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A separation of uranium from pitchblende using an ion exchange method Seibold, Ervin Angus 1951

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A SEPARATION OF URAREUM FROM PI TCHBLEHDE USIHG A l ION EXCHANGE METHOD by ERVUT MGUS SET BOLD A THESIS SUBMITTED Iff PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS in the Department of CHEMISTRY We accept this thesis as conforming to the standard; required from candidates for the degree of MASTER OF ARTS Members df the Deparjanemt of CHEMISTRY THE UNIVERSITY OF BRITISH COLUMBIA April, 1 9 5 1 ABSTRACT Th i s paper d e a l s w i t h a new method o f s e p a r a t i n g uranium from p i t c h b l e n d e . The main f e a t u r e o f t h i s s e p a r a t i o n i s the use o f an i o n exchange r e s i n , Amberlite IRC-.50. The p u r i t y o f the uranium has been checked, c h e m i o a l l y and s p e c t r o g r a p h ! c a l l y . By t h i s method, uranium o f h i g h p u r i t y can be o b t a i n e d even i n the presence o f l a r g e q u a n t i t i e s o f i m p u r i t i e s . ACKNOWLEDGMENT I wish to express my deep appreciation to Dr. J. A l l e n Harris, whose consistent encouragement and valuable advice made t h i s work possible. TABLE OF CONTENTS Page INTRODUCTION * 1 EXPERIMENTAL METHODS AID RESULTS 4 Analysis of ore 4 Materials 4 Conditioning of r e s i n 4 Treatment of ore ............................. 4 Analysis of disodium uranate ................. 6 Table I 7 Chemical impurity tests 7 Spectrographic analysis 8 Table II 10 Table III 10 Table IV > 11 DISCUSSION i . . . . . . . . * 12 SUMMARY 1 6 BIBLIOGRAPHY i . 17 A SEPARATION OF URANIUM FROM PITCHBLENDE USIffft M 1M MQHAI&J METHOD INTRODUCTION In view of the present importance of uranium i n atomic energy production, the winning of this element from Its ores i s a very important problem. This problem i s especially important to us i n Canada because of the large deposits of pitchblende at Great Bear Lake. Less than twenty years ago uranium was of interest chiefly as the "mother" of the uranium series and i n i t s connection with radium. The roles are now reversed and radium has become of secondary importance. However, the method of separation i n use today (1,2,3,4) at Port Hope, Ontario, has not been appreciably changed so far as one can ascertain from the literature* This method was developed i n order to obtain radium as the main product, while uranium was merely considered an impure by-product, A method of separating uranium from many impurities that has received considerable attention lately i s the ether extraction of uranyl nitrate. The solubility of uranyl nitrate i n ether has been used for years for the separation of uranium -2-from many elements (.5,6). The extraction of uranyl n i t r a t e by ether could, be used as a means of obtaining uranium from pitchblende, but the method i s undesirable because many of the elements present i n pitchblende are also extracted with the uranium; For example, cerium (IY) and thorium are also extracted by ether under the same conditions as pertain to the extraction of uranium. Vanadium w i l l also be extracted i f the amount present i s greater than 1^. The presence of chloride ion w i l l cause the extraction of many other elements such as i r o n ( I I I ) , etc. Large amounts of sulphate ion i n t e r f e r e , and phosphate ion has been found to decrease the d i s t r i b u t i o n c o e f f i c i e n t of uranium i n an ether extraction. Apparently, once the uranium i s precipitated as the phosphate no more uranium w i l l be extracted by the ether, and even 1 2?& n i t r i c acid w i l l not redissolve uranyl phosphate. ThiB paper w i l l describe a new short method of obtaining uranium from pitchblende; This method, which uses an ion exchange re s i n , gives uranium of high p u r i t y by the use of cheap common chemicals. The f i r s t few steps i n the treatment of the ore are e s s e n t i a l l y the same as those used at the Port Hope refinery, i . e ; , roasting, solution i n sulphuric acid, and p r e c i p i t a t i o n with sodium carbonate. The next step, which might be considered as a spe c i a l type of a c i d i f i c a t i o n , i s accomplished by treating the f i l t r a t e with Amberlite IRC-jJO, a weak acid i on exchange r e s i n . This r e s i n e f f e c t i v e l y breaks the uranyl carbonate complex and absorbs a l l the uranium from -3-the solution, while a l l the other anions present are not absorbed. The uranium i s removed from the resin with sulphuric acid and precipitated with sodium hydroxide as disodium uranate of exceptionally high purity* Experiments were carried out to determine: (a) the amount of uranium recovered from the ore; (b) the amount of uranium recovered from the ore i n the presence of large amounts of impurities such as vanadium^ zirconium, thorium, beryllium and gold, as these elements were considered to be the most l i k e l y to cause contamination of the f ina l precipitate; (c) the purity of the uranium recovered i n these cases. - 4 -EXPERIMENTAL METHODS AHD RESULTS Analysis of ore: A general analysis of the pitchblende samples available was carried out according to the procedures as outlined i n Dr. J. A l l e n H a r r i s ' "Advanced Qualitative Analysis" course* The elements found were as follows; A l , As, Sb, Ba, Be, £ 1 , Ca, £u., Co, le., Au, Pb, Mg, Mja, Mo, Ni, K, P0 4, §X, Ag, Ka, Th, Sn, U, V, Zn, Zr;\ and others such as rare earths i n small quantities. The elements underlined were present i n the highest concentrations. Materials: The ion exchange r e s i n used was obtained from the Rohm & Hass Company, Philadelphia, Pa; Amberlite IRC-50, a oarboxylic acid exchanger, was used; A pitchblende ore sample C - S - 1 - 1 1 , 4 7 . 1 9 ^ U 3°8 w a s o l 3 ' t a i n e ( i from the Department of Mines and Resources. Conditioning of r e s i n : 50-60 ml. batches of r e s i n were converted to the acid form by heating them on the steam bath with 200 ml, portions of sulphuric acid solution. The r e s i n was washed with d i s t i l l e d water u n t i l free of a l l ac i d . Treatment of ore: Approximately 1 . 2 of ore was accurately weighed out and digested with 30 ml. of 1 * 1 sulphuric acid i n a 500 ml. erlenmeyer f l a s k . The ore was d i g e s t e d u n t i l d i s s o l v e d , about 30 minutes. Approximately 0.0£ g. o f barium c h l o r i d e was added to the ore a t the s t a r t o f the d i g e s t i o n . The excess h y d r o c h l o r i c a c i d formed was removed d u r i n g the d i g e s t i o n . A f t e r the ore was i n s o l u t i o n , the mixture was c o o l e d and 20-30 ml, o f water were added. Then 0.1 g. o f sodium s u l p h i t e was added with h e a t i n g to p r e c i p i t a t e any g o l d i n s o l u t i o n , 5 g, o f sodium n i t r a t e were then added with h e a t i n g to o x i d i z e the uranium, e t c . The excess n i t r i c a c i d formed was removed by e v a p o r a t i n g to fumes o f s u l p h u r i c a c i d . A f t e r c o o l i n g , the s o l u t i o n was d i l u t e d to J>0 ml, and f i l t e r e d through a medium p o r o s i t y s i n t e r e d g l a s s f i l t e r f u n n e l i n t o a 300 ml, s u c t i o n f l a s k . The r e s i d u e was w e l l washed with d i l u t e s u l p h u r f c a c i d and the washings were added to the f i l t r a t e . The r e s u l t i n g s o l u t i o n was t r e a t e d with sodium carbonate to an approximate pH o f 8, During the a d d i t i o n o f the sodium carbonate, the s o l u t i o n was kept a t room temperature by p l a c i n g the f l a s k under c o l d water. The mixture was a llowed to stand u n t i l the p r e c i p i t a t e had coagulated and was then f i l t e r e d through a medium p o r o s i t y s i n t e r e d g l a s s f i l t e r f u n n e l . The p r e c i p i t a t e was well\ walshed with a d i l u t e s o l u t i o n o f sodium carbonate and the washings were added to the f i l t r a t e . The f i l t r a t e was caught i n a 300 ml, s u c t i o n f l a s k c o n t a i n i n g 50-60 ml, o f the low exchange r e s i n . The r e s i n was i n the a c i d form. The f i l t r a t e and r e s i n were kept under a reduced pressure o f approximately 30 i n c h e s o f mercury u n t i l carbon d i o x i d e ceased - 6 -to be evolved, about 3 0 minutes. At t h i s p o i n t , the s o l u t i o n w i l l be c o l o u r e d a deep y e l l o w i f much vanadium i s p r e s e n t . A f t e r carbon d i o x i d e ceased to be evolved, the r e s i n was f i l t e r e d i n t o a coarse p o r o s i t y s i n t e r e d g l a s s f i l t e r f u n n e l and was w e l l washed with a 1?6 ammonium n i t r a t e s o l u t i o n * The washed r e s i n was then t r e a t e d with 2 0 0 ml, o f 1 0 ^ s u l p h u r i c a c i d i n a 6 0 0 ml. beaker and heated f o r 1 0 minutes on a steam bath. The r e s i n was f i l t e r e d a g a i n i n t o a coarse p o r o s i t y s i n t e r e d g l a s s f i l t e r f u n n e l and washed with d i l u t e s u l p h u r i c a c i d . The washings were added to the f i l t r a t e . The f i l t r a t e was made b a s i c by the a d d i t i o n o f excess sodium hydroxide and brought to a b o i l . A f t e r the p r e c i p i t a t e o f disodium urahate coagulated, i t was f i l t e r e d on a medium p o r o s i t y s i n t e r e d g l a s s f i l t e r f u n n e l and washed with water. The above procedure was repeated with the f o l l o w i n g contaminants added to the ore: ( 1 ) Ammonium vanadate; ( 2 ) zirconium n i t r a t e ; ( 3 ) Thorium n i t r a t e , b e r y l l i u m carbonate, and g o l d c h l o r i d e , AwBlvfll a o f disodium uranate: The p r e c i p i t a t e was anal y s e d f o r uranium by d i s s o l v i n g i t i n 4 M h y d r o c h l o r i c a c i d , r e d u c i n g the uranium i n a s i l v e r r e d u c t o r and t i t r a t i n g the reduced uranium with c e r i c ammonium sulphate a c c o r d i n g to the method o f Birnbaum and Edmonds ( 7 ) i The s i l v e r r e d u c t o r was prepared a c c o r d i n g to W i l l a r d and D i e h l ( 8 ) . TABLE I RESULTS OF ANALYSIS USING SAMPLE C - S - 1 - 1 1 , 4 7 - 1 9 ^ U3O8. Sample Weight o f Impurity Weight o f Percentage U,0o number sample added lmpuri t y found ^ 1 1 . 2 0 0 4 g. 45 . 109& 2 1 .200 2 Si 4 5 . 1 0 9 6 3 1.1998 g- 4 5 . 1 5 9 6 4 1 . 2009 fiT- NH 4V0 3 0.500 g. 4 4 . 8 0 9 6 5 1 .2016 S i NH4VO3 0.500 g. 44.8096 6 1 .200 2 g. ZrO(N0 3 ) 2 0.200 g. 44.7096 7 1 .201 5 g- ZrO(N0 3 ) 2 0.200 g. 44.7696 8 1 .1998 g. Th(N0 3 ) 4 0.100 g. 4 4 . 0 0 9 6 a BeCOj 0.100 g. AUCI3 0 . 0 5 0 g. 9 1 .2003 fit- Th(N0 3 ) 4 0.100 g. 43.90?6 a BeCO^ 0.100 g* AUCI3 0 . 0 5 0 s* ,—Low r e s u l t s are due to mechanical l o s s o f uranium. Chemioal i m p u r i t y t e s t s ; A d d i t i o n a l samples to those I n t a b l e I were c a r r i e d through by the same procedure and the f o l l o w i n g t e s t s were a p p l i e d to them: ( 1 ) The presence o f vanadium i n the disodium uranate was checked by the i r o n ( I I ) dimethylglyoxime t e s t (9) -8-(2) The presence o f zir c o n i u m i n the disodium uranate was checked by the s e n s i t i v e t e s t with b e t a - n i t r o s o -a l p h a -napthol (9). (3) The presence o f thorium i n the disodium uranate was checked by adding o x a l i c a c i d to a s o l u t i o n o f the disodium uranate i n s u l p h u r i c a c i d t h a t had been made n e u t r a l by the a d d i t i o n o f sodium hydroxide, (4) The presence o f b e r y l l i u m i n the disodium uranate was checked by adding ammonia u n t i l a s o l u t i o n 6f the disodium uranate i n s u l p h u r i c a c i d was b a s i c , ( 3 ) The presence o f g o l d i n the disodium uranate was checked by adding o x a l i c a c i d to a s o l u t i o n o f the disodium uranate i n s u l p h u r i c a c i d t h a t had been made n e u t r a l by the a d d i t i o n o f sodium hydroxide, fipqotrogr&Tihtc analysis; A d d i t i o n a l samples to those i n t a b l e I were c a r r i e d through by the same procedure and they were ana l y s e d s p e c t r o g r a p h ! o a l l y . The spectrograph!c a n a l y s i s was c a r r i e d out u s i n g a H i l g e r model E medium q u a r t z spectrograph, s i z e E 498, s e r i a l number E Spectrograph!eally s t a n d a r d i z e d copper rods from Johnson, Matthey & Co,, L i m i t e d , London, England, were used f o r the a r c source^ The s p e c i f i c a t i o n s f o r the copper rods were; l a b o r a t o r y number 2033 - 3 mm. diameter; catalogue number JM. 30; i m p u r i t i e s Ag, H i , Pb, Pe, Mn, Mg, and Ca, -9-The samples f o r a n a l y s i s were p l a c e d i n a small d r i l l e d r e c e s s i n the lower, p o s i t i v e e l e c t r o d e . The a r c was focused on the s l i t with an a u x i l i a r y q u a r t z l e n s . A l l t e s t s were conducted u s i n g the f o l l o w i n g standard c o n d i t i o n s ; (a) a DC are source c a r r y i n g a l o a d o f 4 amperes, with a 3 mm. spark gap, (o (c (d (e ( f (g (h ( i a 0.0 2 mm. s l i t width, a p r e - a r c i n g p e r i o d o f 15 seconds, exposure time 6 seconds, Eastman p l a t e s type 103a-0, Eastman D-19 developer 4 minutes, a c e t i c a c i d s h o r t stop 15 seconds, Eastman a c i d f i x 20 minutes, wash 60 minutes. A spectrogram o f each disodium uranate sample was taken, and, i n o r d e r to h e l p i n the i d e n t i f i c a t i o n o f the s p e e t r a l l i n e s o f the i m p u r i t y t h a t had "been added to the ore sample, a spectrogram o f the i m p u r i t y was a l s o taken. These spectrograms were p l a c e d s i d e hy s i d e as i n p l a t e s I , I I , e t c . I d e n t i f i c a t i o n o f the s p e c t r a l l i n e s was c a r r i e d out "by r e f e r e n c e to B r o d e t l d ) and Hodgman (11). The s p e c t r a l r e g i o n covered was from 2100 A 0 to 5000 A 0, hut p l a t e s are o n l y shown o f t h a t r e g i o n o f the spectrum t h a t c o n t a i n s the p e r s i s t e n t l i n e s o f the elements i n question,, TABLE II QUALITATIVE ANALYSIS SAMPLES' Sample Weight of Impuri ty Weight of ' 'Type of number sample added impurity analysis taken 10 = 1 .2010 g. 1H 4V0 3 0.500 g. spectrograph!c 11 1 .2004 g. NH 4V0 3 0.500 g. chemical 1 2 1 .20 24 g» 2r o ( N 0 3 ) 2 0.200 g. spectrographic 13 1 .1997 g. Zr0(N0^) 2 0.200 g. chemical 14 1 .20 0 3 g. Th(N0 3) 4 0.100 g. spectrographic BeCO^ 0.100 g. AuCl^ 0.050 g* 13 1 .2011 g. Th(H0 3) 4 0.100 g. chemi c a l BeCO^ 0.100 g. AuCl^ 0.050 g* TABLE III CO-ORDINATION OF PLATES AND SAMPLES Plate number Exposure number Spectrogram material I & II 1 NH4V03 2 Na2U20»7 from sample 10 III & IV 1 Zr0(N0 3) 2 2 Na2U207 from sample 12 V, VI & VII 1 Th(N0 3) 4 2 l a 2U20*7 from sample 14 -11 -TABLE IV RESULTS OF SPECTROGRAPHIC AND CHEMICAL ANALYSIS Sample Plate Spectrograph!e Chemical number number test test 10 I,II vanadium traces 11 vanadium absent 12 III,IV zirconium absent 13 zirconium traces 14 V,VI,VII thorium, beryllium & gold absent 15 thorium, beryllium & gold absent Additional impurities found i n the disodium uranate samples by spectrograph!c analysis were Si and B. u u TT U U U U u u u u u u u u 2977.3 2°56.1 ->°55.6 2943.9 2941 .9 2930.8 2927.4 2925.6 2924.6 2921 .7 2914.6j 2914. 2914.0 2860.5 28 58.9 u 2813.0 U 2811.3 u 2810.0 u 2807.1 Cu 2766.4 TT 2755.1 2754 .2 2739 .4 2730 .3 2725 .9 Cu 2715.5 Cu 2713.5 u 2707.0 Cu 2703.2 Cu 2701.0 u 2698.1 U 2695.5 u 2691.0 Cu 2689.3 u 2683.3 u 2672.7 u 2652.8 u 2651.8 U 2649.1 mi'A rk 2977.5 v 2962.8 v 2961.2 Cu 2957.5 v 2955.6 2952.1 2950.3 2948.1 2944.6 2942.4 V 2941.5 v 2941.4 2934.4 2930.8 2924.6 2924.0 2923.6 2920.4 2920.0 2914.9 '2860.0 2857.9 2810.3 2753.4 2739.7 2731.3 2728.6 2715.7 2714.2 V 2713.0 V 2711 .7 2707.9 2706.7 2706.2 2702.2 2700.9 2698.7 2698 .4 2697.7 2690.8 2§Q0. 2 2689.9 2688.7 688.0 2683.1 2682.9 V 2679.3 V 2678.6 I2677.8 £672.0 2661 .4 651 .9 649.4 '647.7 V V V V V V V V V V V V V V V V V V V V V V V V 7 V V 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 PLATE I 2 P" 0 =( » > > > > 0 > > O t > > > > t > > l > > 0 > > > > | > | > > t > | > u > C V J Q O ""N * > O N O l A c o v O O ° J vf- I*TNC\J rOvOJvO r<A O N O ^ ^ O O O C O ^ f ^ N O co, O O N O O OO C O CM o O - C^. 03 c o vo N O v O LT\ LT\ LT\ LT\ N ^ r ^ \ sX) o * T O N K N . N O i f r CM O C O O C ^ C ~ N O O N N A ^- C\J \£> N O C O ° J C O CVJ O Lf\ f r \ * 3 - O N « - C M L ! M A , = | - ' « l - N N ^ l - 0 » - C ~ r r \ r - O C O C—vO *fr l * \ M> CVJ 0 0 0 3 C 0 w < - ^ - O 0 N O ^ O . C O O . O C N D L r s i r \ L T \ L f \ ^ ^ J - ' * T t ' * r < M ^ r - r - T - r - T - ^ - ^ - o O O O c c o o o o o o o o o o o o o U 3555.3 u 3493.3 U 3443.0 3594.0 Cu 3576.9 Zr 3572.5 zrv 3556 .6 Zr 3545.0 Cm 3498 . 1 C U 3496 .2 Zrp 3440 .5 Cu 3438 .2 Zrp 3396.3 Cu 3395,5 Cu -3392.0 ZrP PLATE I I I U 4689.1 U 3 8 3 2 . 6 , U 3 8 3 7 . 3 -U 3831.5-Cti 38?5.0-4687.0 Zrp -4674.8 Cu 3836.8 Zr 3836.0 Zr 38 25.0 Cu PLATE IV u u TJ U u u u u u u 2894.5 2889.6 2887.3 2886.4 2871.0 28 26.2 28 21 .1 2818.0 2795.2 2793.9 u 2691.0 U 2684.0 U 2683.3 U 2597.7 2917.4 Th 28 9 9 . 7 Th 2895.1 Th 28 8 7 . 8 Th 2885.0 Th 28 8 4 . 3 Th 2883.0 Cu 2870.4 Th 28 4 2.8 Th 28 26.9 Th 28 24.4 Cu 2819.3 Th 280 2.7 Cu 2794.3 Th 2771 . 5 Th 2770.8 Th 2766.4 Cu 27.29.3 Th 2718.8 Cu 2716.3 Th 2708. 2 Th •2704.0 Th 2692.4 Th 2689.3 Cu 2687.1 Th 2684.3 Th 2658.7 Th 2598.8 Cu 2597.1 Th 2589.1 Th PLATE V U 3540.4 C u 3365.3 Cu 3307. U 3305.9 U 3300.7 U 3179.8 u 3033.2 3727.9 Th 3726.7 Th 3339.3 Th 3538.8 Thp 3537.2 Th 3469.9 Th 3392.0 Th 3367.8 Th 3358.6 Th 3351 . 2 Th 3349.3 Cu 3325.1 Th 3324.8 Th 3304.2 Th 3194 3188 3184 3180 3179 3156 3154 3154 31 26 31 24 iff 3O88 .1 Cu . 2 Th .9 Th . 2 Th .0 Th .6 Cu .7 Th . 3 Th .1 Cu .4 Th .Q Th .6 Th .1 Cu 3036.0 Cu 3034.1 Th PLATE VI 5105.5 Cu 5049.8 Th •5016.6 Cu 4919.8 Th u 4393.6 4391.1 Th 4381.9 Th 4378.2 Cu Cu U U u 4104. 2^  4096.4| 4095.71 4090.1 U U U 3932.0, 3931 .51 3931.0 u u 3831. 3829.! W94.8 Th 14086.5 Th "4085.0 Th •4080.6 Cu 40 22.7 Cu • 4019.1 ThP •3929.7 Th -3925.3 Cu -38 29.4 Th -38 25.0 Cu •3752.6 Th PLATE VII -1 2-DlgCUgglQP The procedure developed may he i l l u s t r a t e d by means of a f l o w diagram; Residue Residue F i l t r a t e P i t c h b l e n d e c o n c e n t r a t e A i r r o a s t I S a l t r o a s t 4-S u l p h u r i c a c i d l e a c h — F i l t r a t i o n 4--F i l t r a t e -h ' Sodium carbonate F i l t r a t i o n F i l t r a t e -h Amberlite IRC-j?0 r F i l t r a t i o n i Residue o f Amberlite IRC-£0 S u l p h u r i c a c i d Regenerated Amberlite IRC-j?0< F i l t r a t i o n 4--F i l t r a t e + Sodium hydroxide F i l t r a t e — F i l t r a t i o n Disodium uranate I n view of the f a c t t h a t there are a g r e a t many elements i n p i t c h b l e n d e , i t was thought necessary, when - 1 3 -devising a separation scheme, to consider the properties and reactions of most of the elements i n the periodic table i n order to determine what impurities were l i k e l y to be found i n the f i n a l p r e c i p i t a t e of disodium uranate. In t h i s consideration only those valence states of the elements were considered which were thought to be present a f t e r solution of the ore was accomplished. Some of the elements w i l l be preci p i t a t e d during the sulphuric acid leach. The most important of these elements i n th e i r p r e c i p i t a t e d form are; s i l v e r chloride, m e t a l l i c gold, lead, barium and radium sulphates, and s i l i c a . Sodium carbonate as a precipitant removes most of the remaining cations, leaving uranium i n solution as a uranyl carbonate complex. The most important elements soluble i n the sodium carbonate are; uranium, beryllium, zirconlum(hafnium), thorium and vanadium. The complex anion formed between carbonate and uranyl ions was found to be decomposed by Amberlite IRC-50 even at room temperature, with the complete absorption of uranyl ions from the solution. This may be i l l u s t r a t e d by the following equations: Ha 4|U02(00^)3] •+ H2-R > U0 2-R + H 20 + C 0 2 + 2 N a 2 C 0 } fla2C03 H- H2-R > Na2-R + H20 + CO2 Low pressure favours both these reactipns. / - 1 4 -Zireonium( hafnium) and thorium form, complex anions with the sulphate i o n s present from the a c i d l e a c h , but these complex anions are not decomposed by the i o n exchange r e s i n a t room temperature, as i s the u r a n y l carbonate complex a n i o n . Thereby g i v i n g a complete s e p a r a t i o n o f uranium from these elements* Although the case o f vanadium appears to be s t r a i g h t f o r w a r d * i . e . , i t should a c t as a normal a n i o n and not be absorbed by the i o n exchange r e s i n , i t i s complicated by the f a c t t h a t vanadium a l s o a c t s as a c a t i o n . The f o l l o w i n g e q u i l i b r i u m can be s e t up between vanadate i o n s and Am b e r l i t e I R C - 5 0 : VQVj" + H - R V 0 2 - R 4- O H _ At room temperature the r e a c t i o n i s predominately to the l e f t , o while at 1 0 0 C . the r e a c t i o n goes completely to the r i g h t . The use o f ammonium n i t r a t e as a wash s o l u t i o n , however, w i l l remove the sm a l l amount o f vanadium t h a t i s absorbed a t room temperature without removing any o f the uranium. Therefore , vanadium can be separated from uranium i f the r e a c t i o n i s c a r r i e d out a t room temperature and ammonium n i t r a t e i s used as a wash l i q u i d . A l l the normal s t a b l e anions, such as sulphate and phosphate, are not absorbed by the i o n exchange r e s i n * therefore, they are a l s o separated from the uranium, A few elements are v e r y s l i g h t l y s o l u b l e i n sodium - 1 5 -carbonate, such as copper and t i n ( I V ) . However, these elements t h a t are s l i g h t l y s o l u b l e i n sodium carbonate are a l s o s o l u b l e i n sodium hydroxide and are not p r e c i p i t a t e d w i t h the uranium. Those elements that are s o l u b l e i n sodium carbonate and sodium hydroxide such as b e r y l l i u m , g a l l i u m , t h a l l i u m ( I ) , indium and the a l k a l i e s do not i n t e r f e r e w i t h the s e p a r a t i o n . The i o n exchange r e s i n Amberlite IRC-50 was chosen f o r the f o l l o w i n g reasons: (a) I t has the h i g h e s t c a p a c i t y o f any o f the i o n exchange r e s i n s a v a i l a b l e . (b) I t i s v e r y e a s i l y and completely regenerated with d i l u t e a c i d s because i t i s a weak a c i d , (e) I t w i l l not s p l i t n e u t r a l s a l t s , such as sodium su l p h a t e , consequently more o f the r e s i n i s a v a i l a b l e f o r a b s o r p t i o n o f uranium, (d) Because o f i t s great a f f i n i t y f o r hydrogen i o n s , i t was found to be the most f a v o u r a b l e r e s i n to use f o r the s e p a r a t i o n o f uranium from thorium, z i r c o n i u m and vanadium. The s e p a r a t i o n scheme as o u t l i n e d was developed so t h a t a h i g h y i e l d o f uranium o f good q u a l i t y c o u l d be o b t a i n e d from p i t c h b l e n d e , i n a simple and economical manner. The r e s u l t s show t h i s has been ac h i e v e d . SUMMARY ( 1 ) A s a t i s f a c t o r y method o f s e p a r a t i n g uranium from p i t c h b l e n d e has been developed. The method i s s h o r t and o n l y i n v o l v e s the use o f cheap common chemical s . (2) The method c o u l d be e a s i l y adapted to l a r g e s c a l e procedures. (3) The percentage r e c o v e r y o f uranium from the standard ore sample a v a i l a b l e was over 95fi. (4) The s e p a r a t i o n can be c a r r i e d out i n the presence o f l a r g e amounts o f i m p u r i t i e s , and e s p e c i a l l y such i m p u r i t i e s as vanadium, thorium, zirconium, b e r y l l i u m and g o l d . (3) The p u r i t y o f the uranium recovered i s e x c e p t i o n a l l y good, even when l a r g e amounts o f i m p u r i t i e s are p r e s e n t . BIBLIOGRAPHY (1) R. N. Shreve, The Chemical ProcesB Industries, McGraw-H i l l Book Co. (2) A. Kuebal, J* Chem. Ed., 21, 148(1944). (3) E. V i o l , J. Chem. Ed., 3, 737(1926). (4) B. S. Hopkins, Chapters In the Chemistry of the Less Familiar Elements, Vol. I & I I , Stipes Pub. Co. (3) W. F. Hillebrand, U. S. Geol. Survey B u l l . , 78, (18 91 ) -(6) C. A. P i e r l e , J. Ind. Eng. Chem., 1 2, 60(1 920). (7) N. Birnbaum and S. M. Edmonds, Ind. Eng. Chem., Anal. Ed., 12, 155(1940). (8) H. H. Willard and H. Diehl, Advanced Quantitative Analysis, D. Van Nostrand Co, (9) F. F e i g l , Qualitative Analysis by Spot Tests, E l s e v i e r Pub. Co. (10) w . R. Brode, Chemical Spectroscopy, John Wiley & Sons* (11) M. S. Hodgman, Handbook of Chemistry and Physics, Chemical Rubber Pub, Co, 

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