38, 5 1 , 58, 5 9 , 63, 65, 66, 68, 69, 70, 72, 74, 78) h a s  i d e n t i f i e d t h e p o t e n t i a l o f hardwood p u l p s f o r use i n f i b e r products.  Consequently,  a t t h e p r e s e n t t i m e , hardwood  pulps  a r e b e i n g u s e d more a n d more t o s u p p l e m e n t t h e s o f t w o o d material resource.  Even i n N o r t h America,  o f hardwoods a r e b e i n g c o n t e m p l a t e d manufacture  small  raw  percentages  f o r use i n n e w s p r i n t  (46).  The p r e s e n t s t u d y was c a r r i e d o u t w i t h t h e l i m i t e d o b j e c t i v e o f i n v e s t i g a t i n g the p r o p e r t i e s o f Gmelina  arborea  Roxb., a h a r d w o o d s p e c i e s grown e x t e n s i v e l y i n N i g e r i a ,  and  c o n s i d e r i n g f u t u r e p o t e n t i a l o f t h i s m a t e r i a l f o r use i n t h e manufacture  of newsprint.  S i n c e t h e m a i n component o f news-  p r i n t i s some f o r m o f m e c h a n i c a l p u l p , t h e m a j o r p a r t o f t h e s t u d y was c o n c e r n e d  w i t h assessing the p o t e n t i a l of  f o r t h i s type of pulp.  Gmelina  L a b o r a t o r y work has been c a r r i e d o u t  to determine  t h e p r o p e r t i e s o f open d i s c h a r g e r e f i n e r  from Gmelina  a n d t h e s e h a v e b e e n c o m p a r e d t o t h o s e o f mech-  a n i c a l p u l p s used America.  f o r the manufacture  pulp  of newsprint i n North  I n view o f the poor mechanical p r o p e r t i e s o f t h i s  type o f p u l p , t h r e e p o s s i b l e approaches s t r e n g t h p r o p e r t i e s have b e e n e v a l u a t e d . presteaming  t o upgrading the These have i n c l u d e d  of the chips p r i o r to r e f i n i n g without  t r e a t m e n t as w e l l as p r e s t e a m i n g  chemical  w i t h two d i f f e r e n t t y p e s o f  chemical p r e t r e a t m e n t s . I n o r d e r t o complete  the p i c t u r e ,  a  3. b r i e f e v a l u a t i o n was o f the  a l s o c a r r i e d out  s p e c i e s a s a raw  to assess  material for kraft  pulp.  the p o t e n t i a l  CHAPTER I I LITERATURE SURVEY General  Introduction G m e l i n a , a member o f t h e A n g i o s p e r m o u s  family,  Verbenaceae, i s indigenous t o T r o p i c a l A s i a and A u s t r a l i a (48).  I t i s known b y t h e f o l l o w i n g v e r n a c u l a r  names -  Gumhar, Sewan, G o m a r i , S h i v a n , S h i v a n i , Gumadi,  Yemani,  and i n e x o t i c p l a n t a t i o n s a s Yemane o r G m e l i n a ( 5 7 ) . G m e l i n a has been i n t r o d u c e d and S o u t h A m e r i c a  t o A f r i c a and C e n t r a l  (6) a n d , i n t h e s e p l a c e s ,  a wide range o f u s e s : i n c o n s t r u c t i o n work,  has been p u t t o general  carpentry,  p a c k a g i n g and i n t h e cheaper grades o f f u r n i t u r e .  I t peels  w e l l a n d h a s b e e n f o u n d t o be s u i t a b l e f o r u s e as c o r e i n plywood manufacture  (6, 1 6 ) , f o r match boxes and s p l i n t s  (6), and f o r c o n s t r u c t i o n plywood (26) c o n s i d e r e d  (16). Chittenden  eta l .  G m e l i n a t o be an e x t r e m e l y p r o m i s i n g  for pulp production  stock  i n N i g e r i a and o t h e r  where s u i t a b l e g r o w i n g c o n d i t i o n s  tropical  f o r the species  S i l v i c u l t u r e , P l a n t a t i o n Establishment  species  countries exist.  and Growth  The s i l v i c u l t u r e o f G m e l i n a h a s b e e n d i s c u s s e d number o f d i f f e r e n t p u b l i c a t i o n s  (10, 12, 5 7 ) .  in a  Gmelina i s  e a s i l y e s t a b l i s h e d i n p l a n t a t i o n s because o f i t s a d a p t a b i l i t y t o a wide range o f s o i l and c l i m a t i c c o n d i t i o n s .  I t fruits  r e g u l a r l y and p l e n t i f u l l y and t h e seeds have a h i g h  4  germinative  5. power, which  h a s b e e n shown b y Lamb  length of storage period. ations i s relatively  (5 7) t o d e c r e a s e  with the  The c o s t o f e s t a b l i s h m e n t i n p l a n t -  l o w a n d , a s e s t i m a t e d b y FAO ( 8 ) ,  amounted t o $82 t o $99 US d o l l a r s p e r a c r e i n N i g e r i a , i n 1968. The  r a t e o f growth i s i n i t i a l l y  after the f i r s t  7 years  f a s t , b u t decreases  (57, 6 9 ) . Palmer  t h a t , g i v e n good growing  (69) e s t i m a t e d  c o n d i t i o n s and a r o t a t i o n o f 7 t o 8  y e a r s , t h e p l a n t a t i o n a r e a r e q u i r e d t o s u s t a i n a 300 t / d a y (100,000 t / a ) k r a f t p u l p m i l l w o u l d be 15,000 h a . Although plicity  a species r a t e o f growth i s a f u n c t i o n o f a m u l t i o f f a c t o r s , Gmelina i s g e n e r a l l y able t o produce  p u l p w o o d i n 6 t o 10 y e a r s  (8, 6 9 ) . A c c o r d i n g t o Obiaga and  Wayman ( 6 5 ) , u n d e r f a v o u r a b l e c o n d i t i o n s , G m e l i n a c o u l d produce a crop o f timber s i z e s u i t a b l e 4 years a f t e r p l a n t i n g .  f o r pulpwood i n 3 t o  They b a s e d t h i s d e d u c t i o n o n t h e  Nigerian experience with the species. As in  Nigeria  r e p o r t e d by Palmer i s 84 m / h a 3  a f t e r 12 y e a r s g r o w t h , or  laterite  (69) , t h e g r o w t h o f G m e l i n a  (1,200 f t / a c ) o n p o o r s a n d y 3  210 m /ha  soils  (3,000 f t / a c ) o n g o o d  3  3  s o i l s a f t e r 12 y e a r s g r o w t h ,  a n d 252 m / h a 3  clay (3,600  f t / a c ) o n t h e m o s t f a v o r a b l e s a v a n n a s i t e s a f t e r 10 y e a r s 3  growth.  A maximum v a l u e o f 252 m /ha h a s b e e n r e c o r d e d f o r  t h e R a i n F o r e s t Zone a f t e r  3  8 .years g r o w t h .  Chittenden e ta l .  (2 6) p o i n t e d o u t t h a t t h e s e v a l u e s c o r r e s p o n d  t o a mean  annual  6. i n c r e m e n t o f 7 t o 31.5 m / h a / a , f o r h i g h f o r e s t a r e a s .  Yeom  3  and  Sandrasegaran  (92) s u m m a r i z e d t h e M a l a y a n e x p e r i e n c e  G m e l i n a b y i n d i c a t i n g t h a t t h e mean y i e l d a t a s p a c i n g o f 10 x 10 f t ( a p p r o x . o r d e r o f 259 m /ha 3  years. tions,  with  from a p l o t p l a n t e d  3 x 3 meters) i s o f t h e  (3,700 f t / a c ) b e t w e e n t h e a g e s o f 7 t o 9 3  These f i g u r e s , however, r e p r e s e n t  i d e a l growth  condi-  a n d i t h a s b e e n p o i n t e d o u t (12) t h a t u n l e s s c a r e f u l  a t t e n t i o n i s p a i d t o c l e a n c u l t i v a t i o n o f young s t a n d s , t h e g r o w t h a n d y i e l d o f t h e s p e c i e s a r e b o u n d t o be p o o r . The  p r i n c i p a l enemies o f Gmelina i n c l u d e p a r a s i t e s ,  insect pests, fungal diseases damage.  and f r o s t ,  U n d e r a n y one o r more o f t h e s e  growth and y i e l d o f t h e s p e c i e s w i l l Gmelina coppices  fire  and h u r r i c a n e  conditions, both the  suffer.  w e l l and i t s growth a f t e r t h e f i r s t  c l e a r - f e l l i n g and subsequent second, t h i r d and even f o u r t h r o t a t i o n o n t h e o r i g i n a l stump h a s shown no r e d u c t i o n i n yield.  A s i n d i c a t e d b y FAO  ( 8 ) , a G m e l i n a p l a n t a t i o n may  r e q u i r e r e p l a n t i n g o n l y once e v e r y  50 y e a r s .  Wood a n d F i b e r P r o p e r t i e s G m e l i n a wood i s y e l l o w i s h - g r a y o r p i n k i s h - w h i t e , changing t o brownish-yellow Figure  1, i t / i s  f a s t growth r a t e .  h a s a d e n s i t y o f 497 kg/m  content,  A s shown c l e a r l y i n  d i f f u s e - p o r e d , f i r m and o f u n i f o r m  despite the species it  w i t h age.  a n d 625 kg/m  3  3  As r e p o r t e d  (31 l b / f t ) 3  (39 l b / f t ) 3  density ( 7 , 93)  a t 12% m o i s t u r e  a t 50% m o i s t u r e  content.  7. Palmer to  (69) r e p o r t e d a d e n s i t y r a n g e o f 380 t o 420 kg/m  26 l b / f t ) . 3  (24  3  A s p o i n t e d o u t by Lamb ( 5 7 ) , a n d o t h e r s ( 6 ) ,  t h e d e n s i t y o f G m e l i n a wood i s c o m p a r a b l e t o t h a t o f B a l t i c redwood  (Pinus The  istics (2,  silvestris).  gross  wood a n d f i b e r m o r p h o l o g i c a l  o f G m e l i n a have been d i s c u s s e d by v a r i o u s  researchers  7, 10, 30, 4 4 , 6 7 , 6 9 , 70, 8 4 ) . I n T a b l e I I , d a t a o n  Gmelina f i b e r • c h a r a c t e r i s t i c s a r e given. (26), are  character-  Chittenden  et a l .  p o i n t e d o u t t h a t t h e f i b e r c h a r a c t e r i s t i c s o f Gmelina comparable t o those  aspen  o f o t h e r hardwoods, p a r t i c u l a r l y  (Populus.tremuloides),  b i r c h (Betula alba)  with  and v a r i o u s  species o f Eucalyptus. As  i s common w i t h h a r d w o o d s , G m e l i n a h a s o n l y one  k i n d o f f i b e r i n t h e growth zone.  Softwoods g e n e r a l l y c o n t a i n  two  (EW) t r a c h e i d s , w i t h  types  - the f l e x i b l e earlywood  c e l l w a l l s , and t h e s t i f f e r thicker fiber walls.  latewood  thin  (LW) t r a c h e i d s , w i t h  The r e l a t i v e amounts o f t h e s e  two t y p e s  o f f i b e r components s t r o n g l y a f f e c t t h e y i e l d and q u a l i t y o f pulps.  T h u s a h i g h e r p r o p o r t i o n o f LW t r a c h e i d s r e l a t i v e t o  t h e EW t r a c h e i d s p o r t i o n r e s u l t s i n a h i g h e r y i e l d o f p u l p p e r u n i t v o l u m e o f wood.  F u r t h e r m o r e , t h e p r o p o r t i o n s o f LW a n d  EW a f f e c t p u l p q u a l i t y t h r o u g h t h e d i f f e r e n c e i n t h e i r wall thickness.  cell-  A h i g h p r o p o r t i o n o f EW t r a c h e i d s r e s u l t s i n  a b e t t e r f i b e r c o n f o r m a b i l i t y during sheet formation. conformability results i n larger fiber to fiber contact  Fiber areas,  8. thus enhancing i n t e r f i b e r . b o n d i n g .  C o n s e q u e n t l y , i t has  p o s i t i v e e f f e c t on t h e c h a r a c t e r i s t i c s o f a p u l p . o t h e r h a n d , p u l p s w i t h h i g h e r LW  the  t r a c h e i d proportions are  u s u a l l y h a r d a n d y i e l d b u l k y p a p e r s b e c a u s e LW conform r e a d i l y .  On  f i b e r s do  fiber  of  conformability  and t h u s a l s o l e a d t o t h e f o r m a t i o n o f s h e e t s o f good  density.  Studies  A l i m i t e d number o f p u l p i n g s t u d i e s h a v e b e e n out  not  Nevertheless, the f i b e r c h a r a c t e r i s t i c s  G m e l i n a , as g i v e n i n T a b l e I I , e n h a n c e  Previous Pulping  a  carried  o n G m e l i n a and a l m o s t a l l h a v e b e e n c o n c e r n e d w i t h  the  p o t e n t i a l o f t h e s p e c i e s f o r use i n t h e m a n u f a c t u r e o f chemical  or semichemical pulps.  A d e t a i l e d review of these  s t u d i e s w i l l , t h e r e f o r e , n o t be a t t e m p t e d , b u t r a t h e r main  f i n d i n g s w i l l be In  their  summarized.  1 9 6 1 , Guha and S a x e n a  p u l p i n g s t u d i e s of Gmelina.  (37) c a r r i e d o u t  T h e i r s t u d i e s showed  sulfate Gmelina  s u l f a t e p u l p t o be s u i t a b l e f o r t h e m a n u f a c t u r e o f w r i t i n g and w r a p p i n g p a p e r s .  They a l s o c a r r i e d o u t a c h e m i c a l  a n a l y s i s o f G m e l i n a wood and showed i t t o h a v e a h i g h  cellu-  l o s e c o n t e n t , comparing f a v o r a b l y w i t h o t h e r m a t e r i a l s ally  used f o r papermaking. C h i t t e n d e n e t a l . (26) r e p o r t e d t h e r e s u l t s  s u l f a t e and n e u t r a l s u l f i t e of  gener-  of  s e m i c h e m i c a l (NSSC) p u l p i n g  trials  G m e l i n a a n d showed t h a t t h e u n b l e a c h e d s u l f a t e p u l p c o u l d  be u s e d i n t h e p r o d u c t i o n o f l o w e r g r a d e s o f w r a p p i n g p a p e r s .  9. They a l s o showed t h e b l e a c h e d p r o d u c t s t o be s u i t a b l e f o r a w i d e r a n g e o f w r i t i n g a n d p r i n t i n g p a p e r s , w h i l e t h e NSSC p u l p w o u l d be s u i t a b l e , i n t h e u n b l e a c h e d c o n d i t i o n , f o r t h e manufacture o f p a p e r b o a r d f o r c a r t o n s and b o a r d They c o n s i d e r e d t h a t a r a t h e r h i g h e r q u a l i t y  manufacture.  semichemical  pulp should f i n d a p p l i c a t i o n f o r the manufacture  of lower  a n d i n t e r m e d i a t e g r a d e s o f book a n d m a g a z i n e p a p e r s . Peh  (72) o b t a i n e d g o o d y i e l d s o f u n b l e a c h e d a n d  bleached s u l f a t e pulps o f Gmelina.  H i s s t u d y showed  that  t h e p h y s i c a l s t r e n g t h p r o p e r t i e s o f b l e a c h e d and unbleached s u l f a t e p u l p s from Gmelina were b e t t e r t h a n t h o s e o f t h e A u s t r a l i a n commercial E u c a l y p t s u l f a t e pulp.  He  carried  o u t h i s s t u d y o n G m e l i n a grown i n M a l a y a . O b i a g a a n d Wayman ( 6 5 ) , s t u d i e d t h e k i n e t i c s o f d e l i g n i f i c a t i o n of Gmelina sulfide pulping.  from N i g e r i a i n k r a f t and p o l y -  They d e m o n s t r a t e d t h a t o v e r a Kappa number  r a n g e o f 25 t o 34, p o l y s u l f i d e d i g e s t i o n s o f G m e l i n a i n p u l p y i e l d s o f 55 t o 64%.  resulted  They f o u n d t h e s e v a l u e s t o be  a b o u t 1 0 % . h i g h e r t h a n t h e y i e l d s o f k r a f t p u l p s i n t h e same Kappa number r a n g e . B a l l o n e t a l . (17) i n d i c a t e d t h a t u n b l e a c h e d  yields  o f t h e o r d e r o f 57 t o 5 8% c o u l d be a c h i e v e d f r o m G m e l i n a by the s u l f a t e p u l p i n g p r o c e s s .  Their results d i f f e r  markedly  from t h o s e r e p o r t e d i n most l i t e r a t u r e and t h a t o b t a i n e d i n the p r e s e n t s t u d y , about 50%, b u t i s s i m i l a r t o t h a t by P a l m e r  (69), f o r P h i l i p p i n e t r i a l s  reported  digested f o r a short  10. t i m e a t maximum t e m p e r a t u r e . d e t a i l s o f the cooking c h i p s were n o t f u l l y  B a l l o n e t a l . d i d not mention  c o n d i t i o n , b u t i t does appear t h a t t h e  cooked.  I f , indeed,  undercooked, then the low b l e a c h i n g  chemical  r e p o r t e d a p p e a r s t o be i n c o n s i s t e n t . w o r k showed t h a t t h e b l e a c h e d  t h e c h i p s were requirement  Nevertheless,  they  their  k r a f t p u l p o f G m e l i n a may  serve  i n t h e p r o d u c t i o n o f g o o d q u a l i t y b o n d and w r i t i n g p a p e r s . They c i t e d a n u n p u b l i s h e d on P h i l i p p i n e - g r o w n  work by E s t u d i l l o and a s s o c i a t e s ,  m a t e r i a l , w h i c h showed t h a t i n t h e s u l -  f a t e p u l p i n g of Gmelina, pulp y i e l d 60.4%  increased  f r o m 52.7 t o  w i t h a n i n c r e a s e i n s u l f i d i t y up t o 4 5 % .  This  seems  c o n s i s t e n t w i t h t h e work o f O b i a g a a n d Wayman ( 6 5 ) , a l t h o u g h the c o n d i t i o n s o f t h e cook were n o t i n d i c a t e d . a l s o showed a p p r o x i m a t e l y  The  pulps  t h e same d e g r e e o f b l e a c h a b i l i t y  w i t h a l m o s t i d e n t i c a l p e r m a n g a n a t e numbers a t 11 ± 0.5. E s t u d i l l o e t a l . (30) s t u d i e d t h e e f f e c t s o f s u l f i d i t y and l e n g t h o f c o o k i n g bility  t i m e on p u l p y i e l d ,  bleacha-  and m e c h a n i c a l p r o p e r t i e s o f G m e l i n a grown i n t h e  Phillipines.  They e s t a b l i s h e d t h e o p t i m u m p u l p i n g  t o be a t 25.5% s u l f i d i t y  and an a c t i v e a l k a l i o f 15.6%, u s i n g  a l i q u o r t o wood r a t i o o f 4:1 and a 30 t o 90 m i n u t e schedule  a t a maximum t e m p e r a t u r e o f 338°F Palmer  obtained  conditions  cooking  (170°C).  (69) r e p o r t e d p u l p i n g t r i a l s o f G m e l i n a  from seven d i f f e r e n t c o u n t r i e s .  the major f i n d i n g s d e s c r i b e d  The f o l l o w i n g w e r e  i n h i s report:  1.  P u l p i n g t r i a l s by t h e s u l f a t e p r o c e s s  t i o n w i t h about 15% a c t i v e a l k a l i in  showed t h a t  a t 338°F (170°C) r e s u l t e d  an u n b l e a c h e d p u l p o f 50% y i e l d .  The p u l p h a d g o o d  s t r e n g t h c h a r a c t e r i s t i c s a n d c o u l d be b l e a c h e d degree o f b r i g h t n e s s adopting sequences: be  four different  CEHH, HEH, CEH a n d CEHD.  to a high bleaching  The p u l p was f o u n d t o  comparable o r s u p e r i o r t o hardwood p u l p s  of Eucalyptus,  diges-  such as those  b i r c h a n d p o p l a r , a n d t o be u s e f u l f o r w r i t i n g ,  p r i n t i n g , bond, o n i o n s k i n and w r a p p i n g p a p e r s . 2.  In t r i a l s  by t h e NSSC p r o c e s s ,  u n b l e a c h e d p u l p was o b t a i n e d t h i s type o f pulp.  b e t w e e n 66 a n d 76% o f  with satisfactory  The p u l p c o u l d b e f u l l y  strengths f o r  bleached  o n l y by  u s i n g a h i g h a p p l i c a t i o n o f c h l o r i n e , and t h e s t r e n g t h and brightness characteristics of the f u l l y were comparable t o t h o s e lower  (600  I n g e n e r a l , over a wide range o f drainage t o 200 C a n a d i a n s t a n d a r d  freeness  With  f o l d i n g strengths)  characteristics  (Csf)), a l l properties  on t h e b o n d i n g o f f i b e r s  (tensile,  constant.  The M a l a y a n t r i a l  showed a m a r k e d i n c r e a s e i n t e a r i n g s t r e n g t h  increased beating.  This  unrealistic.  differed  with  increase i n tearing strength  i n c r e a s e d b e a t i n g r e p o r t e d f o r t h e Malayan t r i a l , appears  bursting  increase with beating, but the tearing  s t r e n g t h remains f a i r l y and  s u l f a t e pulp.  pulp  obtained.  t h a t depend m a i n l y and  NSSC  a p p l i c a t i o n l e v e l s of c h l o r i n e , a u s e f u l semi-bleached  p u l p was 3.  of bleached  bleached  with  however,  12. 4.  In sulfite  d i g e s t i o n s , r a t h e r s e v e r e c o n d i t i o n s were  r e q u i r e d f o r p u l p i n g a n d t h e p u l p was i n f e r i o r t o s u l f a t e p u l p s i n s t r e n g t h c h a r a c t e r i s t i c s and, i n t h e case o f bleached pulp, i n brightness. 5.  C o l d soda s e m i c h e m i c a l p u l p s were o b t a i n e d i n y i e l d s o f  a b o u t 80%.  The p u l p s w e r e b u l k i e r a n d w e a k e r t h a n  p u l p s a n d a l s o more d i f f i c u l t  t o bleach t o a lower  sulfate bright-  ness . Palmer and Gibbs  ( 7 0 ) , i n 1974, f o u n d t h a t  Gmelina  s u l f a t e p u l p s c o u l d be b l e a c h e d t o a good b r i g h t n e s s  follow-  i n g a s i m p l e f o u r - s t a g e b l e a c h i n g sequence and d e m o n s t r a t e d t h a t t h e b l e a c h e d s u l f a t e p u l p gave d e n s e r s h e e t s t h a n t h o s e o f hardwoods from S o u t h e r n U n i t e d S t a t e s o f A m e r i c a and E u c a l y p t s from A u s t r a l i a .  They a l s o showed t h e y i e l d o f  G m e l i n a s u l f a t e p u l p s t o be c o m p a r a b l e t o t h o s e o f h a r d w o o d s from t h e Southern U n i t e d S t a t e s o f America, p u l p e d under similar  conditions. A r e c e n t FAO s t u d y  (10) showed t h a t i n t h e s u l f a t e  p u l p i n g o f Gmelina, the consumption o f a c t i v e a l k a l i  depended  t o some e x t e n t o n s p e c i e s p r o v e n a n c e s , w h e r e a s NSSC p u l p i n g was n o t a f f e c t e d by s p e c i e s p r o v e n a n c e o r p l a c e o f o r i g i n . Sosanwo (8 3) c a r r i e d o u t k r a f t a n d s u l f a t e - o x y g e n (two-stage) d i g e s t i o n s o f Gmelina c h i p s .  He f o u n d  that  u n b l e a c h e d Gmelina k r a f t p u l p compared f a v o r a b l y i n p h y s i c a l p r o p e r t i e s t o unbleached b i r c h k r a f t p u l p and t h a t t h e  b l e a c h i n g o f t h e s u l f a t e p u l p was  not a s s o c i a t e d w i t h a  o f p u l p p h y s i c a l s t r e n g t h , t h u s c o n f i r m i n g an e a r l i e r v a t i o n by C h i t t e n d e n e t a l . ( 2 6 ) . k r a f t and  s i n g l e mechanical  r e p o r t e d i n t h e l i t e r a t u r e was I n t h i s s t u d y i t was  a l s o showed G m e l i n a  p u l p i n g s t u d y on  reduced  Orgill  shown t h a t i m p r e g n a t i n g  (Na2S03) p r i o r t o t h e r m o m e c h a n i c a l power consumption,  Gmelina  t h a t c a r r i e d o u t by  c h i p s w i t h a m i x t u r e of sodium hydroxide sulfite  lowered  t h a t Gmelina thermomechanical  Gmelina  (NaOH) a n d  sodium  pulping  (TMP)  s h i v e c o n t e n t and  the s t r e n g t h p r o p e r t i e s of the pulp.  The  improved  study a l s o  p u l p w o u l d f i n d use  the main requirement  of the pulp i s i t s a b i l i t y  l i q u i d under p r e s s u r e . o f t h e s p e c i e s f o r use Mechanical  absorb potential  manufacture.  Pulping  The  term, mechanical  r e f e r s to those pulps produced wood by m e c h a n i c a l  means.  p u l p , i s a g e n e r i c one  pulps a l l f a l l  Thus c o n v e n t i o n a l s t o n e  i n t h i s category.  a r e c h a r a c t e r i z e d by e x t r e m e l y  and  by t h e d i r e c t a t t r i t i o n  p u l p , c h e m i g r o u n d w o o d p u l p and  on wood)  to  where  O r g i l l d i d not c o n s i d e r the i n newsprint  suggested  i n the  m a n u f a c t u r e o f d i a p e r s and o t h e r d i s p o s a b l e p r o d u c t s  (SGW)  obser-  s u l f a t e - o x y g e n p u l p s t o have comparable p r o p e r t i e s . The  (68).  He  loss  chip refiner  Mechanical  high y i e l d  groundwood mechanical  pulping  (above 9 0%,  (89), s i n c e the l i g n i n b i n d e r , which  of  processes based  i s removed i n  t h e c a s e o f c h e m i c a l p u l p i n g , r e m a i n s a s an i n t e g r a l p a r t o f  14. the f i b e r i n mechanical p u l p s .  M e c h a n i c a l p u l p i s the main  component o f t h e n e w s p r i n t f u r n i s h and n e w s p r i n t was  produced  c h e m i c a l p u l p and advent  until  fairly  f r o m a m i x t u r e o f 2 0 t o 30  percent  80 t o 70 p e r c e n t m e c h a n i c a l p u l p .  of higher strength mechanical  i n t h e l a s t few y e a r s has  o f f e r e d some p o t e n t i a l  c a s e s , i t has b e e n p o s s i b l e t o e l i m i n a t e ,  c h e m i c a l p u l p component f r o m n e w s p r i n t The  The  or pseudomechanical  i n one  furnish.  essentially,  t h e d i r e c t a t t r i t i o n o f wood i n a g r i n d i n g p r o c e s s i n a r e f i n i n g process t i o n of r e l a t i v e l y  (RMP  o r TMP),  of  involve (SGW), o r  w i t h or without the a d d i -  s m a l l amounts o f c h e m i c a l s .  These v a r i o u s  processes f o r the p r o d u c t i o n of mechanical p u l p are  1.  or  completely, the  b a s i c p r i n c i p l e s i n v o l v e d i n the manufacture  t h e s e m e c h a n i c a l p u l p s a r e s i m p l e and,  outlined  pulps  for reducing  t h e c h e m i c a l p u l p c o n t e n t o f n e w s p r i n t f u r n i s h and two  recently,  briefly  below.  Stone  Groundwood The  SGW  (SGW)  Process  process i n v o l v e s the a t t r i t i o n  of logs of  wood by p r e s s i n g them a g a i n s t t h e a b r a s i v e s u r f a c e o f a r o t a t i n g g r i n d s t o n e i n the presence t h e wood i s r e d u c e d  to pulp.  The  of water.  water  By t h i s  c o o l s and  means,  lubricates  t h e g r i n d i n g s u r f a c e and a l s o conveys t h e p u l p i n t o t h e p i t . The  SGW  p r o c e s s i s one  is difficult  o f random a t t r i t i o n a n d ,  t o b r i n g under t e c h n i c a l c o n t r o l .  groundwood p u l p s a r e s u b j e c t t o a wide range  as a  result,  Consequently,  of v a r i a t i o n i n  15. p h y s i c a l p r o p e r t i e s , one o f the main c o n t r i b u t i n g being the g r a d u a l wearing  and consequent  the stone s u r f a c e c h a r a c t e r i s t i c s .  factors  change i n shape of  Furthermore,  a large  number o f g r i n d e r s are r e q u i r e d t o supply the mechanical requirements  of modern newsprint machines.  pulp  Thus the proper-  t i e s of the pulp f e d to the machine depend on the p r o p e r t i e s o f the pulp produced The SGW  a t each i n d i v i d u a l g r i n d s t o n e .  process causes e x t e n s i v e f i b e r damage and,  as a consequence, the r e s u l t i n g p u l p s have r e l a t i v e l y strengths.  poor  N e v e r t h e l e s s , i t s h i g h y i e l d o f pulp o f good bulk,  high o p a c i t y and good p r i n t i n g p r o p e r t i e s , makes i t h i g h l y d e s i r a b l e f o r newsprint. The chemigroundwood process e s s e n t i a l l y i n v o l v e s a treatment of the wood raw m a t e r i a l , i n g r i n d e r l e n g t h s , w i t h chemicals p r i o r to g r i n d i n g .  To ensure adequate l i q u o r pene-  tration., the chemical treatment i s u s u a l l y c a r r i e d out i n l a r g e cooking v e s s e l s a t e l e v a t e d temperature A complete  and p r e s s u r e .  l i q u o r p e n e t r a t i o n , however, does not seem to be  tenable w i t h m a t e r i a l i n g r i n d e r l e n g t h s , but i n g e n e r a l , the extent of p e n e t r a t i o n r e f l e c t s s p e c i e s anatomical d i f f e r e n c e s . N e v e r t h e l e s s , the process e n t a i l s a s i z e a b l e c a p i t a l  invest-  ment and t h i s i s probably one of the main reasons f o r i t s limited  acceptance.  16. 2.  Chip Refiner Mechanical a)  Pulping  Chip R e f i n e r Mechanical Pulp  (RMP)  Compared t o t h e SGW p r o c e s s ,  chip r e f i n e r  mechanical  p u l p i n g p r o m o t e s t h e p r e s e r v a t i o n o f f i b e r l e n g t h , one o f t h e two  factors considered  a strong pulp. and N e l s o n not  t o be e s s e n t i a l f o r t h e d e v e l o p m e n t o f  I t h a s , however, been p o i n t e d  (74), and J a c k s o n  o u t by  Peterson  ( 4 6 ) , t h a t t h e RMP p r o c e s s  does  do much t o e n h a n c e t h e b o n d i n g c h a r a c t e r i s t i c s o f a p u l p .  C o n s e q u e n t l y , t h o s e p h y s i c a l p r o p e r t i e s o f p a p e r w h i c h depend s o l e l y on t h e b o n d i n g p o t e n t i a l o f t h e f i b e r s a n d t h u s on t h e hydrodynamic s u r f a c e  area  of the pulp  mechanical pulping process,  are not l i k e l y  improved beyond t h e l e v e l o b t a i n e d  pulp  significantly  pulps.  on c h i p r e f i n e r  mechani-  i s beyond t h e scope o f t h i s t h e s i s , b u t has been  published b)  t o be  w i t h SGW  A more d e t a i l e d i n f o r m a t i o n cal  as i t emerges f r o m t h e  e l s e w h e r e by K e a y s a n d L e a s k ( 5 0 ) .  Thermomechanical Process  (TMP)  A l t h o u g h TMP h a s b e e n known f o r a l o n g t i m e , i t s a p p l i c a t i o n had been l i m i t e d t o t h e m a n u f a c t u r e o f b o a r d , f l o o r i n g and r o o f i n g f e l t s .  I t i s only during  the l a s t  five  y e a r s t h a t TMP h a s b e e n e m p l o y e d e x t e n s i v e l y i n t h e m a n u f a c ture of newsprint grades  ( 1 9 ) . The l a s t two I n t e r n a t i o n a l  Mechanical Pulping Conferences i m p o r t a n c e o f TMP t o t h e p u l p  (IMPC) (49) h i g h l i g h t e d t h e and paper i n d u s t r y .  TMP h a s  brought about a s i g n i f i c a n t improvement i n t h e p r o p e r t i e s o f  17. r e f i n e r mechanical pulps. A l t h o u g h , i n p r i n c i p l e , t h e TMP p r o c e s s i s s i m i l a r t o open d i s c h a r g e r e f i n i n g , tant aspects.  i td i f f e r s  f r o m i t i n two i m p o r -  In contrast to conventional chip refining, the  c h i p s f o r TMP a r e p r e h e a t e d i n h i g h t e m p e r a t u r e range  250 t o 260°F  of 2 t o 3 minutes.  (121 t o 130°C) Furthermore,  steam i n t h e  ( 1 9 , 46, 47) f o r a p e r i o d the f i r s t  r e f i n i n g stage of  the o p e r a t i o n i s a l s o c a r r i e d out a t e l e v a t e d pressure o f about  30 p s i g t h u s e n s u r i n g h i g h t e m p e r a t u r e  zone,  and t h e e l i m i n a t i o n o f problems  generation i n the r e f i n e r . two  i n the refining  a s s o c i a t e d w i t h steam  R e f i n i n g g e n e r a l l y proceeds i n  s t a g e s , t h e p r e s s u r e i n t h e p r i m a r y s t a g e b e i n g above  atmospheric i n order t o maintain the pulp temperature i n the range  240 t o 250°F  (115 t o 121°C).  The s e c o n d  stage o f  the p r o c e s s i s c a r r i e d out a t atmospheric p r e s s u r e as i n t h e c a s e o f RMP.  As r e p o r t e d ( 5 ) , t h r e e - s t a g e r e f i n i n g i s c a r r i e d  o u t u s i n g one o f t h e two C-E B a u e r TMP s y s t e m s and a l s o a t t h e B o w a t e r C a r o l i n a m i l l The  at Blandin,  i n Catawba.  TMP p r o c e s s p r e s e r v e s f i b e r l e n g t h a n d a l s o  enhances t h e development o f good b o n d i n g p o t e n t i a l .  Since  most o f t h e c o n v e n t i o n a l p h y s i c a l p r o p e r t i e s o f m e c h a n i c a l p u l p s c a n be a s c r i b e d t o t h o s e p a r a m e t e r s , p e r t i e s o f thermomechanical  the physical  pulps are generally better  t h o s e o f open d i s c h a r g e r e f i n e r p u l p s and s i g n i f i c a n t l y s u p e r i o r t o t h o s e e x h i b i t e d by s t o n e groundwood p u l p s .  prothan  18. c)  S i g n i f i c a n c e of Chip R e f i n e r Mechanical P u l p i n g Both  of  t h e RMP  and  TMP  processes permit the  good q u a l i t y p u l p from c h i p p e d  m a t e r i a l s and  f o r e s t and  manufacture  sawmill residue  thereby b r i n g about a c o n s i d e r a b l e e x t e n s i o n i n  forest resource u t i l i z a t i o n .  This i s p a r t i c u l a r l y  significant  i n a r e a s where t h e r e i s s e r i o u s c o m p e t i t i o n f o r pulpwood, i n the P a c i f i c Northwest and  coast of North America,  sawmill operations generate  erials.  The  use  where l o g g i n g  l a r g e v o l u m e s o f r e s i d u e mat-  o f r e s i d u e m a t e r i a l s f o r p u l p i n g has  p h e n o m e n a l i n r e c e n t t i m e s and  or  the t r e n d i s s t e a d i l y  become rising.  F i g u r e 2 shows t h e t r e n d i n t h e u s e o f r e s i d u e m a t e r i a l f o r pulping i n B r i t i s h  Columbia  and  Canada i n g e n e r a l  (24).  A p a r t f r o m t h e e x t e n s i o n o f t h e raw m a t e r i a l b a s e , r e f i n e r mechanical  p u l p i n g processes o f f e r the opportunity f o r  i n c o r p o r a t i n g a more e f f e c t i v e  chemical treatment  p o s s i b l e w i t h the chemigroundwood p r o c e s s . K e a y s and L e a s k hydroxide  As  than i s  d i s c u s s e d by  ( 5 0 ) , a number o f c h e m i c a l s , i n c l u d i n g  (NaOH), s o d i u m b i s u l f i t e  (NaHSOs) and  sodium  sodium sulfite  ( N « 2 S 0 ) h a v e b e e n u s e d on h a r d w o o d s w i t h b e n e f i c i a l  effects.  Sodium b o r o h y d r i d e  75),  3  i s extremely  (NaHB4) may  a l s o be  used  (36, 61,  but  expensive.  Refiner mechanical  p u l p s have g e n e r a l l y  s t r e n g t h p r o p e r t i e s o v e r s t o n e groundwood and mits a r e d u c t i o n i n the expensive paper products.  As q u o t e d  improved  t h e i r use  per-  c h e m i c a l p u l p component i n  by K e a y s and L e a s k  (50), s u c c e s s f u l  19. trials 100%  h a v e b e e n made on t h e p r o d u c t i o n o f n e w s p r i n t  open d i s c h a r g e  d u c e d was,  r e f i n e r groundwood.  h o w e v e r , b u l k y and  p o t e n t i a l and,  t h e r e f o r e , not  The  consequently  newsprint  used p r i n t i n g methods.  Keays  TMP  i n Sweden where i t was  i n the H a l l s t a m i l l  when TMP  replaced  t u r e o f 48.8 840  meters  g/m  2  75%  of the  c i t e d the p r o d u c t i o n  stone  found  that  groundwood i n the  manufac-  100%  TMP  r e d u c e d f r o m 22  been s p e c u l a t e d  A m e r i c a and  upon  Scandinavia  f o r short periods of time  (46).  c o s t s , but  (20,  t o 12%. 60)  have run  and 10 0%  chemical  The  use  several TMP  mechanical pulping processes  i n c l u d e , among o t h e r s ,  relatively  and  c o n t r o l r e s u l t s i n the p r o d u c t i o n  only  environmental pulp.  Other s i g n i f i c a n t c o n s i d e r a t i o n s i n favor of  labor content  mills  This s i n g l e f u r n i s h not  also decreases  of  newsprint  problems a s s o c i a t e d w i t h the manufacture of chemical  low  at  2  component c o u l d be  reduces production  of  (30 l b / 3 , 0 0 0 f t ) b a s i s w e i g h t n e w s p r i n t  pulp  i n North  to currently  (2,756 f t ) p e r m i n u t e m a c h i n e s p e e d , t h e  has  pro-  l a c k i n g i n bonding  i d e a l l y adaptable (49)  from  ease o f c o n t r o l .  refiner  their Better  of pulps with l e s s v a r i a -  t i o n , w h i c h , i n t u r n , r e l a t e s t o more s t a b l e p a p e r m a c h i n e operation.  F u r t h e r c o n s i d e r a t i o n of the  r e f i n e r mechanical pulping processes the present  s i g n i f i c a n c e of  i s beyond the  scope  the of  study.  Chipping For greater o p e r a t i o n a l e f f i c i e n c y  during  pulping,  20. it  i s e s s e n t i a l t o reduce pulpwood t o c h i p s , p r i o r t o f i b e r -  izing.  An o v e r a l l  tions i n pulp Figure  summary o f t h e e f f e c t o f c h i p  processing  3, a d i a g r a m a t i c  i s given  specifica-  i n Table I I I , while i n  representation of a t y p i c a l  chip i s  shown. Liquor penetration, and  water penetration,  related t o the t o t a l and  i n the case o f chemical  i n the case o f mechanical p u l p i n g , a r e  surface  area o f the s t a r t i n g  i s generally better the thinner the chip.  of debris o r r e j e c t materials the  pulping,  material,  The  increases with chip  s i t u a t i o n b e i n g more c r i t i c a l  incidence thickness,  i n t h e case o f hardwoods  than f o r softwoods, because o f p e n e t r a t i o n problems. length i s important  from t h e packing  during the charging  of the digester, while  cracks  uniform  size,  0.3 cm  fied,  ranging  and  and a l s o enhance  chippersproduce chips o f f a i r l y  f r o m 1.6 t o 1.9 cm  (0.1 i n ) t h i c k  according  corrugations  penetration.  Although conventional  and  density p o i n t o f view  relate to e f f e c t i v e chip thickness  l i q u o r and w a t e r  Chip  ( 6 1 ) , c h i p s may g e n e r a l l y be  t o s i z e , as o v e r - l a r g e ,  p i n c h i p s , and f i n e s i n a s c r e e n i n g chips are generally re-chipped through compression r o l l s  (0.6 t o 0.8 i n ) l o n g  over-thick,  operation.  classi-  accepts,  Over-large  and o v e r - t h i c k c h i p s  passed  t o c a u s e them t o c r a c k , w h i l e p i n  c h i p s and f i n e s a r e used as f u e l .  In present  times,  most m i l l s o b t a i n p a r t o r a l l o f t h e i r c h i p s u p p l y  however,  from  s i d e s o u r c e s and c h i p q u a l i t y i s n o t n e c e s s a r i l y under  outtheir  21. control. Chip Pretreatments The p r i m a r y o b j e c t i v e o f p r e t r e a t m e n t o f c h i p s p r i o r to r e f i n i n g or mechanical f i b e r i z i n g  i s t o achieve a  i n g of the l i g n i n o r i n t e r f i b e r bonding m a t e r i a l , facilitating of pulp.  f i b e r s e p a r a t i o n and t h e subsequent  soften-  thereby development  T h i s may g e n e r a l l y be a c h i e v e d t h r o u g h s t e a m o r  chemical pretreatment, o r a combination of both. shown by R y d h o l m  (79) t h a t a d e q u a t e  I t has been  c h i p p r e t r e a t m e n t has  b e n e f i c i a l e f f e c t s on f i b e r l e n g t h p r e s e r v a t i o n , a s w e l l as on t h e e n e r g y  requirement f o r f i b e r i z i n g the m a t e r i a l .  Chem-  i c a l pretreatments also affect the c h a r a c t e r i s t i c s of the resulting pulps i n the p o s i t i v e 1.  P r e t r e a t m e n t by  direction.  Steaming  The t e m p e r a t u r e  dependence o f m e c h a n i c a l  o f wood h a s b e e n d i s c u s s e d a t l e n g t h by R y d h o l m  properties  (79). In  t h i s book, i t was p o i n t e d o u t t h a t w e t t e r wood shows a l e s s marked temperature  dependence w h i l e t h e r e v e r s e c o n d i t i o n  exists  f o r t h e s w e l l i n g and r e s i d u a l e l a s t i c i t y p r o p e r t i e s o f  wood.  The e x p l a n a t i o n f o r t h e wood m e c h a n i c a l  strength-temp-  e r a t u r e r e l a t i o n may be b a s e d o n t h e s o f t e n i n g r a n g e o f l i g n i n w h i c h , a s q u o t e d by Rydholm range  329 t o 347°F  out a t t h i s ily  (79) a n d A t a c k  (165 t o 175°C).  (15), occurs i n the  I t i s necessary to p o i n t  j u n c t u r e t h a t t h e p r e s e n c e o f w a t e r may  a l s o depress o r broaden  necessar-  the softening i n t e r v a l of l i g n i n .  The erature  s o f t e n i n g e f f e c t o f w a t e r on wood a t room temp-  i s w e l l known a n d  i l l u s t r a t e d by  mechanical strength t e s t values wood.  As  i n d i c a t e d by  ivorensis  on  Iloabachie  the d i f f e r e n c e i n  s m a l l c l e a r specimens (45) w o r k i n g on  Terminalia  ( I d i g b o ) , w i t h the e x c e p t i o n o f impact bending r e -  sistance, a l l other  s t r e n g t h p r o p e r t i e s o f wood d e c r e a s e  an i n c r e a s e i n m o i s t u r e tion point  (fsp) range.  content  i n the  of the carbohydrate  zero to f i b e r  T h i s i s p o s s i b l y due  o f h y d r o g e n b o n d s w i t h i n t h e wood and  the  w a t e r does not  t e m p e r a t u r e s , h o w e v e r , t h e r e may  to the  seem t o h a v e a  79)^.  occur  At  presteaming  s p l i t t i n g of a c e t y l carbohy-  the much-debated l i g n i n - c a r b o h y d r a t e bonds w h i c h a l s o g l y c o s i d i c o r e t h e r bonds  bonds w h i c h are m a i n l y The  i n c i d e n c e of these  and  consequently  and  lignin  t u r e s b e l o w 212°F confirmed  the  r e s u l t s i n a decrease i n  Rydholm  i t s r a t e may  be  (100°C), i f pH  by K r a t z l a n d  degradation  (54, pH material  79).  (79), a c i d h y d r o l y s i s i s  a p p r e c i a b l e even a t is significantly  Paszner  of the  61,  are  intra-  b e n z y l - a l k y l e t h e r bonds  by m i l d a c i d h y d r o l y s i s (42, 54,  p H - d e p e n d e n t and  continuous  ( 6 1 ) ; and  a r a p i d r e m o v a l o f some c a r b o h y d r a t e  As p o i n t e d o u t by  was  splitting  significant  groups o f h e m i - c e l l u l o s e s a t t h e g l y c o s i d i c bonds of  lignin  satura-  subsequent s w e l l i n g  e f f e c t on wood a t n o r m a l room t e m p e r a t u r e .  probably  with  p o r t i o n s o f t h e wood.  Chemically,  dates;  of  ( 5 4 ) , who  tempera-  low.  This  showed t h a t a  l i g n i n macromolecule occurs  at  212°F  (100°C).  They b a s e d t h e i r f i n d i n g s o n t h e f a c t t h a t  monomeric b u i l d i n g u n i t s such as c o n i f e r y l a l d e h y d e , guaiacol,  t h e 3-ether and o t h e r m i n o r p r o d u c t s  vanillin,  were i s o l a t e d  f r o m wood a t a t e m p e r a t u r e o f 212°F (100°C). C e l l u l o s e tends t o r e s i s t a c i d h y d r o l y s i s b e t t e r than the hemicelluloses super-molecular  (61). This  i s due p r i m a r i l y t o t h e  s t r u c t u r e o f c e l l u l o s e because o f which  c e l l u l o s e i s n o t r e a d i l y a c c e s s i b l e even t o p o l a r despite i t s polarity. drate  However, t h e s w e l l i n g o f t h e c a r b o h y -  f r a c t i o n o f wood f o l l o w i n g t h e f o r m a t i o n  compounds o f c e l l u l o s e t e n d by  lysis,  nevertheless,  stance  and thus a d v e r s e l y  t o p o l a r reagents.  a f f e c t s the y i e l d of pulp.  degradation  c h i p s has been d i s c u s s e d  alkaline  during  result  i f c h i p s a r e i m p r e g n a t e d w i t h a weak  d r y wood w e i g h t p r e v e n t s the Na S0  3  I t has a l s o been  (42) t h a t a p p l i c a t i o n o f s o d i u m  (Na2S0 3) a t c o n c e n t r a t i o n s  2  The  t h e t r e a t m e n t o f wood  s o l u t i o n p r i o r t o presteaming.  the process,  hydro-  (NaHBi,) f o r t h e p u r p o s e o f  b y P i e t r o ( 7 5 ) . The same  shown b y H o g l u n d a n d B o d i n sulfite  Acid  c a u s e s a d e g r a d a d a t i o n o f t h e wood s u b -  a p p l i c a t i o n o f sodium borohydride  may a l s o be a c h i e v e d  of addition  t o "open up" t h e s t r u c t u r e , t h e r e -  enhancing i t s a v a i l a b i l i t y  c o n t r o l l i n g thermal  solvents  up t o 18% b a s e d o n bone  d i s s o l u t i o n o f woody m a t e r i a l . a c t s as a b u f f e r i n g a g e n t  autocatalytic action of organic  acids resulting  s p l i t t i n g o f a c e t y l s and u r o n i c a c i d s  f r o m wood.  In  against  from the  24. The  ultimate e f f e c t of presteaming pretreatment i s  to  reduce  f i b e r cleavage and thus p r e s e r v e f i b e r l e n g t h , and  to  cause r u p t u r e , p r e f e r e n t i a l l y on t h e o u t e r p a r t s o f t h e  fiber wall.  A compromise t e m p e r a t u r e  i s , however,  necessary  a s t o o h i g h a s o f t e n i n g t e m p e r a t u r e may c a u s e f i b e r s e p a r a t i o n to  take place i n the l i g n i n - r i c h middle  lamella  reducing the bonding p o t e n t i a l o f the f i b e r s . h a n d , l o w e r s o f t e n i n g t e m p e r a t u r e s may c a u s e separate a t the S i layer  A presteaming  the fibers to  l e n g t h , w h i l e , as p o i n t e d  e t a l . (41), enhancing temperature  On t h e o t h e r  ( 1 5 , 34, 4 1 , 60) t h e r e b y compro-  mising the preservation of fiber o u t by H o g l u n d  (ML) t h e r e b y  fiber.bonding potential.  o f 250 t o 260°F  g e n e r a l l y c o n s i d e r e d adequate  (121 t o 127°C) i s  f o r optimum s t r e n g t h d e v e l o p -  ment. As d e m o n s t r a t e d  b y G i e r t z . ( 3 5 ) , when s o f t e n e d a t t h e  high temperature p r e v a i l i n g i n the r e f i n i n g process, the p r i m a r y w a l l i s r o l l e d back a l o n g t h e f i b e r as a s l e e v e and s i m u l t a n e o u s l y t h e h e l i x o f t h e Si l a y e r c r a c k s a n d f i b r i l s and  lamellae are peeled o f f .  increased fiber f l e x i b i l i t y ,  This occurrence r e s u l t s i n w h i c h h a s b e e n shown b y F o r g a c s  (31) t o be an i m p o r t a n t f e a t u r e f o r s t r o n g m e c h a n i c a l p u l p s . T h i s i s so b e c a u s e t h e r e s u l t i n g r i b b o n s a n d f i b r i l s high bonding  have a  potential.  Presteaming pretreatment generally also r e s u l t s i n a darkening o f the pulp. Leask  However, as i n d i c a t e d by Keays and  ( 5 0 ) , and B y s t e d t and Vardheim  (23), t h i s  brightening  l o s s may  be c o n t r o l l e d by s u i t a b l y b a l a n c i n g t i m e and  ure d u r i n g the presteaming (15) and L e a s k  press-  o p e r a t i o n , o r , as q u o t e d by  Atack  ( 6 0 ) , by q u i c k l y r e d u c i n g t h e t e m p e r a t u r e  t h e p u l p as i t e m e r g e s f r o m t h e r e f i n e r .  of  Alternatively,  i n c o r p o r a t i n g a m i l d treatment w i t h a b r i g h t e n i n g agent some s t a g e o f t h e r e f i n i n g p r o c e s s w i l l lar  result.  2.  Chemical  also achieve a  at simi-  Pretreatment  V a r i o u s c h e m i c a l s a r e known t o a c h i e v e t h e d e s i r e d s o f t e n i n g o f t h e i n t e r - f i b e r b o n d i n g m a t e r i a l and  thereby  b r i n g a b o u t a more e f f i c i e n t f i b e r s e p a r a t i o n w i t h a minimum requirement  of energy.  Chemicals  are a b l e t o achieve  soft-  e n i n g o f i n t e r - f i b e r m a t e r i a l e i t h e r by d i r e c t l y c a u s i n g i t t o s o l u b i l i z e o r by t h e i r d i f f e r e n t i a l t h e wood s u b s t a n c e . softwood  The  swelling action  on  p u l p s from c h e m i c a l l y p r e t r e a t e d  c h i p s h a v e b e e n shown by H o g l u n d and B o d i n  t o have c o m p a r a b l e m e c h a n i c a l  (42)  strength properties to  those  of chemical pulps. The  b e s t r e s u l t s i n terms o f p h y s i c a l s t r e n g t h p r o -  p e r t i e s seem t o be t h o s e o b t a i n e d by t r e a t m e n t s w i t h hydroxides  ( 4 1 , 49,  86)  b e e n shown by B e e c h e r concentration.  e t a l . (20) t o i n c r e a s e w i t h  lignins.  degraded  alkali  hydroxides  f o r most forms o f c e l l u l o s e , and  v e n t s f o r m o d i f i e d and c e l l u l o s e s and  a n d t h e i m p r o v e m e n t i n s t r e n g t h has  T h i s i s mainly because a l k a l i  as s w e l l i n g a g e n t s  alkaline  forms o f c e l l u l o s e ,  as  act  sol-  hemi-  T r e a t m e n t w i t h an a q u e o u s s o l u t i o n o f s o d i u m h y d r o xide  (NaOH) h a s b e e n shown by K r u g e r e t a l . (55) a n d R y d h o l m  (79) t o h a v e a c o o k i n g a c t i o n on wood and t h u s r e s u l t s i n a y i e l d o f b e t w e e n 85 t o 94% on wood. c a u s t i c p r e t r e a t m e n t may  Yield  loss  following  a l s o be e x p l a i n e d by t h e f a c t  a l k a l i n e h y d r o l y s i s o f m o n o x i d i z e d c e l l u l o s e may the of  result i n  s p l i t t i n g o f f o f one g l u c o s e u n i t a t a t i m e i n t h e f o r m saccharinic acid  ( p e e l i n g ) , o r i n a random  cleavage o f the a c e t y l linkage i n c e l l u l o s e  hydrolytic  (61).  c o n d i t i o n i s f a v o r e d a t t e m p e r a t u r e s o v e r 15 8°F the  that  latter  The  former  (70°C), w h i l e  i s f a v o r e d a t t e m p e r a t u r e s above 302°F  (150°C),  such as i s e n c o u n t e r e d i n t h e s u l f a t e p u l p i n g p r o c e s s . l o s s due t o d e g r a d a t i o n o f c a r b o h y d r a t e and l i g n i n  Yield  fractions  by a c i d h y d r o l y s i s a t e l e v a t e d t e m p e r a t u r e s h a s b e e n d i s c u s s e d e a r l i e r under the e f f e c t o f presteaming p r e t r e a t m e n t . C a u s t i c p r e t r e a t m e n t i s g e n e r a l l y a c c o m p a n i e d by a r a p i d s w e l l i n g o f t h e wood. to  The s w e l l i n g i s , h o w e v e r ,  limited  t h e c a r b o h y d r a t e f r a c t i o n as l i g n i n t e n d s t o r e s t r i c t i t .  This swelling d i f f e r e n t i a l r e s u l t s  i n the b u i l d - u p of c o n s i d -  e r a b l e s t r e s s e s w i t h i n t h e f i b e r s t r u c t u r e , and f o l l o w i n g t h e k n e a d i n g a c t i o n o f t h e r e f i n i n g p r o c e s s , t h e more outer p o r t i o n s of the f i b e r ,  a l r e a d y under t e n s i o n , p e e l o f f .  T h i s amounts t o i n c r e a s e d f i b e r the  lignified  flexibility  and a l s o exposes  more h y d r o p h y l i c c a r b o h y d r a t e p a r t s w h i c h h a v e b e e n shown  by F o r g a c s bonding  (31), Giertz  potential.  (35) a n d R y d h o l m  (79) t o h a v e g o o d  I n a s i m i l a r manner, treatment,  as n o t e d  a l k a l i pretreatment  f o r the  presteaming  usually also results i n pulp  d i s c o l o r a t i o n r a n g i n g from p a l e y e l l o w t o dark brown. r e s u l t i n g pulps consequently f a c t o r y b r i g h t n e s s may  A  satis-  be a c h i e v e d w i t h a s i n g l e s t a g e  appli-  c a t i o n of sodium p e r o x i d e  n e e d t o be b r i g h t e n e d .  The  (Na202)/ c a l c i u m h y p o c h l o r i t e  ( C a ( O C l ) ) , o r sodium h y p o c h l o r i t e (NaOCl); 2  o r by i n c o r p o r a t -  i n g a b r i g h t e n i n g a g e n t a t some s t a g e i n t h e r e f i n i n g  process.  T h i s adds t o t h e c o s t o f p r o d u c t i o n , b u t t h e g a i n s i n p u l p q u a l i t y and t h e e x p e c t e d  s a v i n g s i n energy  justify  The e f f e c t o f c h e m i c a l  t h e added c o s t .  requirement  pretreatment  o n t h e c h a r a c t e r i s t i c s o f open d i s c h a r g e and p r e s s u r e From t h i s t a b l e ,  tend to  p u l p s a r e shown i n T a b l e  IV.  that chemical treatment,  i n t h e case o f open d i s c h a r g e  refiner  i t i s evident refin-  i n g , r e s u l t e d i n h i g h e r d e n s i t y , s t r e n g t h and b r i g h t n e s s v a l ues, b u t d e c r e a s e d ing,  opacity.  I n the case o f p r e s s u r i z e d r e f i n -  t h e r e s u l t s a r e more d i f f i c u l t  t o i n t e r p r e t s i n c e the  pulps are a t d i f f e r e n t freeness l e v e l s .  I t seems,  however,  t h a t a l t h o u g h sodium s u l f a t e w o u l d have a modest e f f e c t strength characteristics,  on  i t h a s a n e g a t i v e e f f e c t on b r i g h t -  ness . S i g n i f i c a n c e of F i b e r Length The i m p o r t a n c e  and F i b e r F r a c t i o n s  of fiber  l e n g t h as a fundamental  factor  c o n t r o l l i n g t h e p h y s i c a l p r o p e r t i e s o f a p u l p has l o n g been recognized.  More r e c e n t , t h e s i g n i f i c a n c e o f some o t h e r  c h a r a c t e r i s t i c s has been c l a r i f i e d .  The r a t i o b e t w e e n  fiber  cell  28. lumen w i d t h  and  r a t i o of f i b e r shown by  c e l l w a l l t h i c k n e s s , and length to f i b e r width  Dinwoodie  a greater extent the  (28)  Regie I n d u s t r i e l l e  (aspect  to a f f e c t pulp  than f i b e r de  particularly  and  the  r a t i o ) have been  paper p r o p e r t i e s  length alone.  Investigations  la Cellulose Colonials  (RICC),  to  by on  W e s t A f r i c a n T r o p i c a l Woods, c i t e d by P e t e r i ( 7 3 ) , showed  that  no  ten-  r e l a t i o n e x i s t e d between the  sile  and  bursting strengths,  b e t w e e n t h e s e p r o p e r t i e s and of the  lengths  but  o f f i b e r s and  that relationships existed  the c o e f f i c i e n t s o f  flexibility  fibers. As  q u o t e d by  pointed  Forgacs  out  by P a n s h i n and  (31), f i b e r  de  Zeeuw ( 7 1 ) , and  length i s important  length i s required  bonding surface  f o r e f f e c t i v e s t r e s s d i s t r i b u t i o n over  e n t i r e area  of the  sheet.  The  to provide  offer less  t a n c e t o p u l l - o u t b e c a u s e s h o r t f i b e r s h a v e more f r e e ends per  u n i t volume o f In a review  p r o p e r t i e s , Forgacs  (31)  t h a n t e a r was  i n d i c a t e d t h a t t h e wet  s t r e n g t h and  web  burst strength, breaking  l e n g t h on  showed t h a t t h e e f f e c t o f  l e n g t h on p r o p e r t i e s o t h e r  c o u l d be  out  resisfiber  length, bulk  the  and  tearing  d e p e n d e n t on  further  strength,  a i r resistance  structural  predicted with considerable  strength  fiber  s e c o n d a r y and  l a b o r a t o r y h a n d s h e e t s made f r o m a w i d e r a n g e o f  and  the  pulp.  o f the e f f e c t of f i b e r  are almost w h o l l y  as  sufficient  same a u t h o r s a l s o p o i n t e d  t h a t paper c o n s i s t i n g o f short f i b e r s w i l l  as  insofar  a minimum f i b e r  pulps  the  of  mechanical composition,  accuracy from  the  L- a n d S - f a c t o r . T a b l e V. identify  T h i s was  Although  i l l u s t r a t e d by J a c k s o n  a number o f t e c h n i q u e s  a l e n g t h and shape f a c t o r ,  L - f a c t o r was d e f i n e d  c a n be u s e d t o  the Forgacs'  the Forgacs  1  Length p r  (31) a s t h a t f r a c t i o n o f p u l p  on t h e 48 mesh s c r e e n ' d u r i n g a B a u e r M c N e t t while  (46), i n  retained  fractionation,  Shape o r S - f a c t o r was d e f i n e d as t h e  h y d r o d y n a m i c s p e c i f i c s u r f a c e o f t h e 48/100 mesh  fraction.  From T a b l e V, r e f e r r e d t o a b o v e , i t i s c l e a r t h a t S - f a c t o r p l a y s a more s i g n i f i c a n t r o l e i n d e t e r m i n i n g p r o p e r t i e s o f SGW and  pulp  t h a n i n t h e c a s e o f TMP w h e r e b o t h L-  S - f a c t o r seem t o h a v e e q u a l  shows t h a t t h o s e potential,  the  importance.  The t a b l e a l s o  p r o p e r t i e s w h i c h d e p e n d on f i b e r b o n d i n g  f o r example, b u l k , b u r s t i n g s t r e n g t h , and  l e n g t h , p r i m a r i l y d e p e n d on S - f a c t o r , w h e r e a s t e a r  breaking  depends  p r i m a r i l y on L - f a c t o r . I n g e n e r a l , h o w e v e r , a number o f f a c t o r s c o m b i n e t o determine the f i n a l c h a r a c t e r i s t i c s of a pulp. c i t e d by S c h u t t  T h e s e , as  (81) i n c l u d e f i b e r d i m e n s i o n s , f i b e r  f i b e r c o n f o r m a b i l i t y , surface area,  swollen  specific  b o n d i n g a r e a , b o n d i n g s t r e n g t h p e r u n i t o f bonded d i s t r i b u t i o n o f bonds  strength, volume,  area,  ( s h e e t f o r m a t i o n ) , and s t r e s s  distribu-  tion. Pulp  Blending C l a s s i c a l chemical  tively  low y i e l d o f p u l p ;  pulping processes  consequently,  give a  the pulps  rela-  are expen-  s i v e a n d , t h e r e f o r e , h i g h - g r a d e f o r some c a t e g o r i e s o f u s e .  30. Furthermore, the mechanical g e n e r a l l y exceed those  pulps  pulps  have a v e r y s i g n i f i c a n t y i e l d  the chemical p u l p i n g processes,  but  the  a r e r e l a t i v e l y weak f o r m o s t a p p l i c a t i o n s .  p a r t i c u l a r l y t r u e i n the case of stone  p r o p e r t i e s i n the p o s i t i v e d i r e c t i o n of pulps, therefore, i s important,  advan-  This i s  groundwood p u l p .  (46, 9 1 ) .  Mech-  printing  The  blending  not o n l y i n making  able a material of a suitable q u a l i t y  Mech-  resulting  a n i c a l p u l p s , h o w e v e r , i n f l u e n c e p a p e r s u r f a c e and  duct, but  may  r e q u i r e d i n some p a p e r p r o d u c t s .  a n i c a l pulping processes tage over  p r o p e r t i e s of chemical  avail-  f o r a given paper  a l s o from the c o s t - s a v i n g p o i n t of view.  pro-  The  blending of Gmelina s u l f a t e pulp w i t h l o n g - f i b e r s u l f a t e p u l p s t o enhance t h e m e c h a n i c a l  strength properties of  f o r m e r had  Chittenden  been contemplated  by  P r i n t i n g papers are expected combination properties.  The  blending of chemical  f o r the p r o d u c t i o n of newsprint, c o n s i d e r a t i o n and by Wahren c a l and  compromise.  suitable  mechanical  and m e c h a n i c a l  t h e r e f o r e , demands  T h i s i s b e c a u s e , as  strength pulps careful illustrated  (91), t h e r e i s a c l o s e r e l a t i o n s h i p between mechani-  optical properties. P u l p b l e n d i n g may  be  achieved  d e p e n d i n g upon what c o n d i t i o n s a p p l y . improve the mechanical those  e t a l . (26).  to exhibit a  o f p r i n t a b i l i t y , p h y s i c a l and  the  i n a v a r i e t y o f ways, Where t h e a i m  strength of s h o r t - f i b e r pulps  o f l o n g - f i b e r p u l p s , t h e wood raw  i s to with  m a t e r i a l f o r the  31. different or may  t y p e s may  be b l e n d e d p r i o r t o p u l p i n g ( 3 2 , 39,  d u r i n g the b e a t i n g o p e r a t i o n . be b e a t e n  may  be u p . t o  cal pulp.  I n some c a s e s , t h e p u l p s  s e p a r a t e l y and t h e n b l e n d e d  component o f t h e n e w s p r i n t f u r n i s h 75 t o 80%,  The  (39).  The  major  i s mechanical pulp, which  t h e r e m a i n i n g 25 t o 20% b e i n g  p r o p o r t i o n s may,  h o w e v e r , be v a r i e d  ation  F o r example, Paper  of the P h i l i p p i n e s  produces  k r a f t pulp ods  (25).  The  application  antici-  Industries  n e w s p r i n t f r o m 100%  p u l p s u s i n g 60% r e f i n e r m e c h a n i c a l p u l p and  chemi-  depending  o n t h e p r o p e r t i e s o f t h e p u l p s t o be b l e n d e d , a n d / o r pated product q u a l i t y .  40%  Corporhardwood  semi-bleached  o f l i n e a r programming meth-  f o r a g r e a t e r e f f i c i e n c y o f b l e n d i n g o p e r a t i o n s was  c u s s e d by F o s t e r ( 3 2 ) .  76)  dis-  CHAPTER I I I EXPERIMENTAL WORK Introduction The e n t i r e r a n g e o f m e c h a n i c a l r e f i n i n g were p r o d u c e d  p u l p s o b t a i n a b l e by  f r o m G m e l i n a a r b o r e a Roxb., by  simu-  l a t i o n o f b o t h open d i s c h a r g e and p r e s s u r i z e d r e f i n i n g l a b o r a t o r y equipment. refining,  I n the case o f s i m u l a t e d p r e s s u r i z e d  t h r e e c o n d i t i o n s were used.  l a t e d c o n v e n t i o n a l TMP, c a l l y p r e t r e a t e d TMP  on  The f i r s t one  simu-  a n d t h e o t h e r two s i m u l a t e d c h e m i -  u s i n g NaOH i n o n e c a s e a n d N a S 0 2  3  in  the other. The p h y s i c a l p r o p e r t i e s o f a l l p u l p s w e r e e v a l u a t e d and  TAPPI s t a n d a r d h a n d s h e e t s w e r e p r o d u c e d  t i o n of mechanical energy  and o p t i c a l p r o p e r t i e s .  f o r the evaluaSince the s p e c i f i c  consumption i n r e f i n i n g and t h e d r a i n a g e c h a r a c t e r -  i s t i c s o f t h e p u l p s w e r e known, t h i s p e r m i t t e d  interpolation  of the p h y s i c a l property data t o a given l e v e l o f e i t h e r energy  input or drainage c h a r a c t e r i s t i c .  s i m i l a r d a t a w e r e a l s o o b t a i n e d on SGW  For  comparison,  pulps produced  on  t h e West C o a s t o f Canada for;.use i n n e w s p r i n t . As n e w s p r i n t 25%  chemical pulp  were a l s o produced and  i n North America  (kraft or sulfite)  generally consists of  a n d 75% SGW,  handsheets  from m i x t u r e s o f Gmelina m e c h a n i c a l  k r a f t pulp i n the r a t i o s  7 5 : 2 5 , 80:20 a n d 8 5 : 1 5 .  p r o p e r t i e s o f t h e s i m u l a t e d n e w s p r i n t h a n d s h e e t s were 32  pulp The then  compared t o t h o s e o f handsheets a n d SGW.  produced  f r o m West C o a s t  However, s i n c e t h i s s i t u a t i o n i m p l i e s t h a t a  p r o d u c i n g such n e w s p r i n t would operate w i t h market (which i s e x p e n s i v e and would, profitability  therefore, affect  pulp.  To c o v e r t h i s p o s s i b i l i t y ,  source of  Source  the mechanical  Gmelina  wood u s e d  chemical  f o r both  the  Storage  f o r the present study  grown i n t h e f o r m e r M i d - W e s t e r n p a r t o f N i g e r i a , known a s B e n d e l S t a t e o f N i g e r i a . t i o n o f a sample used  I t was  currently  the remaining  measuring  a b o u t 2.4  meters  l o n g and  15 t o 25 cm  unbarked  i n Vancouver i n good c o n d i t i o n , e x h i b i t i n g  (6 t o 10 i n c h e s ) d i a m e t e r  m o i s t u r e c o n t e n t o f 95%.  The  the Western F o r e s t Products Laboratory m o i s t u r e c o n t e n t was  was  por-  i n an e a r l i e r s t u d y i n E a s t e r n Canada.  Logs o f Gmelina  average  con-  pulp.  o f M a t e r i a l s and M a t e r i a l s The  mill  a t h i r d set of simulated  n e w s p r i n t s h e e t s w e r e made u s i n g G m e l i n a c h e m i c a l p u l p and  mill  SBK  a d v e r s e l y ) , t h e a l t e r n a t i v e w o u l d be t o  s i d e r an i n t e g r a t e d m i l l w i t h i t s own  SBK  (8 f e e t )  arrived an  l o g s were s t o r e d a t (WFPL) a n d  m a i n t a i n e d by s p r i n k l e r  their  irrigation  u n t i l t h e y were r e q u i r e d f o r c h i p p i n g . C h i p p i n g and C h i p  Handling  P r i o r t o c h i p p i n g , t h e l o g s were d e b a r k e d a n d c u t i n t o 0.6 governed  t o 0.9  meter  manually  (2 t o 3 f o o t ) s e c t i o n s ,  by s u c h f e a t u r e s as p r o m i n e n t  knots or  as  crookedness.  E a c h s e c t i o n was t h e n s p l i t a x i a l l y axe  i n t o f o u r p i e c e s w i t h an  and a c l u b t o p r o v i d e m a t e r i a l h a v i n g  s u i t a b l e dimensions  for the preparation of chips. Chipping  was c a r r i e d o u t a t t h e B r i t i s h  I n s t i t u t e o f Technology diameter, chips.  two-knife,  (BCIT),  v e r t i c a l gyratory motion. carded 76%  Mechanical  using a chip screen with a  F i n e s and o v e r s i z e c h i p s were b a g s a t 42°F  dis-  (6°C) a n d  humidity.  Pulping  Hardwoods i n g e n e r a l softwoods and consequently  have s h o r t e r f i b e r l e n g t h s  than  have b e e n u s e d t o a much l e s s e r  i n SGW p u l p m a n u f a c t u r e .  be a r e a s o n a b l e but  30 i n  s e t t o p r o d u c e 5/8 i n l o n g  and.accepts stored i n polythene  relative  extent  u s i n g an e x p e r i m e n t a l ,  CAE c h i p p e r ,  The c h i p s were s c r e e n e d  Columbia  Open d i s c h a r g e  refining  may  a l t e r n a t i v e f o r mechanical p u l p i n g o f Gmelina  t h e poor bonding p o t e n t i a l o f such pulps would l i m i t the  extent  t o w h i c h t h e p u l p p o t e n t i a l s t r e n g t h m i g h t be r e a l i z e d  The b e s t a p p r o a c h , t h e r e f o r e , a p p e a r s t o be TMP, p o s s i b l y i n conjunction with chemical Although available  pretreatment.  a s u i t a b l e p i l o t p l a n t f o r TMP was n o t  f o rthe present  study,  a reasonable  approximation  o f TMP was a t t e m p t e d by p r e s t e a m i n g t h e c h i p s i n an e x p e r i m e n t a l d i g e s t e r a n d t h e n r a p i d l y t r a n s f e r r i n g them t o a 1 2 i n c h S p r o u t Waldron l a b o r a t o r y open d i s c h a r g e had  refiner,  which  p r e v i o u s l y been h e a t e d t o t h e b o i l i n g p o i n t o f w a t e r .  35. The e x p e r i m e n t a l w o r k was c a r r i e d o u t t o c o v e r t h e e n t i r e range  o f pulps capable o f being produced  by r e f i n i n g .  Thus,  b o t h open d i s c h a r g e and p r e s s u r i z e d r e f i n i n g were s i m u l a t e d . I n t h e l a t t e r c a s e , t h e e f f e c t o f c h e m i c a l p r e t r e a t m e n t was also evaluated. The v a r i o u s t r e a t m e n t s c a r r i e d o u t a r e o u t l i n e d i n T a b l e VI... I n e a c h c a s e , t h e e q u i v a l e n t w e t w e i g h t o f 908 g (2 l b ) bone d r y w e i g h t izing.  o f c h i p s was t r e a t e d p r i o r t o f i b e r -  A s many r e f i n e r p a s s e s  as were n e c e s s a r y t o o b t a i n  pulps having s i m i l a r drainage c h a r a c t e r i s t i c s t o those o f SGW p u l p s u s e d (Csf)  i n the manufacture  (46) w e r e made i n e a c h  r e f i n e r passes  o f n e w s p r i n t , 100 ± 2 0 m l  case.  As r e f i n i n g  proceeded,  t o be s t u d i e d i n d e t a i l w e r e i d e n t i f i e d a n d  s u f f i c i e n t amounts o f p u l p s r e p r e s e n t i n g them w e r e for  withdrawn  study.  Pulp Evaluation 1.  Latency  Removal  Latency r e f e r s t o the presence  of latent strength i n  r e f i n e r p u l p s and a r i s e s as a r e s u l t o f a c o m b i n a t i o n o f h i g h l y k i n k e d and c u r l e d f i b e r e x i t i n g from a h o t r e f i n e r and e x p e r i e n c i n g t e m p e r a t u r e to the temperature  shock  (46) .  The s h o c k  d i f f e r e n c e between t h e r e f i n i n g  the r e f i n e d stock chest.  relates zone and  The k i n k e d f i b e r s t e n d t o s e t i n  t h e i r c u r l e d c o n d i t i o n and a r e unable degree o f o p t i c a l c o n t a c t o r bonding  t o a c h i e v e t h e same as they would i f they  were s t r a i g h t e n e d o u t .  L a t e n c y may a l s o r e s u l t i f t h e p u l p  is dried  a s shown b y S k e e t a n d A l l a n ( 8 2 ) .  t o any degree,  Pulps e x h i b i t i n g potential  l a t e n c y only e x h i b i t p a r t of t h e i r  s t r e n g t h and, t h e r e f o r e , r e q u i r e r e v i v a l by a  d i s p e r s i o n o p e r a t i o n a t high temperature. by S k e e t a n d A l l a n at  85°F  full  lasted 2.  i s sufficient to  potential strength. l a t e n c y removal  o p e r a t i o n d e s c r i b e d a b o v e was  c a r r i e d o u t on t h e Gmelina m e c h a n i c a l 85°F  demonstrated  t h e k i n k e d f i b e r s and thus p e r m i t a p u l p t o e x h i b i t  The  of  As  ( 8 2 ) , a 15 m i n (1,800 r e v ) d i s i n t e g r a t i o n  (29°C) i n a s t a n d a r d d i s i n t e g r a t o r  straighten its  full  pulps a t a  (29°C) u s i n g a s t a n d a r d d i s i n t e g r a t o r .  temperature The o p e r a t i o n  15 m i n .  Debris  Content  Following hot disintegration, on a 150-mesh f l a t content.  t h e p u l p s were  screened  s c r e e n f o r measurement o f d e b r i s o r r e j e c t  This property i s g e n e r a l l y expressed  as a  and p r o v i d e s a n i n d i c a t i o n o f how w e l l p r e t r e a t m e n t  percentage and r e f i n -  i n g o p e r a t i o n s have s e p a r a t e d t h e i n d i v i d u a l f i b e r s i n t h e wood.  The d e b r i s c o n t e n t s o f t h e d i f f e r e n t p u l p s a m p l e s a r e  given i n Table V I . 3.  Freeness Freeness,  though d i f f i c u l t  to define, i s a standard  p u l p t e s t t h a t p r o v i d e s an i n d i c a t i o n o f t h e d r a i n a g e a c t e r i s t i c s o f a suspension o f f i b e r s .  char-  As p o i n t e d o u t ( 6 1 ) ,  and  a s q u o t e d by K w e i and  Garceau  (5 6 ) , i t i s m a i n l y  ure of the f i n e s which passed through The  value obtained  approximation,  from the f r e e n e s s  inversely  the  200-mesh  a measscreen.  test i s , to a  first  p r o p o r t i o n a l t o the bonding  poten-  t i a l of a pulp. F r e e n e s s t e s t i n g was  c a r r i e d out i n accordance w i t h  T227os-58 o f TAPPI S t a n d a r d s The  (88), u s i n g a freeness  r e s u l t o f the t e s t i s termed Canadian s t a n d a r d  (Csf),  and  drainage  i s generally reported i n m i l l i l i t e r s  freeness  (ml).  The  c h a r a c t e r i s t i c s of the pulps produced d u r i n g  this  i n v e s t i g a t i o n w e r e m e a s u r e d by are g i v e n i n Table 4.  tester.  f r e e n e s s t e s t s and  these  data  VI.  Yield With the steady  decrease i n the a v a i l a b i l i t y  pulpwood, y i e l d o f p u l p from the c u r r e n t l y  of  used p u l p i n g  pro-  cesses  i s b e c o m i n g more and more a c r i t i c a l c o n s i d e r a t i o n .  Yields  from the d i f f e r e n t p r e t r e a t m e n t s ,  w e i g h t o f c h i p s a s was mechanical way  d u r i n g the manufacture  of  p u l p s , were d e t e r m i n e d f o r c h i p s t r e a t e d i n the  given i n Table VI.  treatment  refined  u s i n g t h e same d r y  was  pulped  i n g p u l p w a s h e d and o v e r n i g h t a t 221°F  A known w e i g h t o f c h i p s f r o m e a c h  separately i n a blender made i n t o a p a d .  (105°C).  Y i e l d was  bone d r y w e i g h t o f c h i p s p u l p e d . determination  The  are a l s o given i n Table  The  and  pads were  calculated results of VI.  the  resultdried  based yield  on  38.  5.  F i b e r Length The  fractions  Classification  importance o f f i b e r  l e n g t h and f i b e r  i n t h e d e t e r m i n a t i o n o f p u l p c h a r a c t e r i s t i c s has  been d i s c u s s e d i n an e a r l i e r s e c t i o n . was  length  Fiber  classification  c a r r i e d o u t i n a c c o r d a n c e w i t h T 2 3 3 o s - 7 5 o f TAPPI S t a n -  dards  (88), u s i n g a Bauer-McNett  Classifier.  w e r e R 1 4 , 1 4 / 2 8 , 28/48, 48/100 a n d 1 0 0 / 2 0 0 .  Screen  sizes  Average  fiber  l e n g t h measurements, f o r t h e s c r e e n f r a c t i o n s , were  carried  o u t b y means o f a p r o j e c t i o n m i c r o s c o p e , a n d t h e i r m o i s t u r e f r e e w e i g h t s were d e t e r m i n e d . calculated  from t h e r e l a t i o n _  Where 11, Z , 2  fibers  Wi&i  +  W3&3 ^  5  fiber  length  ( L ) , was  (88): + wi+A i> +  W5&5 •  a r e t h e average  i ntherespective  from each 5  W2&2  £ 3 , £ it a n d £  Wi, W 2 , w  w  +  Weighted  l e n g t h s i n mm o f  fractions,  a n d wi* a r e t h e m o i s t u r e - f r e e w e i g h t s o f p a d s  3  f r a c t i o n , and  i s o b t a i n e d , by d i f f e r e n c e ,  from t h e r e l a t i o n :  .W = o r i g i n a l m o i s t u r e - f r e e w e i g h t o f p u l p  sample  classified. The  r e s u l t s o f t h e Bauer McNett c l a s s i f i c a t i o n o f t h e d i f f e r -  ent types o f pulp a r e given i nTable V I I , w h i l e i nFigures 4 through 7 photomicrographs  o f t h e p u l p s a r e shown.  As n o t e d a b o v e , F o r g a c s h a s i n d i c a t e d  t h a t most o f  t h e p h y s i c a l p r o p e r t i e s o f m e c h a n i c a l p u l p s c a n be r e l a t e d t o the s o - c a l l e d L-and S - f a c t o r s ( 3 1 ) .  The d e t e r m i n a t i o n o f  L - f a c t o r i s b a s e d o n t h e B a u e r - M c N e t t l o n g f i b e r , R48, f r a c tion, while  S - f a c t o r i s q u o t e d as t h e f r e e n e s s  M c N e t t P48/100 f r a c t i o n . determined.for are given Sulfate  the pulps  i n Table  The v a l u e s o f L ~ a n d  o f the BauerS-factors  produced during these i n v e s t i g a t i o n s  VIII.  Pulping Sulfate o r k r a f t pulping involves the d i g e s t i o n of  wood u n d e r a l k a l i n e c o n d i t i o n s . s u l f a t e p u l p i n g was e v a l u a t e d  The r e s p o n s e o f G m e l i n a t o  i n t h e l a b o r a t o r y by d i g e s t i n g  t h e e q u i v a l e n t o f 4.0 k g (8.8 l b ) bone d r y w e i g h t o f c h i p s under t h e f o l l o w i n g c o n d i t i o n s : L i q u o r t o wood r a t i o Active alkali  i n white  4:1 liquor  A c t i v e a l k a l i o n wood  15.5%  Sulfidity  24.6%  Maximum t e m p e r a t u r e  338°F  Time t o maximum t e m p e r a t u r e  90 m i n  Time a t maximum t e m p e r a t u r e  120 m i n  These c o n d i t i o n s a r e comparable t o t h o s e (69)  14.7%  a n d E s t u d i l l o e t a l . (30) a s b e i n g  good q u a l i t y  (170°C)  i d e n t i f i e d by P a l m e r s u i t a b l e f o r producing  s u l f a t e pulp from Gmelina.  A t t h e t e r m i n a t i o n o f t h e c o o k , t h e d i g e s t e r was blown, and t h e p u l p washed and s c r e e n e d screen.  During  Chittenden  screening,  o n a 150-mesh  flat  some f o a m i n g was o b s e r v e d .  e t a l . ( 2 6 ) , e a r l i e r made a s i m i l a r  observation  40. and  a t t r i b u t e d i t to the high r e s i n content The  y i e l d o f p u l p was  j e c t content mainly 1.  was  2.65%.  of incompletely pulped  The  species.  the d e b r i s or  re-  rejects consisted  knots.  K a p p a Number o f S u l f a t e P u l p , The  in  as h i g h as  5 0 . 0 5 % , and  of the  Kappa number i s an i n d e x o f t h e r e s i d u a l  a chemical  pulp.  I t i s , t h e r e f o r e , a measure o f the  of d e l i g n i f i c a t i o n achieved convenient  lignin  i n a cook, and  degree  thus represents  a  base f o r the comparison of such p u l p c h a r a c t e r i z a -  t i o n p a r a m e t e r s as y i e l d ,  s c r e e n i n g s , b r i g h t n e s s and  other  physical properties.  determination of bleaching  chemicals  requirement,  The  particularly  f o r the i n i t i a l  chlorination  stage,  i s a l s o b a s e d on K a p p a number. As  d e f i n e d i n TAPPI S t a n d a r d s  i s t h e number o f m i l l i l i t e r s  o f O.IN  ( 8 8 ) , t h e K a p p a number  potassium  permanganate  (KMnOit) s o l u t i o n consumed p e r gram o f m o i s t u r e - f r e e p u l p  under  c o n d i t i o n s s p e c i f i e d i n the standard.  was  c a r r i e d out 16 was Rydholm  obtained  f o r the Gmelina k r a f t p u l p .  As  a value  percent  Semi-bleaching  residual  of  i n d i c a t e d by  (79)., f o r a h a r d w o o d s u l f a t e p u l p , t h i s v a l u e  The CEH  determination  i n a c c o r d a n c e w i t h T236m-6 ( 8 8 ) , and  s p o n d s t o 2.08 2.  The  corre-  lignin.  of Sulfate Pulp  s u l f a t e p u l p was  semi-bleached  in a  ( C h l o r i n a t i o n , E x t r a c t i o n and H y p o c h l o r i t e )  three-stage, bleaching  41. sequence.  A brightness of  d e t e r m i n e d a t 45 7 nm sheet,  was  a)  b a s e d on  w a v e l e n g t h on  the glazed  side of  hand-  C h l o r i n a t i o n Stage The  c h o i c e o f c h l o r i n e f o r use  the  f a c t t h a t c h l o r i n e and lignin  aqueous a l k a l i erature.  (partially  Chlorine-water  at a concentration of  added, w i t h s t i r r i n g ,  on  3.5 8% on  to the  as.a  the  pulp  i s generally  deter-  C h l o r i n e o r Permangan-  C h l o r i n e number r o u g h l y  c h l o r i n e demand e x p r e s s e d  o f r e s i n and,  capable  substitution in  other equivalent parameters.  C h l o r i n e number may,  was  i n w a t e r ) by r e a c t i o n a t room temp-  m i n e d by c o n s i d e r a t i o n o f K a p p a , Roe  ( 7 9 ) , Roe  stage  other halogens are  C h l o r i n e c o n c e n t r a t i o n on p u l p  a t e numbers o r any  in this  soluble through aromatic  d r y w e i g h t o f p u l p was  Rydholm  r e f l e c t a n c e , as  achieved.  of rendering  sample.  77 t o 80 E l r e p h o  As  cited  describes  the  percentage of the pulp.  h o w e v e r , be  i n f l u e n c e d by  the  by  Roe  presence  a c c o u n t o f t h i s , K a p p a number i s g e n e r a l l y  preferred. C h l o r i n a t i o n l a s t e d 50 m i n t e m p e r a t u r e was pulp  maintained  a t 70°F (21°C).  a f t e r c h l o r i n a t i o n and  d u a l l i q u o r had  a pH  o f 2.  t i o n of hypochlorous a c i d t i o n and  w a s h i n g was The  l o w pH  The  y i e l d of  96.5%, and i s due  the  the  to the  the  resi-  forma-  (HOC1) d u r i n g t h e l i g n i n s u b s t i t u -  excitation reactions  showed t h a t HOC1  during which time  (61, 77).  The  same w o r k s  i s a strong o x i d i z i n g agent f o r  cellulose  and  may c a u s e i t s o r g a n i c o x i d a t i o n , t h e r e b y  to a l k a l i n e degradation, not r e a d i l y occur  pulping  a l k a l i n e h y d r o l y s i s does  under normal c o n d i t i o n s o f b l e a c h i n g , b u t  w o u l d u n d e r more s e v e r e chemical  although  predisposing i t  c o n d i t i o n s s u c h a s may e x i s t  during  processes.  I t i s important  t o p o i n t o u t t h a t c h l o r i n e i s non-  s p e c i f i c under t h e p r e v a i l i n g c h l o r i n a t i o n c o n d i t i o n s and i t s a t t a c k o n c e l l u l o s e , w h i l e u n l i k e l y , c a n n o t be e x c l u d e d . o x i d i z e d c e l l u l o s e i s a t t a c k e d by c h l o r i n e , c a r b o n y l b o x y l g r o u p s a r e f o r m e d , a s shown i n F i g u r e of these (79)  The p r e s e n c e  ( 7 7 ) , a n d a r e b e l i e v e d t o h a v e an  e f f e c t on f u r t h e r r e a c t i v i t y o f g l y c o s i d i c  -CO,  and c a r -  g r o u p s i n g l y c o s i d e u n i t s h a s b e e n shown b y R y d h o l m  and o t h e r s  general,  8.  When  reactivity  increases with.the  important  linkages.  In  i n t r o d u c t i o n o f -OH,  a n d -COOH g r o u p s i n t o t h e a n h y d r o g l u c o s e u n i t .  This  c o n d i t i o n p r e d o m i n a t e s a t . p H 2 (77) l e a d i n g t o o x i d a t i v e random d e p o l y m e r i z a t i o n  of individual cellulose  chains.  Together with l o s s o f f i n e s during pulp washing a f t e r c h l o r i n a t i o n , t h i s accounts f o r the l o s s o f y i e l d a f t e r the c h l o r ination b)  stage. E x t r a c t i o n Stage E x t r a c t i o n was c a r r i e d o u t u s i n g s o d i u m  hydroxide  (NaOH) s o l u t i o n a t a c o n c e n t r a t i o n o f 2.14% o n p u l p . was c o n t i n u e d  Stirring  throughout the e x t r a c t i o n p e r i o d o f 2 0 min,  d u r i n g w h i c h t i m e t h e t e m p e r a t u r e was m a i n t a i n e d  constant  at  149°F  (65°C). The  The y i e l d was 97.2%. a l k a l i c h a r g e f o r e x t r a c t i o n g e n e r a l l y depends  on t h e e f f i c i e n c y o f t h e p r e c e d i n g chlorolignin. ered  wash i n r e m o v i n g HC1 a n d  I n c o m m e r c i a l o p e r a t i o n , Rydholm  a c o n c e n t r a t i o n o f 20 t o 25 k g (9 t o 11 l b ) o f NaOH p e r  ton o f pulp fite  t o be a n o r m a l c h a r g e f o r b o t h s u l f a t e a n d s u l -  pulps. c)  Hypochlorite Calcium  Stage  hypochlorite  t r a t i o n o f 0.25% o n p u l p .  (Ca(OCl)2)  The s t a g e  was u s e d a t a c o n c e n -  l a s t e d 9 0 min d u r i n g  w h i c h p e r i o d t h e t e m p e r a t u r e was m a i n t a i n e d The  (79) c o n s i d -  a t 95°F  (35°C).  p u l p was s t i r r e d t h r o u g h o u t t h e e n t i r e p e r i o d a n d t h e  r e s u l t i n g y i e l d was 9 9 . 3 % . Handsheet Making and E v a l u a t i o n The  general p r i n c i p l e s concerning,  and t h e v a r i a b l e s  a f f e c t i n g t h e p r e p a r a t i o n o f l a b o r a t o r y h a n d s h e e t s have been e x h a u s t i v e l y d i s c u s s e d by S c h u t t Handsheets were p r e p a r e d accordance w i t h T205os-71 sheet machine. sheets  81).  during the i n v e s t i g a t i o n i n  (88), u s i n g a Standard B r i t i s h  I n t h e case o f . t h e mechanical p u l p s ,  Hand-  t h e hand-  were p r o d u c e d a f t e r t h e p u l p s had been h o t d i s i n t e -  grated. 5%  (80,  The h a n d s h e e t s w e r e p r o d u c e d a t a w e i g h t o f 1.20 g ±  (moisture-free basis),  60 g/m . 2  corresponding  t o a basis weight o f  S h e e t c o n d i t i o n i n g was c a r r i e d o u t a t 50.0 ± 2.0% RH  and  73.4 ± 1.8°F  (23.0 ± 1.0°C).  A l l w e i g h i n g and  e x c e p t w e t web s t r e n g t h t e s t i n g , was c a r r i e d tioning  room.  TAPPI s t a n d a r d p r o c e d u r e s  testing,  out i n the condi-  were adopted a l l  through. In made.  t h e case o f each p r o p e r t y , t e n o b s e r v a t i o n s were  The c a l c u l a t i o n s w e r e b a s e d  the Appendix. VI,  The r e s u l t s  on t h e f o r m u l a s g i v e n i n  of these t e s t s  I X , X, X I , X I I a n d X I I I .  are given i n Tables  CHAPTER I V RESULTS AND DISCUSSION M e c h a n i c a l P u l p s from  Gmelina  Data generated  from t h e t e s t i n g o f l a b o r a t o r y hand-  s h e e t s , made f r o m t h e G m e l i n a  mechanical  given i n Table V I , f o r t h e mechanical properties.  pulps produced a r e  s t r e n g t h and o p t i c a l  The v a l u e s o b t a i n e d f o r t h e v a r i o u s p h y s i c a l  p r o p e r t i e s were p l o t t e d a g a i n s t t h e i r r e s p e c t i v e d r a i n a g e characteristics.  Because a meaningful  comparison  ofthe  p h y s i c a l p r o p e r t i e s o f t h e v a r i o u s t r e a t m e n t s c a n o n l y be made under c o n d i t i o n s o f e q u i v a l e n t drainage o r e q u i v a l e n t energy a p p l i c a t i o n , the values a t a given l e v e l o f drainage C s f ) were d e t e r m i n e d data,.and  (90 m l  by i n t e r p o l a t i o n from t h e e x p e r i m e n t a l  a r e g i v e n i n Table  represents a-reasonable  I X . A f r e e n e s s o f 90 m l C s f  drainage l e v e l f o rNorth  mechanical p u l p s i n t e n d e d f o r use i n newsprint  American manufacture.  Various aspects o f the mechanical pulps prepared are discussed  below.  Yield Compared t o t h e y i e l d v a l u e s o f c h e m i c a l p u l p s , which  a r e g e n e r a l l y i n t h e range  4 0 t o 5 0%,  mechanical  pulps  e x h i b i t y i e l d s i n e x c e s s o f 90%, v a r i a t i o n s about t h i s  level  b e i n g g e n e r a l l y r e l a t e d t o wood c o m p o s i t i o n , p r e s e n c e o f e x t r a c t i v e s and p r e t r e a t m e n t .  The l a r g e d i f f e r e n c e i n y i e l d  b e t w e e n c h e m i c a l a n d m e c h a n i c a l p u l p s i s due t o t h e f a c t t h a t  w h i l e chemical pulps are produced  by p r o c e s s e s  g r a d a t i o n and s o l u b i l i z a t i o n o f l i g n i n , l i g n i n remains  i n v o l v i n g de-  i n mechanical  pulps,  an i n t e g r a l p a r t o f t h e f i b e r c h e m i c a l  struc-  ture . In Table V I , the y i e l d s f o l l o w i n g the d i f f e r e n t treatments are given.  chip  A y i e l d o f 9 6 . 8 % was o b t a i n e d f o r t h e  u n t r e a t e d s a m p l e , A, a n d 9 5 . 7 % f o r t h e p r e s t e a m e d s a m p l e , B. The  1% difference i n y i e l d  f o r t h e s e two c a s e s may be due t o  the f a c t t h a t , w h i l e i n both cases f i n e s were l o s t , was,  possibly,  steaming  some w a t e r  s o l u b l e s and  i n B a n a d d i t i o n a l ' l o s s o f wood  s u s t a i n e d through  temperatures.  substance  acid hydrolysis a t the pre-  The l o w y i e l d o f 8 9 . 6 % r e c o r d e d f o r  t h e c a u s t i c - t r e a t e d s a m p l e , C, was due t o t h e c o o k i n g  action  o f c a u s t i c o n wood, a n d i s p a r t l y r e s p o n s i b l e f o r t h e r e l a t i v e l y high strength values obtained f o r the caustic-treated sample.  Y i e l d was r e l a t i v e l y h i g h e r f o r t h e s u l f i t e  c h i p s , D, 9 5 . 3 % , n o t o n l y b e c a u s e i n c o m p a r i s o n  treated  to caustic,  s o d i u m s u l f i t e h a s o n l y a m i l d c o o k i n g a c t i o n on wood, b u t . a l s o b e c a u s e a t c o n c e n t r a t i o n s o f Na2SC>3 up t o 1 8 % , i t a c t s as a b u f f e r i n t h e s o l u t i o n , p r e v e n t i n g t h e d i s s o l u t i o n o f wood s u b s t a n c e ( 4 2 ) . S p e c i f i c Energy The  Consumption  manufacture  o f m e c h a n i c a l p u l p by d i f f e r e n t  c e s s e s i n v o l v e s e x p e n d i t u r e s o f l a r g e amounts o f e n e r g y . T a b l e V I t h e amounts o f e n e r g y  expended i n t h e manufacture  proIn of  mechanical pulps o f Gmelina a r e given, w h i l e i n Table I X , s p e c i f i c energy consumption t o a t t a i n  90 m l C s f i s g i v e n .  I t  i s e v i d e n t f r o m t h i s t a b l e t h a t more e n e r g y was r e q u i r e d i n t h e c a s e o f t h e c h e m i c a l l y p r e t r e a t e d c h i p s , 120 HPD/T f o r c a u s t i c a n d 113 HPD/T f o r s u l f i t e ,  t o o b t a i n p u l p s o f 90 m l  C s f , t h a n i n t h e c a s e s o f u n t r e a t e d open d i s c h a r g e r e f i n e r groundwood a n d steam p r e t r e a t e d r e f i n e r groundwood p u l p s , w h i c h r e q u i r e d 81 HPD/T a n d 9 3 HPD/T, r e s p e c t i v e l y . S t a t i s t i c a l a n a l y s i s o f the r e s u l t s given i n Table VI showed t h a t t h e c a u s t i c p r e t r e a t m e n t r e s u l t e d i n t h e b e s t mechanical strength properties. s h i p observed by Jensen t i o n between also exists  This confirms the r e l a t i o n -  (4 7 ) , a n d i m p l i e s t h a t t h e same  rela-  s p e c i f i c energy consumption and mechanical p u l p s f o r m e c h a n i c a l p u l p s made f r o m G m e l i n a wood.  J e n s e n ' s o b s e r v a t i o n , however, other treatments t r i e d .  d o e s n o t seem t o h o l d f o r t h e  F o r example,  t h e second  highest  s p e c i f i c e n e r g y c o n s u m p t i o n was n o t e d f o r t h e s u l f i t e p r e t r e a t e d s a m p l e , D, a n d y e t i t s m e c h a n i c a l p r o p e r t i e s , c o m p i l e d i n Table V I , a r e n o t s i g n i f i c a n t l y d i f f e r e n t from those o f t h e u n t r e a t e d s a m p l e , A, w h i c h consumed 40% l e s s e n e r g y , a n d t h e p r e s t e a m e d s a m p l e , B, w h i c h consumed 20% l e s s  energy.  S p e c i f i c energy consumption d u r i n g r e f i n i n g , i n g e n e r a l , d e p e n d s on a number o f f a c t o r s . o t h e r s , wood s p e c i e s c h a r a c t e r i s t i c s , r e f i n e r geometry  and feed f a c t o r s  These  include  among  type o f pretreatment,  ( 5 0 ) . The i n d i v i d u a l  e f f e c t s o f t h e s e f a c t o r s on energy consumption have n o t been  48.  c l e a r l y d e f i n e d and, consequently,  the a c t u a l  between energy consumption and the drainage  relationship  characteristics  of pulp i s not c l e a r .  Data r e l a t i n g these  t h e r e f o r e , be regarded  o n l y from the comparative  and not as a b s o l u t e  f a c t o r s should, standpoint  values.  Energy consumption i s g e n e r a l l y h i g h e r i n l a b o r a t o r y r e f i n i n g than f o r commercial r e f i n i n g t o the same  drainage.  T h i s i s p a r t l y because, w h i l e i t takes only two r e f i n e r passes to reduce c h i p s to the d e s i r e d drainage  l e v e l i n commercial  o p e r a t i o n s , i t takes f r e q u e n t l y up t o s i x o r more r e f i n e r passes t o a t t a i n the same drainage The  reason  f o r t h i s may be p a r t l y  using a laboratory  refiner.  due t o the d i f f e r e n c e s i n  c o n s i s t e n c y d u r i n g r e f i n i n g , and p a r t l y f a c t o r with the commercial o p e r a t i o n .  to a higher  efficiency  C o n s i s t e n c i e s i n the  range o f 20 t o 30% r e s u l t i n a s i g n i f i c a n t r e d u c t i o n i n power consumption  (50, 79), while as shown (11), a t lower c o n s i s -  t e n c i e s i t i s more d i f f i c u l t t o p u t l o a d i n t o the r e f i n i n g and  the a v a i l a b l e power i s not f u l l y u t i l i z e d .  study,  In the p r e s e n t  a l l r e f i n i n g was c a r r i e d out a t c o n s i s t e n c i e s between  9 and 13%, t h i s being the l i m i t o f c a p a b i l i t y laboratory r e f i n e r .  o f the s m a l l  T h i s i m p l i e s t h a t more energy than nece-  s s a r y may have been expended t o prepare the Gmelina mechanic a l p u l p s , and t h a t l e s s may be r e q u i r e d under commercial conditions.  Debris  Content The d e b r i s c o n t e n t o f p u l p s i s g e n e r a l l y  expressed  as t h a t p r o p o r t i o n o f t h e m a t e r i a l w h i c h i s r e t a i n e d on a s t a n d a r d s c r e e n p l a t e h a v i n g a s l o t w i d t h o f 150 standard screening conditions.  , under  I t generally consists of  i n c o m p l e t e l y s e p a r a t e d f i b e r s and f i b e r bundles,  and i t s  p a r t i c l e s a r e t h u s g r e a t e r t h a n one f i b e r d i a m e t e r Consequently,  i n width.  d e b r i s h a s a d e t r i m e n t a l e f f e c t on t h e p h y s i c a l  properties o f newsprint. ence i n m e c h a n i c a l  I t i s l a r g e l y because o f i t s p r e s -  pulps that a separate debris handling  s y s t e m i s n e c e s s a r y as an i n t e g r a l p a r t o f m e c h a n i c a l p u l p i n g process flow sheet. From T a b l e V I , t h e e f f e c t o f t h e v a r i o u s t y p e s o f p r e t r e a t m e n t s e m p l o y e d o n d e b r i s c o n t e n t may be  identified.  I t i s c l e a r from t h i s t a b l e t h a t the presteaming  pretreatment  caused a s i g n i f i c a n t r e d u c t i o n i n d e b r i s content over t i o n a l open d i s c h a r g e r e f i n i n g .  The t a b l e a l s o  conven-  indicates  t h a t chemical treatment caused a f u r t h e r decrease  i n debris  c o n t e n t , i n d i c a t i n g a more c o m p l e t e d e f i b e r i z a t i o n d u r i n g t h e refining. Mechanical Properties From d a t a i n T a b l e IX,  i t i s evident that a l l three  p r e t r e a t e d p u l p s e x h i b i t somewhat b e t t e r m e c h a n i c a l p r o p e r t i e s than those o f the n o n - t r e a t e d sample.  The t a b l e a l s o  indi-  cates, that the chemically treated pulps e x h i b i t better  char-  a c t e r i s t i c s t h a n t h o s e a c h i e v e d by p r e s t e a m i n g  I ti s  alone.  50.  assumed t h a t t h e  i m p r o v e d p r o p e r t i e s d e p e n d upon b o t h  l e n g t h p r e s e r v a t i o n and the pulp  fibers.  through  improved bonding c h a r a c t e r i s t i c s  This assumption i s confirmed  untreated  two  the  chemically  improved f i b e r reasoning  improved b u r s t The  l e n g t h and  i s the  This  i n t e r p r e t a t i o n of Forgacs  L-  1  i n Table IX t h a t the  causpro-  I f m a x i m i z i n g the m e c h a n i c a l s t r e n g t h were the that t h i s type of a l k l i n e  t h e most advantageous t o  only  pre-  use.  Properties Compared t o t h e n o n - p r e t r e a t e d  steamed and  caustic pretreated pulps  c o e f f i c i e n t s and, The  consequently,  consequently,  pulp,  both the  exhibit higher  coefficient,  on  the o t h e r  improved b r i g h t n e s s .  While the  exhibits a similar scattering coefficient,  (Table  hand,  compared t o t h e  pre-  absorption  decreased brightness  s u l f i t e pretreated pulp,  a decreased absorption  pulp  both  s a m p l e shows t h e g r e a t e s t g a i n i n s t r e n g t h  t r e a t m e n t w o u l d be  and  r e s u l t of  (31).  consideration, i t i s evident  IX).  length  improved bonding p o t e n t i a l .  I t i s c l e a r from the data tic-treated  of  strength i s entirely  improved breaking  treated pulps  i s i n l i n e w i t h the  S-Factors  perties.  the  sample i s d i r e c t l y r e l a t e d t o t h e p r e s e r v a t i o n  r e l a t e d to improved bonding.  Optical  4  by F i g u r e s  improved t e a r s t r e n g t h of a l l samples over  fiber length, while  and  of  7. The  of the  fiber  exhibits  control,  presteamed  both  c h e m i c a l l y - t r e a t e d pulps e x h i b i t decreased s c a t t e r i n g cients,  thus c l e a r l y  proved bonding  coeffi-  i d e n t i f y i n g t h a t t h e s e p u l p s have  im-  c h a r a c t e r i s t i c s over the untreated pulp.  fact i s also reflected  i n t h e s h e e t d e n s i t y w h i c h was  This  higher  f o r t h e s e p u l p s t h a n f o r t h e s t a n d a r d open d i s c h a r g e p u l p . Thus, i n terms  of brightness, s u l f i t e pretreatment  had t h e most b e n e f i c i a l e f f e c t , w h i l e t h e c a u s t i c had a s t r o n g l y d e t r i m e n t a l e f f e c t .  ,  treatment  However, i n v i e w o f  the  s t r o n g e f f e c t o f c a u s t i c t r e a t m e n t on p u l p s t r e n g t h p r o p e r ties,  i t would  seem a p p r o p r i a t e t o u s e t h i s  type of  treat-  ment t o m a x i m i z e t h e m e c h a n i c a l p r o p e r t i e s a n d o v e r c o m e t h e l o w e r b r i g h t n e s s by h y d r o g e n  peroxide treatment of the pulp.  A l t e r n a t i v e l y , a combined t r e a t m e n t w i t h c a u s t i c and s u l f i t e would  a i d s t r e n g t h improvement w i t h o u t s e v e r e  tion, of b r i g h t n e s s . ment and s u b s e q u e n t particular  sodium degrada-  Such o p t i m i z a t i o n o f c h e m i c a l p r e t r e a t b r i g h t e n i n g was  beyond the scope  of  this  study.  C o m p a r i s o n o f West C o a s t Groundwood and C a u s t i c T r e a t e d . G m e l i n a P u l p I n T a b l e X, t h e c h a r a c t e r i s t i c s o f t h e G m e l i n a tic  caus-  t r e a t e d p u l p a t 90 ml C s f a r e c o m p a r e d t o t h o s e o f West  C o a s t s t o n e groundwood a t 84 m l C s f . table,  i t i s e v i d e n t t h a t , i n terms  mechanical pulps produced Gmelina  From t h e d a t a i n t h i s of strength p r o p e r t i e s ,  by the c a u s t i c p r e t r e a t m e n t  compare f a v o r a b l y w i t h West C o a s t s t o n e  of  groundwood.  52. From t h i s t a b l e , i t i s e v i d e n t treated pulp and  exhibited higher  o p a c i t y , but  SGW.  t h a t the Gmelina c a u s t i c tear, burst, breaking  l o w e r d e n s i t y and  Brightness,  outlined earlier,  a problem, but,  o v e r c o m e by m o d i f y i n g  o f p r e t r e a t m e n t t o a c o m b i n a t i o n o f c a u s t i c and fite,  o r by  using peroxide  Chemical Pulp The  sodium  as the  form  sul-  b r i g h t e n i n g p r i o r to papermaking.  from Gmelina p h y s i c a l and  bleached k r a f t Table XI.  length  s t r e t c h t h a n West C o a s t  however, r e p r e s e n t s t h i s c o u l d be  pre-  (SBK)  mechanical p r o p e r t i e s of the  semi-  pulp produced from Gmelina are g i v e n  From t h i s t a b l e , i t i s c l e a r t h a t t h e  s t r e n g t h p r o p e r t i e s o f SBK  from Gmelina are  l o w e r t h a n t h o s e o f West C o a s t SBK  in  physical  significantly  g e n e r a l l y produced  from  s o f t w o o d s , among w h i c h a r e D o u g l a s f i r and W e s t e r n h e m l o c k . Differences are  i n t h e m e c h a n i c a l p r o p e r t i e s o f t h e s e SBK  l a r g e l y due  istics,  to the d i f f e r e n c e s i n t h e i r  p a r t i c u l a r l y the  low  9 through The  T h e s e may  be  12.  brightness  w o u l d t h u s be  particularly  SBK  observed i n  of Gmelina k r a f t ,  as i n d i c a t e d i n  T a b l e X I , i s s u p e r i o r t o t h a t o f t h e West C o a s t Brightness  character-  f i b e r l e n g t h of the Gmelina  c o m p a r e d t o t h e West C o a s t SBK. Figures  fiber  pulps  counterpart.  a s t r o n g p o s i t i v e f e a t u r e of  i f i t w e r e t o be  Gmelina,  used i n f i n e paper f u r n i s h e s .  The  P o t e n t i a l of Gmelina The  t r i a l s was  Gmelina  Mechanical Pulps f o r Newsprint  mechanical p u l p used  t h a t produced  gave t h e b e s t m e c h a n i c a l  f o r the  newsprint  by t h e c a u s t i c p r e t r e a t m e n t as i t p r o p e r t i e s compared t o t h e  pretreatments investigated.  other  A n o v e r a l l summary o f t h e  dry  s t r e n g t h d a t a r e l a t i n g t o t h e s t u d y o f t h e s e s i m u l a t e d newsp r i n t m i x e s i s g i v e n i n T a b l e X I I and t h e wet are provided i n Table X I I I .  strength data  F i g u r e s 13 t h r o u g h  23 are  p l o t s of newsprint handsheet p r o p e r t i e s over the  the  chemical  pulp content. From t h e s e t a b l e s and  f i g u r e s the e f f e c t of  chemical  p u l p c o n t e n t on t h e m i x e d f u r n i s h s h e e t p r o p e r t i e s c a n identified.  The  r e l a t i o n s h i p between c h e m i c a l p u l p  and n e w s p r i n t h a n d s h e e t p r o p e r t i e s i s e s s e n t i a l l y  be  content  linear in  t h e c h e m i c a l p u l p r a n g e o f i n t e r e s t , t h e b r i g h t n e s s and s t r e n g t h c h a r a c t e r i s t i c s i n c r e a s i n g , as e x p e c t e d , w i t h i n c r e a s i n g chemical pulp content while the o p a c i t y together w i t h s c a t t e r i n g and a b s o r p t i o n c o e f f i c i e n t s e x h i b i t a r e d u c t i o n . In g e n e r a l , the data i n d i c a t e t h a t the s t r e n g t h p r o p e r t i e s of Gmelina  mechanical  p u l p m i x t u r e s compare f a v o r a b l y w i t h t h o s e  o f t y p i c a l West C o a s t n e w s p r i n t m i x t u r e s , whereas m i x t u r e s containing both mechanical  and  c h e m i c a l p u l p from  Gmelina  are l a c k i n g i n c e r t a i n aspects. The  low b r i g h t n e s s o f m i x t u r e s c o n t a i n i n g Gmelina  r e f i n e r mechanical  p u l p i s a d e f i c i e n c y w h i c h w o u l d have t o  be o v e r c o m e . which t h i s thesis,  A l t h o u g h t h e i d e n t i f i c a t i o n o f t h e manner i n  s h o u l d be a c h i e v e d i s b e y o n d  t h e scope o f  i t i s e v i d e n t t h a t t h i s d e f i c i e n c y c a n be  this  overcome  by a p p r o a c h e s w h i c h have b e e n s u g g e s t e d e l s e w h e r e i n t h e thesis.  CHAPTER V SUMMARY Mechanical pulps c o v e r i n g a broad capable o f being produced a t o r y from Gmelina  by s i m u l a t e d p r e s s -  u r i z e d r e f i n i n g e x h i b i t e d b e t t e r mechanical t h e open d i s c h a r g e r e f i n e d p u l p . i n one c a s e , s o d i u m s u l f i t e  ( 2 0 % o n wood) a n d , i n t h e o t h e r  ( 1 0 % o n wood) r e s u l t e d i n f u r t h e r I n terms o f t h e p h y s i -  strength properties the caustic treated pulp  favorably with typical  s t o n e groundwood p u l p  on t h e W e s t C o a s t o f N o r t h A m e r i c a The  p r o p e r t i e s than  Chip pretreatments u s i n g ,  improvements i n p u l p c h a r a c t e r i s t i c s . cal  steaming  investigated.  g e n e r a l , those pulps produced  case, sodium h y d r o x i d e  I n t h e case o f  t h e e f f e c t o f p r e t r e a t m e n t by  c h e m i c a l i m p r e g n a t i o n were In  of pulps  b y r e f i n i n g w e r e made i n t h e l a b o r -  a r b o r e a Roxb., a h a r d w o o d .  pressurized refining, and  spectrum  compared  manufactured  f o r use i n newsprint.  c a u s t i c t r e a t e d p u l p , however, e x h i b i t e d h i g h a d s o r p t i o n  c o e f f i c i e n t and c o n s e q u e n t l y  low b r i g h t n e s s .  represents a p o t e n t i a l problem  While  i n t h e commercial  this  use o f  t h i s type o f pulp i n newsprint, t h e d e f i c i e n c y i s surmountable e i t h e r by employing  hydrogen p e r o x i d e b r i g h t e n i n g treatment  i n c o n j u n c t i o n w i t h t h e r e f i n i n g o p e r a t i o n , o r by u s i n g a c o m b i n a t i o n o f c a u s t i c and sodium s u l f i t e To e v a l u a t e t h e s u i t a b i l i t y  pretreatment.  o f t h e Gmelina  refiner  g r o u n d w o o d f o r u s e a s t h e m a j o r component o f t h e n e w s p r i n t  furnish,  i t s b e h a v i o r i n a d m i x t u r e w i t h West C o a s t  b l e a c h e d k r a f t was  investigated.  c a l p u l p e q u i v a l e n t t o t h a t used p r o p e r t i e s of the mixed f u r n i s h  semi-  At a given l e v e l of  chemi-  i n standard newsprint, Gmelina  handsheets  the  were  found  t o be c o m p a r a b l e t o t h o s e o f West C o a s t n e w s p r i n t m i x t u r e s . O p t i m i z a t i o n o f the p r e t r e a t m e n t and r e s u l t i n Gmelina  pulps suitable  p r i n t at lower chemical pulp The  s t u d y was  f o r t h e p r o d u c t i o n o f news-  levels.  u s i n g market k r a f t as t h e c h e m i c a l p u l p  To c o v e r t h e c a s e f o r t h e i n t e g r a t e d m i l l , a l s o c a r r i e d out t o assess the response  t o k r a f t p u l p i n g and  mechanical pulp.  woods i n g e n e r a l , G m e l i n a  k r a f t was  Gmelina  kraft pulps.  were c l e a r l y r e f l e c t e d  p r o p e r t i e s of mixed f u r n i s h  compared t o  soft-  s i g n i f i c a n t l y weaker,  m e c h a n i c a l l y , than t y p i c a l North American  ratios.  brief  As e x p e c t e d , i n v i e w  t h e s h o r t e r mean f i b e r l e n g t h o f G m e l i n a  strength deficiencies  of  a  to evaluate the behavior of t h i s pulp i n  admixture w i t h Gmelina of  may  above s i t u a t i o n c l e a r l y r e p r e s e n t s the case o f a  non-integrated m i l l component.  r e f i n i n g process  handsheets  i n the  a t normal  Its  mechanical  mixture  CHAPTER VI CONCLUSIONS AND RECOMMENDATIONS Conclusions 1.  A wide v a r i e t y o f r e f i n e r mechanical p u l p s can be p r o duced from Gmelina arborea Roxb.  2.  C a u s t i c p r e t r e a t e d Gmelina r e f i n e r mechanical pulp has comparable mechanical p r o p e r t i e s t o West Coast stone groundwood used i n newsprint f u r n i s h e s , and i s , t h e r e f o r e , a l s o s u i t a b l e f o r use i n newsprint manufacture.  3.  The use o f c a u s t i c p r e t r e a t e d Gmelina r e f i n e r groundwood i n admixture w i t h softwood semi-bleached k r a f t i n normal newsprint r a t i o s  (3:1) r e s u l t e d i n mixed f u r n i s h hand-  sheets w i t h p r o p e r t i e s comparable  t o handsheets from  North American newsprint f u r n i s h e s . 4.  Newsprint f u r n i s h handsheets produced from mixtures o f Gmelina r e f i n e r pulp and Gmelina semi-bleached k r a f t e x h i b i t mechanical p r o p e r t i e s which a r e i n f e r i o r t o those of  s i m i l a r handsheets from. North American newsprint mix-  tures. Recommendations 1.  The s t r o n g p o t e n t i a l i n d i c a t i n g the s u i t a b i l i t y of chemic a l l y p r e t r e a t e d mechanical pulp from Gmelina arborea Roxb. f o r newsprint manufacture should be e x p l o i t e d .  2.  The extent o f Gmelina arborea Roxb. p l a n t a t i o n r e s o u r c e s i n N i g e r i a , coupled w i t h the r a p i d l y i n c r e a s i n g demand 57  58. f o r p a p e r and p a p e r b o a r d , c a l l  f o r development  programs  w h i c h c a t e r t o t h e n a t i o n ' s demand f o r f i b e r a n d  fiber  products. I n d i g e n o u s h a r d w o o d s p e c i e s s h o u l d be e v a l u a t e d f o r t h e i r p o t e n t i a l f o r u s e as s u p p l e m e n t a r y m a t e r i a l s f o r p u l p a n d p a p e r , and a d d i t i o n a l p l a n t a t i o n s  s h o u l d be  established  t o g u a r a n t e e r e g u l a r and a d e q u a t e . s u p p l y o f p u l p w o o d the  to  mills.  F u r t h e r w o r k s h o u l d be c o n d u c t e d t o o p t i m i z e t h e c h e m i c a l pretreatment f o r thermomechanical p u l p from  Gmelina  a r b o r e a Roxb. w i t h r e g a r d t o m e c h a n i c a l p r o p e r t i e s , particular  a t t e n t i o n s h o u l d be d i r e c t e d t o w a r d s  ing technology.  and  brighten-  BIBLIOGRAPHY * 1.  A b a y o m i , J.O. 1 9 7 4 . A s t u d y o f t h e g r o w t h o f f i v e permanent p l o t s o f Gmelina a r b o r e a i n t h e d e r i v e d Savanna zone. Paper 5 t h Annual Conference o f t h e Forestry Association of Nigeria. 24 p p .  2.  A d e m i l u y i , E.O. a n d Okeke, R.E. 1 9 7 3 . S p e c i f i c g r a v i t y a n d f i b e r c h a r a c t e r i s t i c s o f G m e l i n a a r b o r e a i n some Nigerian plantations. Paper 4 t h Annual Conference of the Forestry Association o f Nigeria. 10 p p .  3.  A l a d e , G.A. 1 9 7 3 . G m e l i n a P u l p / P a p e r P r o j e c t . State of Nigeria. ( U n p u b l i s h e d ) . 7 pp.  4.  A l l a n , R.S., S k e e t , C.W. a n d F o r g a c s , O.L. 1 9 6 8 . R e f i n e r groundwood from d e c i d u o u s s p e c i e s . Pulp P a p e r Mag. C a n . 69 ( 1 8 ) : 74-80.  * 5.  Western  A l m i n , K.E. a n d Ruvo, A.D. 1 9 6 8 . P o l y n o m i a l r e p r e s e n t a tion of pulp mixture properties. R e p r i n t Svensk P a p p e r s t i d n i n g 70: 24, 846-50.  6.  Anon, (n.d.) R e p o r t s o n o v e r s e a s t i m b e r s , No. 7. R e p o r t on a c o n s i g n m e n t o f G m e l i n a a r b o r e a Roxb. f r o m Gambia. FPRL C o n s i g n m e n t No. 1 3 5 9 . 8 p p .  7.  Anon. 1965. Gmelina a r b o r e a (Gmelina) F e d e r a l D e p a r t ment o f F o r e s t R e s e a r c h , I b a d a n . No. F P R L / 2 . 10 p p .  8.  Anon. 1968. F e a s i b i l i t y o f e s t a b l i s h i n g a p u l p and paper i n d u s t r y . R e p o r t t o t h e Government o f N i g e r i a . FAO Rome No. TA2529. 58 p p .  * 9.  Anon. 1975. I w o p i n p u l p and paper m i l l p r o j e c t . Pilot p l a n t p u l p and paper t r i a l s ( P r e l i m i n a r y Report). 16 p p .  10.  Anon. 1975. P u l p i n g and papermaking g r o w i n g p l a n t a t i o n wood s p e c i e s . MISC/75/31. 7 pp.  11.  Anon. 1975. Thermomechanical p u l p a c c o r d i n g t o t h e Defibrator process with special reference t o Eucalyptus saligna. O P a p e l , 36 ( 2 ) : 49-56.  12.  Anon. 1 9 6 4 . The s i l v i c u l t u r e o f G m e l i n a a r b o r e a Roxb. N y a s . Fmr. a n d F o r s t r , 6 ( 3 ) : 13-22.  * Not c i t e d i n t e x t . 59  properties of fastFAO Rome FO:  60. 13.  Anon. 1976. M e c h a n i c a l p u l p - a m u l t i u s a b l e commodity. S v e n s k P a p p e r s t i d n i n g 79 (10) : 2 9 9 - 3 0 3 .  14.  Anon. 1 9 7 7 . News a b o u t t e c h n o l o g y a n d b u s i n e s s . 60 ( 4 ) : 21-27.  15.  A t a c k , D. 1 9 7 2 . On t h e c h a r a c t e r i z a t i o n o f p r e s s u r i z e d r e f i n e r m e c h a n i c a l p u l p s . Svensk P a p p e r s t i d n i n g No. 3: 89-94.  16.  B a d e j o , S.O. 1977. U n i v e r s i t y o f B r i t i s h Columbia, Faculty of Forestry. (Personal communication).  17.  B a l l o n , C.H., E s c o l a n o , J.O., V i l l a n e u v a , E.P., T a d e n a , O.B., V i s p e r a s , R.V. a n d E s t u d i l l o , C P . 19 71. P r o s p e c t s o f Gmelina arborea f o r p u l p and p r i n t i n g papers. Philippine Forests. Espana. M a n i l a 5 ( 1 ) : 12-5.  18.  B a r b a d i l l o , P. 19 67. Summary o f S p a n i s h e x p e r i m e n t s o n t h e p u l p i n g o f E u c a l y p t u s . A p p i t a 21 ( 2 ) : 2 7-4 0.  19.  B e a u l i e u , S., K a r n i s , A., W i l d , A . J . a n d Wood, J.R. 19 77. Domtar i n s t a l l s TMP a t D o n n a c o n a n e w s p r i n t mill. P a r t I - D e s c r i p t i o n and o p e r a t i o n o f t h e system. P u l p P a p e r Mag. C a n . 78 ( 3 ) : T 6 1 - 5 .  20.  B e e c h e r , J . J . , H o f f m a n , G.R. a n d Swanson, J.W. 1 9 7 6 . Improved b o n d i n g i n groundwood f u r n i s h e s . T a p p i 59 ( 1 ) : 104-7.  21.  B e r g s t r o m , J . 1966. M e c h a n i c a l p u l p and r e f i n e r p u l p : a comparison. (PPRIC T r a n s l a t i o n S e r i e s No. 1 1 2 ) . 13 p p .  22.  B r o w n i n g , B.L. 1970. Wood C h e m i s t r y , B r i t t , K.W. e d . Handbook o f P u l p a n d P a p e r T e c h n o l o g y 2nd E d . V a n N o s t r a n d , R e i n h o l d , New Y o r k . p 3-12.  23.  B y s t e d t , I . a n d V a r d h e i m , S. 1 9 6 8 . R e f i n e r m e c h a n i c a l p u l p made a t e l e v a t e d t e m p e r a t u r e a n d p r e s s u r e . P a p e r T r a d e J o u r n a l 152 ( 1 6 ) ; 6 5 - 7 .  24.  Canada. 1974. S t a t i s t i c s C a n a d a . C a t a l o g u e 36-204 A n n u a l .  25.  C a v a n , E.C. 1 9 7 7 . P a p e r I n d u s t r i e s C o r p o r a t i o n o f t h e Philippines. ( P e r s o n a l communication):.  * Not c i t e d i n t e x t .  Pulp and Paper  Tappi  Mills.  26.  C h i t t e n d e n , A.E., C o u r s e y , D.G. a n d R o t i b i , J.O. 1964. Papermaking t r i a l s w i t h Gmelina arborea t i m b e r i n Nigeria. T a p p i 47 ( 1 2 ) : 1 8 6 - 1 9 2 .  27.  CPPA. 1976. Methods.  28.  D i n w o o d i e , J.M. 1965. The r e l a t i o n s h i p b e t w e e n f i b e r m o r p h o l o g y and p a p e r p r o p e r t i e s . A review of literature. T a p p i 48 ( 8 ) : 440-7.  29.  Enemuoh, P.O. 1970. The e s t a b l i s h m e n t a n d management of Gmelina p l a n t a t i o n s w i t h s p e c i a l reference t o Akpaka F o r e s t R e s e r v e , O n i t s h a . Paper 1st Annual Conference of the F o r e s t r y A s s o c i a t i o n of N i g e r i a . 10 p p .  30.  E s t u d i l l o , C P . , V i s p e r a s , R.V., B a l l o n , C.H., Tadena, O.B. a n d V i l l a n e u v a , E.P. 1972. Sulfate pulping s t u d i e s on Yemane ( G m e l i n a a r b o r e a R o x b . ) . P h i l i p p i n e Lumberman 18 ( 4 ) : 18-23.  31.  F o r g a c s , O.L. 1963. The c h a r a c t e r i z a t i o n o f m e c h a n i c a l pulps. P u l p P a p e r Mag. Can., C o n v e n t i o n I s s u e , T89-118.  32.  F o s t e r , B.B. 1969. L i n e a r programming: A method o f d e t e r m i n i n g l e a s t c o s t blends or mixes i n papermaking. T a p p i 52 ( 9 ) : 1958-60.  33.  F r a z i e r , W.C. 1977. V a n c o u v e r , B.C.  34.  G a v e l i n , G. 19 76. New r e f i n e r p r o c e s s f o r m a n u f a c t u r e of mechanical pulps from chips. P u l p P a p e r Mag. Can. 77 ( 1 2 ) : 91-3.  35.  G i e r t z , H.W. 1976. The i n f l u e n c e o f TMP t e m p e r a t u r e o n f i b e r and paper p r o p e r t i e s . Extended a b s t r a c t s . C a n a d i a n Wood C h e m i s t r y Symposium, Mont G a b r i e l , P.Q. 3 pp.  36.  G u g l i e l m o , R. 1975. Method o f p r o d u c i n g h i g h y i e l d pulp a t high b r i g h t n e s s f o r papermaking. Canadian P a t e n t No. 962,810. 8 pp.  37.  Guha, S.R.D. a n d S a x e n a , V.B. 1961. Writing, printing and w r a p p i n g p a p e r s f r o m G m e l i n a a r b o r e a Roxb. Res. I n d . 6 ( 8 ) : 280-1.  *Not c i t e d i n t e x t .  Technical Section. M o n t r e a l , Quebec.  Standard Testing  MacMillan Bloedel Research L t d . (Personal communication).  62. 38.  Guha, S.R.D., D h o u n d i y a l , S.N., N a t h , P., Mathew, G.M. and Sharma, Y.K. 1 9 6 7 . C h e m i c a l , s e m i c h e m i c a l a n d mechanical pulps from Eucalyptus g r a n d i s . Indian F o r e s t e r 93 ( 6 ) : 360-72.  39.  Guha, S.R.D., Sharma, Y.K., S i n g h , S.P. a n d G u p t a , R.K. 1968. S t u d i e s on t h e e f f e c t o f p u l p b l e n d i n g . I n d i a n P u l p and P a p e r , p 157-61.  *40.  Hauan, S., H o y d a h l , H.E., L o r a s , V. a n d Bohmer, E. 1975. Development o f thermomechanical p u l p . P a p i e r 29 ( 7 ) : 269-74.  41.  H o g l u n d , H., S o h l i n , U. a n d T i s t a d , G. 1 9 7 5 . The e f f e c t o f t h e p h y s i c a l p r o p e r t i e s o f t h e wood o n chip refining. TAPPI/CPPA IMPC. S a n F r a n c i s c o : 77-85. ( P r e p r i n t ) .  42.  H o g l u n d , H. a n d B o d i n , 0. 19 76. M o d i f i e d thermomechanical pulp. Svensk P a p p e r s t i d n i n g (11): 343-7.  *43.  H o g l u n d , H . , > J o h n s s o n , E. a n d T i s t a d , G. 1 9 7 6 . S h i v e s i n mechanical pulp. Part I . Effects of their thickness distribution. Svensk P a p p e r s t i d n i n g (11): 348-53.  44.  Hughes, J . F . a n d E s a n , D. 1 9 6 9 . V a r i a t i o n i n some s t r u c t u r a l f e a t u r e s and p r o p e r t i e s o f Gmelina arborea. T r o p i c a l S c i e n c e 11 ( 1 ) : 2 3 - 3 7 .  45.  I l o a b a c h i e , C.I.S. 1974. I n v e s t i g a t i o n o f t h e s t r e n g t h and r e l a t e d p r o p e r t i e s o f I d i g b o ( T e r m i n a l i a ivorensis). B.Sc. T h e s i s . U n i v e r s i t y o f Ibadan, N i g e r i a , D e p a r t m e n t o f F o r . R e s . M g t . 76 p p .  46.  J a c k s o n , M. 1 9 7 7 . M a c M i l l a n B l o e d e l R e s e a r c h L t d . , V a n c o u v e r , B.C. (Personal communication).  47.  J e n s e n , W. 19 76. Thermomechanical p u l p - a c h a l l e n g e to research. C e l l u l o s e Chemistry and Technology 10 ( 5 ) : 627-35.  48.  K e a y , R.W.J., O n o c h i e , C.F.A. a n d S t a n f i e l d , D.P. 1 9 6 4 . N i g e r i a n t r e e s , V o l . I I . Dept. o f F o r . Res. Ibadan, Nigeria. 495 p p .  * Not c i t e d i n t e x t .  63.  49.  Keays, J.L. 1975. Summary a n d a n a l y s i s o f t h e 1975 I n t e r n a t i o n a l M e c h a n i c a l P u l p i n g C o n f e r e n c e , San Francisco. ( U n p u b l i s h e d . ) 14 pp.  50.  K e a y s , J . L . a n d L e a s k , R.A. 1973. Refiner mechanical p u l p - p a s t , p r e s e n t and p o t e n t i a l . Paper Trade J o u r n a l 157 ( 3 5 ) : 20-9.  51.  K o z i c h , R.F. 1974. D i s k r e f i n e r d e s i g n and o p e r a t i n g p a r a m e t e r s . f o r t r e a t i n g hardwood p u l p s . Paper Paper I n t l . 16 ( 4 ) : 63-5.  *52.  K u r d i n , J.A. 1975. Steam r e l a t e d p r o b l e m s i n mechanical pulping. TAPPI/CPPA I n t e r n a t i o n a l M e c h a n i c a l P u l p i n g C o n f e r e n c e , San F r a n c i s c o : 123-5. (Preprint)  53.  K u r d i n , J.A. 1976. TMP c o n t r o v e r s y c r e a t i n g c o n f u s i o n . P a p e r 3 0 t h A n n u a l A p p i t a C o n f e r e n c e , Q u e e n s t o w n , New Zealand. 5 pp.  54.  K r a t z l , K. and P a s z n e r , L. 1970. The a q u e o u s h y d r o l y s i s , e t h a n o l y s i s and o x i d a t i o n o f g - a r y l e t h e r bonded l i g n i n b u i l d i n g u n i t s and t h e i r s u l f o n i c a c i d s . C e l l u l o s e Chem. T e c h n o l . 5, 293-303.  55.  K r u g e r , E., R u f f i n i , G., G r a n d i n i , G. a n d G h i s l a n d i . 1973. Method o f p r o d u c i n g h i g h y i e l d p u l p a t h i g h b r i g h t n e s s f o r papermaking. C a n a d i a n P a t e n t No. 934,107.  56.  K w e i , N.L. a n d G a r c e a u , J . J . 1975. Optimum c o m b i n a t i o n s o f g r o u n d w o o d f r a c t i o n s f o r maximum s h e e t s t r e n g t h . TAPPI/CPPA I n t e r n . Mech. P u l p i n g C o n f . , San F r a n c i s c o : 23-9. (Preprint).  57.  Lamb, A.F.A. 1968. Fast growing timber trees of the l o w l a n d t r o p i c s , No. 1 G m e l i n a a r b o r e a . Commonw e a l t h F o r e s t r y I n s t i t u t e , O x f o r d . 30 pp.  58.  L a p s i n k a , I . 1972. Worldwide u t i l i z i a t i o n o f hardwoods in the pulp industry. P r z e g l a d P a p i e r 28 ( 4 ) : i 1 2 3 - 7 .  59.  L e a s k , R.A. 1968. Chemimechanical p u l p s from T a p p i 51 ( 1 2 ) : 117-20A.  60.  L e a s k , R.A. 1975. P u l p P a p e r Mag.  * Not c i t e d  i n text.  hardwoods.  Review o f thermomechanical p u l p i n g . Can. 76 ( 1 0 : 52-60.  64. 61.  *62. 63.  *64.  M a c d o n a l d , R.G. a n d F r a n k l i n , J.N. E d . (1970 r e v . e d . ) . P u l p and P a p e r M a n u f a c t u r e . Second Ed. V o l . I . The P u l p i n g o f Wood. McGraw H i l l , New Y o r k . 769 p p . M e r e t , R.G. 1976. MacMillan Bloedel Research L t d . , Vancouver, B.C. N a m i k i , N. 1973. Manufacture of newsprint w i t h intense u t i l i z a t i o n o f h a r d w o o d and o t h e r wood r e s o u r c e s . T a p p i 56 ( 1 0 ) : 92-5. N o k o e , T.S. 19 74. S p e c i f i c g r a v i t y v a r i a t i o n i n Gmelina a r b o r e a L i n n , grown f o r p u l p w o o d i n some p a r t s o f N i g e r i a , West A f r i c a . FRST 545 S e m i n a r , U n i v e r s i t y of B r i t i s h Columbia. 17 p p .  65.  O b i a g a , R . I . and Wayman, M. 1969. K r a f t and p o l y s u l f i d e d e l i g n i f i c a t i o n o f a t r o p i c a l hardwood, Gmelina arborea. P u l p P a p e r Mag. Can. 70 ( T 2 7 0 - 8 ) .  66.  O h n i s h i , K., Awaya, S. a n d Egawa, K. 1968. r e f i n e r g r o u n d w o o d as n e w s p r i n t f u r n i s h P u l p P a p e r Mag. Can. 69 ( 1 9 ) : 79-83.  67.  O k e r e k e , 0.0. 19 62. S t u d i e s on t h e f i b e r d i m e n s i o n s o f some N i g e r i a n t i m b e r s and o t h e r raw m a t e r i a l s . Part I . Federal I n s t i t u t e of I n d u s t r i a l Research, R e p o r t No. 16. 9 pp.  68.  O r g i l l , B. 1975. E f f e c t of chemical preimpregnation on t h e r m o m e c h a n i c a l p u l p i n g o f hardwoods. TAPPI/CPPA I n t e r n . Mech. P u l p i n g C o n f . , San F r a n c i s c o : p 127-9. (Preprint).  69.  P a l m e r , E.R. 1973. G m e l i n a a r b o r e a as a p o t e n t i a l s o u r c e o f hardwood p u l p . R e p r i n t T r o p i c a l S c i e n c e , 15 ( 3 ) . 17 p p .  70.  P a l m e r , E.R. and G i b b s , J.A. 1974. Pulping characteri s t i c s o f Gmelina a r b o r e a and B u r s e r a simaruba from Belize. T r o p i c a l P r o d u c t s I n s t i t u t e , L o n d o n . 27 p p .  71.  P a n s h i n , A . J . a n d de Zeeuw, C. 1970. T e x t b o o k o f Wood Technology. T h i r d e d . V o l . I . M c G r a w - H i l l , New York. 705 pp.  72.  P e h , T.B. 1964. P u l p i n g s t u d i e s on M a l a y a n e x o t i c species. 1. G m e l i n a a r b o r e a Roxb. Res. P a m p h l e t No. 44. F o r e s t Res. I n s t . , F o r e s t D e p t . , M a l a y a . 22 pp.  * Not  cited i n text.  Hardwood component.  65. 73.  P e t e r i , R. woods.  1952. Tappi  Pulping studies with African 35 ( 4 ) : 157-60.  tropical  74.  P e t e r s o n , H.E. and N e l s o n , D.G. 1972. Production of r e f i n e r mechanical p u l p from aspen f o r p u b l i c a t i o n p r i n t i n g papers. T a p p i 55 ( 3 ) : 3 9 6 - 4 0 1 .  75.  P i e t r o , G. 1975. System to a v o i d thermal d e g r a d a t i o n o f c h e m i c a l compounds d u r i n g t h e t r e a t m e n t o f wood chips. C a n a d i a n P a t e n t No. 9 7 7 , 9 0 5 . 6 pp.  76.  Prejet, J. 19 74. New B a u e r p r o c e s s f o r m a n u f a c t u r i n g m e c h a n i c a l p u l p . A T I P Rev. 28 ( 2 ) : 1 0 5 - 2 1 .  77.  R a p s o n , W.H. Ed. 1963. M o n o g r a p h S e r i e s No. USA. 416 pp.  78.  R i c h e s , A.W. and M i t c h e l l , G.W. 1977. Experience with cottonwood (Populus t r i c h o c a r p a ) i n thermomechanical pulp furnish. Paper, J o i n t Meeting of the P a c i f i c C o a s t S e c t i o n a n d W e s t S e c t i o n o f CPPA T e c h n i c a l Section, Victoria.  79.  R y d h o l m , S.A. 1965. Pulping processes. Interscience. J o h n W i l e y a n d S o n s I n c . New Y o r k - L o n d o n - S y d n e y .  80.  S c h u t t , C. 1964. Forming t e s t sheets i n the l a b o r a t o r y . I. A Review of L i t e r a t u r e . P a p e r i j a P u u No. 4 a , p 167-92.  81.  S c h u t t , C. 1964. Forming t e s t sheets i n the l a b o r a t o r y . II. A Review o f L i t e r a t u r e . P a p e r i j a Puu 6 ( 4 ) : 315-22.  82.  S k e e t , C.W. and A l l a n , R.S. 1968. Standardization of h o t d i s i n t e g r a t i o n method f o r m e c h a n i c a l p u l p evaluation. P u l p P a p e r Mag. Can. 69 ( 4 ) : 71-3.  83.  Sosanwo, 0. 1976. S t u d i e s on G m e l i n a a r b o r e a . P a r t IV. Sulfate-oxygen cooking of N i g e r i a n Gmelina arborea wood. P a p e r i j a Puu No. 6-7, p. 4 1 9 - 2 6 .  84.  Sosanwo, 0. and L i n d b e r g , J . J . 1975. S t u d i e s on Gmelina arborea. P a r t I I . F i b e r d i m e n s i o n s and some a n a t o m i c a l a s p e c t s o f N i g e r i a n G m e l i n a a r b o r e a wood. P a p e r i j a Puu No. 7, p. 482-85.  The b l e a c h i n g o f p u l p . TAPPI 27. TAPPI, A t l a n t a , G e o r g i a ,  *85.  86. *87.  Sosanwo, 0. and L i n d b e r g , J . J . 1976. S t u d i e s on Gmelina arborea. P a r t I I I . Structural analysis o f m i l l e d wood l i g n i n f r o m t h e N i g e r i a n G m e l i n a a r b o r e a wood. P a p e r i j a P u u , S p e c i a l Number 4 a , p. 201-6. Stamm, A . J . 1964. Wood a n d C e l l u l o s e S c i e n c e . P r e s s , New Y o r k . 549 p p .  Ronald  S t y a n , G.E. 1975. C h e m i c a l f a c t o r s a f f e c t i n g groundwood brightness. P u l p P a p e r Mag. Can. 76 ( 1 2 ) : 88-90.  88.  TAPPI S t a n d a r d s and P r o v i s i o n a l Methods. A t l a n t a , G e o r g i a , USA.  1977.  89.  TAPPI. 1976. Introduction to pulping technology. Tappi Home S t u d y C o u r s e . No. 2 ( a u d i o t a p e and s t u d y guide).  *90.  V a l k a m a , E. a n d K o s t i a i n e n , A. 1973. Latest experiences of r e f i n e r mechanical pulp manufacture i n F i n l a n d . P a p e r i j a P u u 55 ( 5 ) : 373-5, 379-80, 382-4.  91.  Wahren, D. ( C o m p i l e r ) , J a c k s o n , M. (MB L t d . , V a n c o u v e r , B.C.) (Translator from o r i g i n a l Swedish). 1973. P r i n t i n g p a p e r i n f o r m a t i o n t e x t i s s u e d by Holmens B r u k AB, N o r k o p i n g , Sweden. 20 p p .  92.  Yeom, F.B.C. a n d S a n d r a s e g a r a n , K. 1966. G r o w t h and y i e l d o f Yemane ( G m e l i n a a r b o r e a R o x b . ) . Malayan F o r e s t e r 29 ( 3 ) : 1 4 0 - 5 1 .  93.  de Zeeuw, C. a n d G r a y , R.L. 1972. Specific gravity v a r i a t i o n i n G m e l i n a a r b o r e a Roxb. IAWA B u l l e t i n No. 3, 3-11. 20 p p .  * Not c i t e d  i n text.  TABLE I IMPORT OF PAPER AND PAPERBOARD FEDERAL REPUBLIC OF NIGERIA  Product  Type  1963 Kg  Newsprint 4,808,079 Printing & Writing 8,119,303 K r a f t P a p e r & B o a r d 3,011,853 C i g a r e t t e Paper 199,581 Machine-Made Paper and B o a r d 1,279,130 Fiberboard & Other B u i l d i n g Board 2,404,040 Hand-Made P a p e r 18,144 P a p e r & P a p e r b o a r d 20,865,249  $  Kg  1964 $.  Kg  1965 $  926,271 2,388,002 935,542 195,644  4,236,553 6,196,072 1,469,639 263,084  979,073 2,439,049 566,658 212,394  4,717,361 9,253,284 5,170,953 326,587  1,076,121 3,588,362 1,507,951 207,766  628,712  1,741,795  725,690  2,340,537  922,771  486,312 11,497 824,975  1,778,082 907 6,985,322  367,609 804 2,010,476  2,159,100 136,078 6,622,449  498,050 36,520 883,420  Subtotal  21,926,655  6,396,955 22,671,454  7,301,753  30,817,066  8,722,641  Packing Containers F i l l i n g Containers Envelopes, W r i t i n g Blocks, e t c . E x e r c i s e Books, Stationery, etc. A r t i c l e s o f Pulp, Paper & Board  10,886,217 444,521  4,030,720 11,430,528 220,548 562,455  4,451,821 253,392  6,059,994 417,305  3,633,504 200,794  886,071  1,170,268  781,301  Subtotal GRAND TOTAL  Source:  961,616  659,851  1,288,202  997,105  1,046,172  1,024,607  2,491,196  3,116,403  3,517,517  8,402,220  9,753,859  9,157,722  14,799,175  17,055,612  17,882,363  FAO Rome No. TA252 9 ( 8 ) .  TABLE I I FIBER CHARACTERISTICS OF GMELINA ARBOREA  Statistic  Observation  F i b e r length  (ym)  1  F i b e r width (ym)  1010 28  1  F i b e r w a l l t h i c k n e s s (ym)  3  Lumen width (ym)  22  1  Length-width Runkel  ratio  Flexibility ....  1  ratio  0.27  ratio  3  1.  1000 microns  2.  Runkel r a t i o = 2W L  4.  0.79  (ym) = 1 mm.  where W L 3.  36  2  = c e l l - w a l l thickness = Lumen diameter.  F l e x i b i l i t y r a t i o = Coefficient of f l e x i b i l i t y expressed i n p e r c e n t . „ J-J- • . . el • i_ • n • x. Width o f Lumen , C o e f f i c i e n t o f f l e x i b i l i t y = ~ • -,., * • . — x 100 Width o f f i b e r k  c  nn r  c  1  Source: FAO Rome Fo: MISC/75/31 (10).  00  TABLE I I I E F F E C T OF CHIP S P E C I F I C A T I O N I N PULPING PROCESS  Chip  Parameter  Kraft  Sulfite  Length Preferred Range, mm  Not t o o c r i t i c a l C r i t i c a l  Width  Not  Thickness Preferred Range, mm  Very  15-25  Bark  critical critical  Critical for production economy  Preferred Range, mm  Not  known  critical  Not  c r i t i c a l Not  known  Not  critical  Not  known  known  critical I Very  critical  Hard I m p u r i t i e s (sand, metal)  Critical for high y i e l d  Critical for dissolving pulp  C h i p Damage  Not  critical  Very  Moisture  Not  critical  Not  1  known  Not  1%  Content  Not  Not  (solid wood) Constancy  Content  Refiner-Mechanical  25-35  1.5-4  Chip Density  NSSC  critical critical  Constancy  critical  Critical for|Critical production economy Very c r i t i c a l  forplate  Not  c r i t i c a l Not  Not  c r i t i c a l Very  known critical  life  TABLE I V EFFECT OF CHEMICAL PRETREATMENT ON THE CHARACTERISTICS OF OPEN DISCHARGE AND PRESSURE REFINER PULPS MADE FROM SOFTWOODS  R e f i n e d by  Open  Pretreatment  Discharge P r e s s u r e R e f , 280°F 2% N a S 0 2% N a S 0 10 m i n , 250°F 10 m i n , 250°F None pH 6.5 None pH 6.5  Csf, ml  121  134  81  116  Density, g/cc  0.36  0. 37  0. 39  0.42  Tear F a c t o r  78  92  86  82  Burst  13  19.5  24  20  3180  4090  4730  3770  97.1  9 2.6  97.2  96.1  45  57.5  51. 3  54.8  58.6  64.1  59.5  58.7  55.4  59. 8  56. 3  .54.6  2  Factor  Breaking  Length, m  Opacity Brightness  2  2  -  Elrepho 1% Z n S 0  3  4  1 hr. Reversion,  105°C  Source: Personal communication (33).  3  TABLE V DEPENDENCE OF PHYSICAL PROPERTIES OF MECHANICAL PULP ON L AND S FACTORS Model:  P h y s i c a l P r o p e r t y , Y^  Stone  Y± =  a  L + S b  +  c  L i n e a r Regression E q u a t i o n : Groundwood Thermomechanical Pulp  Freeness, ml  -170.4S +  Bulk, cm /g  -0.419S + 0.0067L + 3.03 0.043L -  3  B u r s t Index, kPa.m /g 2  B r e a k i n g Length, m Tear Index, mN.m /g 2  Wet Web S t r e n g t h , g/cm  Source:  0.68S + 2173.7S + 0.063L +  40. 8S +  P e r s o n a l Communication  1.20L +  278  0.014L - 0.35 20.9L -  9.2L -  104S -  116  0.65S - 2.23  0.96S - 0.019L + 0.24  897  1270S -  0.943S + 1.03  0.14L +  1.93S -  3.6  28S -  0.40L +  45  32.8  (46) .  53L + 2874  TABLE V I RESULTS OF EVALUATION OF THE PROPERTIES OF THE GMELINA MECHANICAL PULPS  Presteamed, 10 m i n , 265 F, 24 p s i g  Pretreatment  Sample  Ident.  A3  Yield, % S p e c i f i c Energy, HPD/T Debris, % Csf, ml B a s i s W e i g h t , g/m D e n s i t y , g/cm Tear Index, mN.m /g B u r s t Index, kPa.m /g B r e a k i n g L e n g t h , km Stretch, % TEA I n d e x , mJ/g Brightness, (Elrepho), % Opacity, % Scattering Coeff., cm /g Absorption Coeff., cm /g  None A4  A5  B3  96.8  B4  B5  Presteamed, 10 m i n , 265 F, 24 p s i g , 1% NaOH 10% o n Wood C4  95.7.  C5  C6  Presteamed, 10 m i n , 265°F, 24 p s i g , 2% N a S 0 20% on Wood, pH 6.5 D4 D5 D6 2  89.6  3  95.3  64.2 1.6 205 62.0 0.25  80.1 0.4 94 62.6 0.28  87.2 0.2 46 61.4 0.29  71.5 0.9 373 60.5 0.24  92.0 0.4 89 62.4 0.29  98.1 0.3 47 61.0 0.31  98.6 0.1 235 60.8 0. 33  109.2 0.1 153 62. 5 0.35  116.0 0.0 120 61.5 0. 35  94.0 0.2 187 57.6 0.27  106.2 116.5 0.2 0.1 116 76 61.1 62.1 0.29 0.31  1.0  1.4  1.5  1.3  1.8  2.1  4.0  3.7  3.7  1.7  1.7  1.6  0.3 1.0 0.6 28.2  0.4 1.1 0.5 28.3  0.8 2.3 0.6 32. 7  1.0 2.6 0.7 45. 3  1.0 2.7 0.7 45.7  0.3 0.9 0.5 24. 3  0.4 1.2 0.5 31.6  0.5 1.4 0.6 39.9  52.5 53.9 54.5 48 .4 49.8 97.6 98.5 99.2 95.7 99.6  50.5 99.7  39.6 40 .4 97.6 99. 3  40.7 99.0  56.2 56.8 94.8 97.2  56.5 96.9  2  771  900  1089  590  776  664  763  2  73.2  78.5 92.1 67.8 131.2 130. 3 98.2 126. 8 127.2  2  3  2  2  0.2 0.3 0.7 1.1 0.5 0.6 20.9 35. 7  0.4 0.2 1.4 0.6 0.6 0.5 50.4 12. 8  1066 576  1056  773  787  47.3 58. 7  55. 0  TABLE V I I RESULTS OF BAUER McNETT C L A S S I F I C A T I O N OF THE GMELINA MECHANICAL PULPS  Sample Identification  A5  Parameter  4  (Presteamed)  14/28  Screen 28/48 48/100  100/200  P200  Weight, g  0.0066  0.1301  1.2585  2.6572  2.2257  3.7219  Length,  0.943  1.347  0.920  0.748  0.456  0.1.  mm  Weighted Length  B  R14  Fiber (WL) 0.0062238 0.1752447 1.15782  1.9875856 1.0159192 0.37219  Weight, g  0.0084  0. 1276  1.3347  2.9225  2.6075  2.9993  Length,  0.943  1. 347  0.920  0.748  0.456  0.1  1.18902  0.29993  mm  Weighted Length Weight, g  Fiber (WL) 0.0079212 0.1718772 1.227924 2.18603 0.0001  0. 0214  L e n g t h , mm 0.943 1. 347 (Caustic Pretreatment) Weighted F i b e r 0.0000943 0.028858 Length.(WL) Weight, g  0.0108  0.1789  3.3414  2.1641  2.0164  2.4566  0.920  0.748  0.456  0.1  3.074088 1.6187468 0.9194784 0.24566 3.53172  2.0802  1,7203  2.4781  D5 1.347 0.748 L e n g t h , mm 0.920 0.456 0.1 0.943 (Sulfite Weighted F i b e r Pretreatment) L e n g t h (WL) 0.0101844 0.2409783 3.249164 1.5559896 0.7844568 0.24781  TABLE V I I I L- AND S-FACTORS OF THE GMELINA MECHANICAL PULPS  Sample  A4 B4  Identification  (No P r e t r e a t m e n t ) (Presteamed)  L-Factor  S-Factor ml  13.95  705  14. 71  737  Cq  (Caustic  Pretreatment)  33.63  650  D5  (Sulfite  Pretreatment)  37.21  724  TABLE I X VALUES OF GMELINA MECHANICAL PULP PROPERTIES EXTRAPOLATED AT 9 0 m l C s f  Sample I d e n t i f i c a t i o n Pretreatment  A None  C s f , ml  90  90  90  90  81  93  120  113  0.28  0.30  0.36  0.30  T e a r I n d e x , mN.m /g  1.4  1.9  3.6  1.6  B u r s t Index,  0.33  0.35  1.1  0.47  1.2  1.0  2.8  1.3 .  0.6  0.6  0.8  0.6  TEA I n d e x , mJ/g  40  28  52  '3« 7  Brightness  54  50  41  57  98.5  99.4  99.9  97.3  Specific  Energy,  Density,  g/cm  HPD/T  3  2  kPa.m /g  Breaking Length, Stretch,  2  km  %  (Elrepho), %  Opacity, %  B Presteamed  C Caustic  D Sulfite  Scattering Coefficient,  cm /g  960  1038  854  795  Absorption Coefficient,  cm /g  80  127  142  58  2  2  TABLE X RESULTS OF EVALUATION OF GMELINA (CAUSTIC TREATED) PULP AND WEST COAST STONE GROUNDWOOD  Gmelina (Caustic Treated)  Sample I d e n t i f i c a t i o n Csf, ml  West Coast SGW  90  84  61.6  61.2  0.36  0. 37  3.6  3.4  B u r s t Index, kPa.m /g  1.1  0.8  B r e a k i n g L e n g t h , km  2.8  2.5  Stretch, %  0.8  1.4  41  52.2  99.9  97.8  B a s i s W e i g h t , g/m Density,  g/cm  Tear Index,  2  3  mN.m /g 2  2  Brightness  (Elrepho), %  Opacity, % Scattering Coefficient,  cm /g 2  854  781  Absorption  cm /g  142  76.9  Coefficient,  2  TABLE X I RESULTS OF EVALUATION OF WEST COAST AND GMELINA SEMI-BLEACHED KRAFT (SBK) PULPS  Sample I d e n t i f i c a t i o n  Gmelina  SBK  W e s t C o a s t SBK  520  684  59.0  63.2  0. 66  0.58  T e a r I n d e x , mN.m /g  10.6  23.5  B u r s t Index, kPa.m /g •  2.7  4.6.  Breaking Length,  4.2  5.7  Stretch, %  1.9  2.1  TEA I n d e x , mJ/g  590.8  835.1  Brightness  72.5  62.8  81.0  72. 9  Csf, ml Basis Weight, Density,  g/cm  g/m  2  3  2  2  km  (Elrepho), %  Opacity, % Scattering Coefficient,  cm /g 2  390  260  Absorption  cm /g  6.2  4.2  Coefficient,  2  TABLE X I I RESULTS OF EVALUATION  Sample I d e n t i f i c a t i o n Proportions  (Mech/SBK)  OF SIMULATED  NEWSPRINT HANDSHEETS  WC/SBK a n d G/SBK a n d WC/SBK a n d WC/SGW G m e l i n a Mech. G m e l i n a Mech. 85/15 80/20 75/25 80/20 75/25 70/30 75/25 70/30 60/40 195  236  254  169  209  237  180  194  233  62.1  61.4  58. 7  60.9  61.4  61.8  62.4  63.8  64 . 9  0. 37  0.38  0. 39  0.40  0.41  0.42  0.39  0.42  0.42  T e a r I n d e x , mN.m /g  7.8  9.3  10.0  7.8  9.1  9.8  4.7  5.1  6.0  B u r s t Index,  2  1.2  1.3  1.4  1.5  1.7  1.9  1.4  1.4  1.5  B r e a k i n g L e n g t h , km  2.8  3.2  3.2  3.2  3.4  3.7  3.1  3.0  3.4  Stretch,  0.7  0.9  0.9  1.9  2.0  2.1  0.9  0.9  1.0  41.7  42.1  42. 3  52.4  53.2  54.3  43.5  43.5  45.2  96.7  96.0  93.5  96.0  95.6  93.9  96.8  96.8  96.7  545  530  454  633  608  583  550  540  550  81. 0  77.5  68.2  59.6  52.9  45.6  76. 7  75. 4  69.6  Csf, ml B a s i s W e i g h t , g/m Density,  g/cm  2  3  2  kPa.m /g  %  Brightness  (Elrepho), %  Opacity, % Scattering cm /g  Coefficient,  Absorption cm /g  Coefficient,  2  2  WC/SBK  West C o a s t S e m i - B l e a c h e d  WC/SGW  West C o a s t S t o n e  G/SBK  Kraft  Groundwood  Gmelina Semi-Bleached  Kraft  TABLE  XIII  WET STRENGTH TEST RESULTS OF THE SIMULATED NEWSPRINT MIXES  Sample  Identification  Level  Low  High  Pressing  Pressing  WC/SBK a n d G/SBK a n d Gme!_ i n a Mech. G m e l i n a Mech. 85/15 80/20 75/25 75/25 70/30 60/40  Property Stress,  g/cm w i d t h  55.5  55.1  57.5  4 7. 6  51.6  54. 7  Strain,  %  4.3  6.0  6.0  5.8  6.0  6.3  Solids, %  28.6  24.1  28.4  28. 8  28.1  28.8  Stress,  g/cm w i d t h  90.2  89.8  85.8  79.9  81.9  83.9  Strain,  %  5.3  5.0  5.1  4.4  5.1  5.2  38.7  38.9  38.9  38. 7  38.6  38.9  Solids, %  WC/SBK G/SBK  West C o a s t S e m i - B l e a c h e d Gmelina Semi-Bleached  Kraft  Kraft  FIGURE 1.  Part Cross-Section  Stem o f Gmelina arborea  Roxb.  (2.4X)  CO o  81.  0 .01 1950  1954 FIGURE 2.  Source: S t a t i s t i c s  1966 Use o f R e s i d u e M a t e r i a l s f o r P u l p i n g i n B r i t i s h C o l u m b i a a n d Canada : Canada ( 2 4 ) .  FIGURE  3.  Diagramatic  Representation  of  a  Typical  Chip  oo  FIGURE 6.  P h o t o m i c r o g r a p h C a u s t i c P r e t r e a t e d P u l p Sample  (C)  (40X)  87.  RUPTURE)  I I  CHOH COOK  FIGURE 8.  Cellulose  Oxidation  S o u r c e : T h e P u l p i n g o f Wood ( 6 1 )  88.  FIGURE 9.  FIGURE 10.  P h o t o m i c r o g r a p h West C o a s t S e m i - B l e a c h e d K r a f t P u l p (26X)  Photomicrograph Gmelina Semi-Bleached K r a f t Pulp  (26 X)  89.  FIGURE 1 1 .  FIGURE 12.  P h o t o m i c r o g r a p h C r o s s - S e c t i o n West C o a s t S e m i - B l e a c h e d K r a f t P u l p (160X P h a s e C o n t r a s t )  Photomicrograph C r o s s - S e c t i o n Gmelina S e m i - B l e a c h e d K r a f t P u l p (160X P h a s e C o n t r a s t )  90.  •5i  g u \  Cn >i  -P  •H CO  O Gmelina Mech. + WC/SBK  gO.3-1  A  WC/SGW and WC/SBK  t  *  Gmelina Mech. + G/SBK  0  0  — i —  10  FIGURE 13,  — i —  20 30 SBK Content, %  To  D e n s i t y on Semi-Bleached K r a f t Content o f S i m u l a t e d Newsprint Handsheets.  12-.  Cn \  10-  g g X  8-  In  cu  u  (TJ  6-  QJ  O Gmelina Mech. + WC/SBK  EH  A WC/SGW + WC/SBK  4 0  K - i —  10  FIGURE 14  - i —  20  —r—  -r—  Gmelina Mech. + G/SBK  40 30 SBK Content, %  50  — r  60  Tear Index o f S i m u l a t e d Newsprint Handsheets.  91.  3-1  \ \ CM  e  •  In  2-  1-  © G m e l i n a Mech + WC/SBK A WC/SGW a n d WC/SBK X G m e l i n a Mech + G/SBK  +J  Bu  U  0  —I  10 FIGURE 1 5 .  1  1—-  20 30 SBK C o n t e n t ,  1  40  ~ i —  50  B u r s t Index on Semi-Bleached K r a f t Content o f Simulated Newsprint Handsheets  -P cn c CD  * 3-  Cn C •H  O G m e l i n a Mech + WC/SBK  cd  A WC/SGW a n d WC/SBK X G m e l i n a Mech + G/SBK  QJ o ffl  ot  —r—  10  FIGURE 16.  20 30 40~ SBK C o n t e n t , % B r e a k i n g L e n g t h on Semi-Bleached K r a f t Content o f Simulated Newsprint Handsheets  92.  2.0  1. 5  u  -P cu +J  00  1. OH  © G m e l i n a Mech + WC/SBK 0. 5H  i  10  FIGURE 1 7 .  To  l —  30 SBK C o n t e n t ,  4  WC/SGW a n d WC/SBK  H  G m e l i n a Mech + G/SBK  —r—  40  50  S t r e t c h on S e m i - B l e a c h e d K r a f t Content of Simulated Newsprint Handsheets  6O-1  re  Q.  rH W  50 •  tfl  0) CD C  •P  40 •  O G m e l i n a Mech + WC/SBK  cn  •H  AWC/SGW a n d WC/SBK  CQ  t  & G m e l i n a Mech + G/SBK  "To"  FIGURE 18,  i  — i —  20 30 SBK C o n t e n t , %  40  50  B r i g h t n e s s on S e m i - B l e a c h e d K r a f t Content of Simulated Newsprint Handsheets  100i 0\° >1 +J  •H  O G m e l i n a Mech + WC/SBK  £ 90-1 a, •o  it  — i —  10  FIGURE 1 9 .  i  A WC/SGW a n d WC/SBK X G m e l i n a Mech + G/SBK i  20 30 SBK C o n t e n t ,  40  50  O p a c i t y on S e m i - B l e a c h e d K r a f t C o n t e n t of S i m u l a t e d Newsprint Handsheets  -p c  600-4  CD •H  u  •H IH  ^ 500 1 o u C  O G m e l i n a Mech + WC/SBK  Q) 4 00  A  WC/SGW a n d WC/SBK  (0  ¥  G m e l i n a Mech + G/SBK  •rH  +J +J O CO  0  — i  10 FIGURE 2.0.  Cn  -i  — r —  — i —  20 30 SBK C o n t e n t , %  50  40  S c a t t e r i n g C o e f f i c i e n t on S e m i Bleached K r a f t Content o f S i m u l a t e d Newsprint Handsheets  80 -P CU •H  o m 604 0 o u  •H  G  o  •H  40i  +J ft rH O  CO  • G m e l i n a Mech + WC/SBK  ,t  AWC/SGW a n d WC/SBK i  10  FIGURE ,21.  — — i  1—  G m e l i n a Mech + G/SBK 1—  20 30 SBK C o n t e n t , \  40  A b s o r p t i o n C o e f f i c i e n t on SemiBleached K r a f t Content o f S i m u l a t e d Newsprint Handsheets :  r  50  95.  100 .,  HIGH PRESSING LOAD 90 1  Xi  80 4  -p  •H  IS g  CJ  \  in  70 1  cn cn  -p CO  LOW PRESSING LOAD  60  50 1  —t—  10  , 20  OGmelina  Mech + WC/SBK  RGmelina  Mech + G/SBK  —  30  40  50  SBK C o n t e n t , FIGURE ;22  Wet S t r e n g t h C h a r a c t e r i s t i c s ( S t r e s s ) o n Semi-Bleached K r a f t Content of Simulated Newsprint Handsheets  96.  FIGURE 23.  Wet S t r e n g t h C h a r a c t e r i s t i c s ( S t r a i n ) on S e m i - B l e a c h e d K r a f t C o n t e n t o f S i m u l a t e d Newsprint Handsheets  APPENDIX FORMULAS A P P L I E D I N THE  H o r s e Power Day P e r Ton, HPD/T Min KW O.D.  CALCULATIONS  = M i n x KW x 1.8 6 O.D., lb  = minutes of run = average K i l o Watt r e a d i n g over the r u n l b = Oven d r y w e i g h t o f p u l p r e f i n e d , i n l b .  F a c t o r 1.8 6 = M i n t o d a y s  =  m  KW  2.  , , Handsneet  l b t o Tons  _ 50 x Sample wt i n g e t s i n Sample N  o  o f  100 - % m o i s t u r e iOO  x  s h e  wt o f one s h e e t x 50 x % S a m p l e wt i n g A r e a o f sample i n m  Paper  3  2  „  16* ._ x scale °r sneers f  32, i f h e a v y p e n d u l u m 8, i f l i g h t p e n d u l u m Tear Index, mN.m /g 2  =  T e a r i n mN B a s i s Weight i n  6.  Burst Strength,= Burst i n p s i x kPa  7.  Burst Index, kPa.m /g 2  solids  = B a s i s Weight Caliper  T e a r S t r e n g t h , = 9.807 x _M m j_ ff mN p e r S h e e t  5.  2.4  g/m 2  B a s i s Weight,  D e n s i t y , g/cm  n  KW 0. 746 P.P., l b 2, 000  t o H o r s e Power  O.D.  i  60 X  J  g/m  2  6.90  = B u r s t s t r e n g t h i n kPa B a s i s w e i g h t i n g/m 2  97  reading  i s used i s used  98. 8.  Tensile Strength, kN/m Tensile N.m/g  10.  Index,  = 0 . 6 5 3 7 8 x a v e r a g e l o a d i n Kg  653.78 , , =—T-r—•—:—y—r x a v e r a g e l o a d B a s i s w e i g h t i n g/m i.n Kg  -  •.  z  3  Breaking Length, m  3  J  Tjr  66667 :—=-r—• 7—3- x a v e r a g e load B a s i s w e i g h t i n g/m . , i n Kg  -  2  :  3  J  T  11.  T e n s i l e Rupture Modulus, Pa (pascals)  6.5378 x a v e r a g e l o a d i n K g Caliper i n x Stretch i n %  12.  Stretch, %  0.0277778 x a v e r a g e d i s t a n c e  13.  T e n s i l e Energy Absorption, ( T E A ) , J/m  0.196  x  IQ  1 0  i n mm  x c o u n t s x l o a d x span span x w i d t h  2  14.  15.  TEA I n d e x , mJ/g O.D. B a s i s g/m  = 1 0 0 0 x TEA i n J/m B a s i s w t i n g/m Wt.,  2  16.  B a s i s Wt. Correction Factor  17.  Stress, g/specimen  18.  ;  2  Corrected g/specimen  = D r y wt o f s a m p l e x 3 33. 65 No. o f s t r i p s Target basis weight Calculated basis weight 49 Calculated basis weight = Average  scale reading  x  b ± a  b = slope a = intercept Stress  i n g/specimen  x b a s i s wt correction  factor  99. 19.  Strain, mm s t r a i n / g  20.  Strain,  %  21.  Opacity,  22.  Scattering Coefficient, cm /g  = S c a l e r e a d i n g x 1.32 x 0.07 cm = Strain  %  2  = |°r x 100  = O.D.  Absorption Coefficient, cm /g 2  1 b a s i s wt i n g/m (I-RQRQO)  ±  23.  x ^~  n  l-RoR»)  = S (1-R°°) 2 R°°  2  x  10 l/R^-R  00  

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