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Separation of aluminium and beryllium using amyl alcohols Grassie, Vernon Robert 1942

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G 7 U z SEPARATION OF ALUMINIUM AND BERYLLIUM USING AMIL ALCOHOLS Thesis submitted by: ¥eraon Ri Grassie in partial fulfilment of the requirements for the degree Master of Arts THE UNIVERSITY OF.. BRITISH COLUMBIA March 1942 Jbrewor&r The research was carried-..out under the expert direction of Br. J, Allen Harris. lernon R«, Grassie Contentst Introduction - - — • - - - . - 1 -Methods of Analysis — • 3 (a) Hydrolysis Method . • - - 3 (b) 8-hydroxy quinoline; method 6 (c) Tannin Method- for Beryllium -•- _ 7 (d) Analysis of Iron and Chromium - - - ,7 Solubility Determinations. - - ~ . . 8 (a) Beryllium Nitrate;— - — — , = _ 8 (b) Aluminium Nitrate' - • . 13 (c) Zinc Nitrate . 17 (d) Ifegnesium t i t r a t e - . — - - - 19 (e) Iron Nitrate - . — 20 (f ) Chromium Nitrate - _ - . _ _ „ 21 Investigations for Colloidal Propertiesv- — • - 21 Conclusions - —>- •—. <—. - — - ~ ~ 22 Suggestions for Further Investigation - - ^  _ 24 References -- -- . _ _ _ 25 — 0 O 0 — (1) The use of amyl alcohol i n the separation of aluminium and l beryllium is described by Browning and Kuzurianf the separation depending upon differences in solubility of the nitrates i n this solvent. It i s stated that aluminium nitrate i s completely insoluble in amy! alcohol while beryllium nitrate is soluble to the extent of 0.02 to 0.045 grams of BeO per ml. The actual method of treatment involves evaporating of the aqueous solutions of the nitrates to a few drops and adding 10-20 ml. of amyl alcoholi The whole i s then brought to the boiling point {128-150° C) and according to the article, complete dehydration- is indicated when the fumes burn quietly at the mouth of the test-tube. Upon cooling and filtering- the beryllium-nitrate is contained in the f i l t r a t e , the aluminium'nitrate being;retained: by;the- filter'. Browning and Kuzurian determined Be.in the f i l t r a t e by extraction with water in a separating funnel, (two treatments with four times the volume of water having been: found satisfactory) and-the beryllium content then estimated by precipitation with NH^ OHj f i l t e r i n g , and igniting to BeO. It i s "noted- that "when Be: and Al are"' present'together^ small varying amounts of Be are retained by the Al even-after two treatments. The method is at least recommended by the investigators for the preparation of beryllium free from aluminium. In this investigation, solubilities of beryllium and: aluminium nitrates were checked in the four amyl. alcohols (normal, iso, secondary, and tertiary) and i n addition, solubilities! of nitrates of several related elements were determined.•In each casey no attempt was made to estimate solubilities at.other than: room temperatures. However i t was (2) observed that the solubility of aluminium nitrate remained extremely low i f s olutions were filtered while hot; Instead of evaporating aqueous solutions of the nitratesy portions of the solid nitrates were usedt less reagent being:necessary for the dehydration; In actual practice this.wouldn't be possible, but i t was noted that results obtained by. this procedure checked with; results obtained by evaporating solutions. Evaporation of the solvent was carried out in 50 ml. erlenmeyer flasks, and i n most.cases evaporation of one-half of the solution.was considered sufficient to ensure dehydration. It was observed during the investigation that' normal and iso amyl alcohols were the only isomers suitable for this workj the secondary and tertiary compounds having boiling points too low (11£CG and 102° C respectively) to guarantee-complete dehydration of the nitrates. In addition, although the nitrate of beryllium seemed quite soluble in tertiary amyl (perhaps because of incomplete, dehydration) i t was found to have very limited solubility irr secondary amyl. Soy in the subsequent investigations for the solubility of the other nitrates, only normal and iso amyl. alcohols were considered, and since they proved to be very similar i n their solvent properties, only the iso compound was actually employed. . > As previously mentioned, Browning and Kuzurian observed that some of the beryllium nitrate was retained by the aluminium. This phase of the investigation was accepted without checking, but disregarded since treatment three or four times with the solvent would probably be sufficient to remove a l l but;the last traces of beryllium. However the solubility of aluminium nitrate in the presence of beryllium was determined and found to be considerably higher;than for pure aluminium (s) nitrate. The aluminium nitrate -is colloidal i n this case and f i l t r a t i o n through.a thick asbestos f i l t e r seems sufficient to retain most of the colloidal nitrate. Methods of.Analysis; Since a very.large number of determinations were to be madej and since the solubilities: to be determined vrere not to be necessarily absolute, the. most:rapid'and least specific:method:was: sought, even with the sacrifice of a certain degree of -accuracy. (a) The.method f i r s t considered.was that of Ivanov, in which easily hydrolyzed salts (such as nitrates) of A l , Be, Zn, Fe, etc. are-determined by hydrolysis i n the presence of sodium.thiosulphate, potassium iodide, and potassium iodate. HNOg from the hydrolysis of the nitrates releases iodine from the KI and KlOg which in turn reacts with an excess of thiosulphate•* The excess thiosulphate i s then; found-by titration with standard iodine solution* The method, of coursej depends upon amount of hydrogen ion formed as the hydrolysis proceeds, and presence of either hydrogen or hydroxyl ions such as may arise from impurities in the reagents used, w i l l lead to inaccurate results. That i s to say, the actual salt being determined must be 100$ pure-. This represented no disadvantage i n i t s e l f as fas as this investigation was concerned, because compounds being used were i n the pure-state. In the case of Al and Be, the combined reactions are as followss 2A1(N0S)3+KIOg+SKI^SHgOtSNagSgOg — - > Alg(0H)gV 6KNQg,-«- 3NagS4Q6* 6KaI 3Be(l0 5)g + KIO3 + 5KI <-3HgO + 6NagS20g — — — — $ » 3Be (0H)2 4- 6KN05 SBtegS^ + 6NaI (4) The procedure i s not recommended for amounts exceeding 0.05 grams of BeO or AlgO g. To 200 ml of solution, 10 ml of 5% KlOg and 10 ml of 1% KI are added and then a known excess of: tenth-nornial NagSgOg. The whole i s then boiled for not more than 5 minutes, the flask being covered o with a watch-glassj cooled to.below 20 C, and titrated with tenth-normal iodine> using:starch-indicator* From the equations i t i s calculated that 1 ml tenth-normal sodium thiosulphate i s equivalent toj.0.001704; gm. AlgQg or to 0.001255 gm. BeO. To check the accuracy of this method, standard solutions of aluminium and beryllium nitrates were prepared-and calibrated using the oxine method: and-tannin methods respectively (these methods w i l l be discussed later) and various amounts taken for analysis. The following 1results were obtained; • Table: 1. Beryllium- -Bee added Thio.used-H/10. BeO found Diff. gm. 0.0032 2.58 0.0032 0.0000 0.0065: • 5i2i : . 0.0065 0.0000 3» 0.0097 7*68v 0.0096 -0.0001 4. 0.0130 10.39 0.0130. 0.0000 5. 0.0162 12 a 90 0.0162 0.0000 6. 0.0324 25.59 0.0321, -0.0003 7. 0.0487 38; 97 0.0489 * 0.0002 8. 0.0649 . 50.96 0.0639 -0.0010 (5) Aluminium AlgOg added Thio used N/10 AlgOg found Diff. gm. 1. 0.0021 1.49 0.0025 0.0004 8. 0.0042 2.84- 0.0048 -+- 0.0006 3. 0.0065 4.36 0.0074 + 0.0009 4 8 0.0087 5.41 0.G092- + 0.0005 5. 0.0109 7 « 55.. 0.0125 0.0016 6 a 0.0218 14.37 0.0245 + 0.0027 7. 0.0527 20.60 0.035L- +. 0.0024 8. • 0.0456 ©38' 0.0467 +• 0.0031 9. 0.0545 34.71 0.0591 + 0.0046 10. 0.0654 41.45 0.0706 + 0.0052 The method thus proved t© be very accurate i n the case of beryllium at least for amounts- of Be0 as high as.0.05 gm, but was very poor for the determination-of aluminium. -Since the solubility measurements made are. a l l carried out i n the presence of a certain amount of amyl alcohol, i t was then advisable to check the applicability of the hydrolysis method i n the. case--of Be in the presenee of the solvent. Known amounts of Be(N0g)g were dissolved with boiling i n iso amyl alcoholj extracted with water in a separating funnel, and determined, by Iv&nov's method. Solutions were boiled for various lengths of time to observe any effect this prolonged 'heating might have on.the,condition of the nitrate., Apparenty there i s some sort of decomposition which as the following tabulation shows, leads to inaccurate results} but the.nature.of the reaction has not been examined. Prolonged boiling with the .solvent has no marked: effect over*and above that produced by boiling merely:long enough:to obtain dehydration* (6) Table 2. Be8 added Thio used N/10 BeO found . Diff.. gm„. Comments: 0.0179 9.25 .0.0116 -0.0063 Nitrate solns. b. 0.0144 7.43 0.0093. - 0.0051 in iso amyl Co 0.0107 . 5*54 0.0070- - 0.0057 boiled just d. 0.0072. 3.71 0.0047 - 0.0025 long, enough for e. 0.0056 1.86 0.0025 - 0.0015 dehydration. a. 0.0179 8; 52- 0.0107 - 0.0072 Solns. boiled b. 0.0144 7.43. 0.0093 - 0.0051 to ensure c. 0.0107 5*50 0.0069 - 0.0058 dehydration d. 0.0072 3;62 0.0045 - 0.0027 then refluxed e. 0.0056 1.84 0.0023 - 0.0013 for 50 min. It may be seen from these values that.the hydrolysis method i s useless for the purpose. Even- worse1discrepancies were obtained for Al, treated i n a similar' manner, and consequently the possibility of using this analytical scheme'was abandoned; (b) The method involving the use of 8-hydroxy quinoline was decided upon for the'analysis, the procedure, being quite rapid, of high accuracy, and widely applicable because.of i t s non-specificity. Thus s 4 s oxine was employed i n the determination of Al,.Zn, Mg, and could be applied equally as v/ell to Ni, Co, and other Third' Group metals the solubilities of the nitrates of which were not determined-in this research. Due to the fact that-oxinates of the> metals considered are soluble to varying extents i n aliphatic alcoholsj and since a l l of the determinations were:made i n the presence- of a certain amount of dissolved amyl alcohol, i t was necessary to check the oxine procedure by the precipitation of the oxinates i n solutions containing the solvent. (7) Values of accuracy found in every case, w i l l be given -in the section dealing, with actual solubility determinations. •(c) The oxine method' cannot be applied to the analysis of Be, so unfortunately -it was necessary.to use a slower/gravimetric method. 7 The guanidine carbonate method, involving at least 12 hours.of digesting, was prohibitively slow. The tannin procedure was then decided upon for beryllium and used throughout this investigation. As i n other, methods of analysis considered, the accuracy of the-tannin procedure was determined in the presence of amyl alcohol. A standard.beryllium.nitrate solution was prepared, and varying'amounts were then taken-for analysis i n presence of amyl alcohol. In each case, 100 ml of water saturated with the iso compound were added and the determination carried" out i n the usual manner. The following values illustrate the applicability of - the.methods • Table 3, • ' • BeO.added BeO- found- Diff. gm. 1. 0.0052 0.0032 0.0000 £ »' 0.0065 0.0067 0.0002 5. 0.0130 0.0129 0.0001 4. 0.0162 0.0162 0.0000 5. 0.0227 0.0230 0,0003 6. 0.0324 0.0325 0.0001 7. 0.0487- 0.0485 - — 0.0002 8. 0.0649 0.0653 0.0004 It i s apparent from this that presence of the solvent has no marked effect of any kind.on the determination, and i t was hardly to be expected, that'it would* 9 (d) Analysis of iron was carried out using hexamethylene tetramine. (8) lo Chromium was analyzed, by the persulphate method..Methods are described i n the section- dealing:;with actual- solubility determinations. Solubility Determinationsr 1. Beryllium; nitrate-i' Varying weights of the - crystals were treated with.about 50 ml of the solvent, and the whole evaporated to a volume of about 15 ml. In the case of secondary and tertiary compounds> evaporation was carried out with a second portion of the solvents, to permit dehydration; For secondary amyl there was.a crystalline residue-indicating that the solubility of the nitrate in this particular:solvent"had been exceeded. Measurements made with- large and.small amounts of. beryllium nitrate indicated a more- or less.constant value for the solubility; however, in the case of normal, iso .and tertiary compounds}, no limiting, solubility could be ascertained. The value of 0.045 gm of BeO per ml as determined and reported by Browning and Kuzurian was far exceeded, the resulting solutions merely becoming increasingly viscous. Accordingly,.for these investigations> viscosity of the solutions was estimated by measuring efflux time from a glycerine-water calibrated viscosity tube, and the viscosity plotted against concentration of BeO. Eventually with higher concentrations the solution becomes too gummy to permit f i l t r a t i o n , even though the extent of the solubility.is indefinitei so. i n the accompanying graphs the estimated maximum concentration (and hence the maximum viscosity) which would permit efficient f i l t r a t i o n through coarse f i l t e r paper is noted. Beryllium nitrate solutions were.not filtered (except i n the case of the secondary amyl) since-the compound was found to be completely soluble i n each determination, but ordinarily in a separation procedure, f i l t r a t i o n would be badly limited by the viscosity. As was (9) mentioned beforej normal and iso amyl alcohols were found to be by far the most satisfactory of - the isomers for this work, and consequently i n subsequent determinations only the solvent properties of these two are to be considered. Since•normal and iso compounds behaved very similarly in-case of beryllium^ -only the iso amyl was actually employed in making solubility measurements of the other nitrates. It is to be tacitly assumed that normal amyl behaves in an.identical manner. Upon dissolving the portion of beryllium nitrate, the resulting solution is cooled to room temperature, exactly 10 ml removed with a pipette-and -transferred to a 100 ml. separating-.funnel for extraction with four 90 ml portions- of water. The extraction is then made,up to 500 ml in a calibrated flask and- suitable amounts of the-diluted.solution taken for analysis by the tannin method as described by Nichols and Schempf. Slight modifications made in this tannin procedure are as follows: i n the f i r s t place, the pH is adjusted prior to digestion to the isoelectric point of Be(0H)g (pH of 7.5) by means of a potentiometer with"glass and calomel electrodes, rather than by the use of litmus indicator; and secondly, 15 it grams. of.NH^NOg i s added to each solution in a total volumes of 300 ml, before the pH is adjusted by addition of NH^ OH. The ammonium-: nitrate seemed to improve and- hasten the f i l t r a t i o n of the bulky precipitate by removing a l l tendency of the precipitate to pass-through the . f i l t e r . Precipitates filtered on Whatman f i l t e r paper No. 50, using suction, were pre-dried i n an electric oven at,HQ°G for £ hours or more, and ignited in platinum crucibles to BeO i n the usual manner. It was shown (table 3) that- influence of as much as 100 ml of iso-amyi-saturated water .(equivalent to about £.7 gm. of the alcohol) was negligible, so no correction was necessary for this factor i n the (1G) solubility measurements made. Correction for the volume occupied by the solute, however, was considered advisable. This correction though, i s at best only an approximation* since density of the nitrate considered as anhydrous, is estimated by extrapolation of ; nitrate densities from the Periodic table; The series employed- was: Ba-nitrate, Sr-nitrate, Ga-nitrate| densities of the anhydrous nitrates plotted against atomic weights. The result for Be(NQg)g was density: 1.55 gm. per cc. Also, i t i s assumed that say 1 ml of solid Be(N0g)g w i l l continue to occupy 1 ml in the dissolved state, this never being exactly the case. The various arithmetical adjustments necessary are obvious, and are only summarized in tabulations to follow-; '• ..Table. 4 (a) normal amyl: Efflux time Viscosity .Vol. tafcen Soly. Gorr. Gorr. 20 deg. ., c.p. for anal; BeO TJncorr.; Vol. SOly. 1. 59 5.2 100 0.0075 0.0057 0.987 0.0038 2. 75 7.0 100 0.0146 0.0075 0;975 0.0075 5; 97 9.5 100' 0.J327G 0.0l35 0.954 0.0142 ••4r. 180 21.5 100 0.0546 0.0273 0.906 0.0301 5e 275 34;5 50 0.0551 0.0331 0.887 0.0574 6. 390 49.5 ' 50 0.0402 0.0402 '0.862 0.0466 'K - 500 62.7 50 0.0459 0.0459 0.843 0.0544 •8s- 720 85.5 50 0.0530 0.0530 0.818 0.0648 9. 1180 122.0 •50." 0.0606 0.0606 0.792 .0.0765 10. 2064 200 # 50 0.0777 0*0777 0.734 . 0.1060 (#- approximate-viscosity) . In above tabulation, efflux i s measured i n secondsj viscosity in centipoisesj and "Corrected Volume" column refers to corrected unit solute volume. Solubility i s i n grams of BeO per ml. (b) iso-amyls Efflux time Viscosity Vol. taken Soly., Corr. Corrected c.p. for anal. BeO Uncorrr Vol. Solubilii I... 61 5.8 100 0.0089 0.0045 0.985. 0.0046 z. 82 8.0 100 0.0170 0.0085 0.971 0,0087 3. 107 11.0 100 0.0262 0.0132 0.957 0.0158 4. • 117 12.0 100 0.0286 0.0143 0.951 0.0150 5 m 180 . 21.5 50 0.0239 0.0259- . 0.918 0.0261 6. 285 35.5 50 0.0550 0.0350 0.880 0.0398 7. 390 50.0 50 0.0585. 0.0385 0.868 0.0444 8. 452 56.5 50 0.0407 0.0407 0.860 0.0473 9. 635 77.0 50 0.0488 0.0488 0.833 0.0586 10. 819 94.0 50 0.0536 0.0536 0.816 0.0656 (g) secondary-amylr In this case* so l u b i l i t y can be exceeded, leaving a crystalline residue, after boiling three times with the-solvent (total volume used being about 50 ml) down to a volume of about 15 ml. Solutions were filtered on Whatman #1 f i l t e r papery and filtrate-analyzed as before. Viscosities of fil t r a t e s were measured, and for the small amount which did dissolve, there- was negligible increase in viscosity over and above that of the pure^ solvents Varying weights of the crystals were taken, and the followingresults obtaineds Efflux time 20 deg Viscosity Vol. taken c.p. for anal.' BeO Soly, Uncbrr. Corr. Vol. Gorreeted Solubility 1. 22 2.0 50 0.0121 0.0121 0.958 .0.0127 2. 23 2.0 50 0.0116 0,0116 0.960 0.0121 3. 22 2.0 50 0.0117 0.0117 0«,9"6& 0.0122 j (12) j The average value obtained for the solubility i n secondary amyl i s 0.0125 gm. BeO per ml. (&).tertiary-amyl; Efflux, time Viscosity Vol. taken. Soly. Corr. Corrected 20 deg. o*p«. ' for anal. . • BeO Uncorrb Vol. Solubility 1. 63 5.9 100 : 0.0066- 0.0033 0.989 0.0034 2. 87 8.2 100 0.0156 0.0078 0.973 0.0080 5. 132 14.0 100 0.0178 0.0089 0.963 0.0092 4. - 155 17.0 100 0.0218 0.0109 0.961 0,0113 5.- 262 33.0- 50 0.0215 0.0215 0.926 0.0232 6. 599: 50.2. 50 0.0511 0.0311 0.893 0.0348 7. 596 72.5 50 0.0594 0.0394 0.865 0.0455 The curve for calibration of the viscosity tube i s incorporated as f i g . 1» It is to be pointed out, without delay,, that the viscosity values given in the preceeding tables are by no means accurate. They are probably correct to within 5% in the range up to about 50 c.p«, but beyond that value-, they are merely estimations. The curves drawn (fig. 2) therefore, would require complete revision i n any future work concerned with the application of the viscosity method to quantitative analysis. However, i t is rather apparent from results obtained, that there is • a consistent relation between viscosity and the amount of beryllium nitrate dissolved. Not included i n this report are measurements of the viscosities of beryllium nitrate solutions taken at approximately one day intervals over a period of one. week. It was found that there.was no change: i n viscosity of the solutions i n this length of time* providing of course that the containers were kept stoppered to prevent evaporation. No explanation is advanced for the shape or the differences i n the curves plotted i n f i g . 2. _LZTi DRTR _ 1 \ £ 0 _ _ .LOO : Substance . Spec G>ca\/- EFFlux (sec.') l o o Watar GVyc.-v/ator 0-9999 V. 17GO U 9 o 4 1-2.1-2.1 l& V<ot 2 4 4 5 7 7 t 30.3 SO < </> n 0 in c 2nVv poi -ses F rom c r i t i c a l 1 a b \ « s -•• • • • •• • S o <bo tP -H -< /•*» « -+• -• _ ' y S • • . 4 0 4 9 0 o ( O > K >0 Z< >0 3« >0 4< E F F L U X 2 >o . 6 T \ r \ E ( s e 5 dec). C . >o 8< >o 9c 1 IOO 3 8 3, s_ v.. N V do o "w or eg co oo E E e o- cr <r ^ Ci V V v • \ \ \ V E It i o t _ -0_ O.Q54-. 0_ 0 0 \ Y \ \ v --^ V \l VtSCOS TV Ccerdipo'vSes) c- : 0 HI v. 3 I I (13) (2 )Alumiriium Nitrate t The treatment formeasuring solubility of.Al(KOg)g and other compounds consider.ed,was precisely the same as that for Be(NOg)g| the methods of analysis of the solutions, however, were varied for the particular case. In every instance, where:filtration was necessary, Whatman• 0. f i l t e r paper "was used to remove the excess solute. Aluminium was determined by the oxine method as mentioned earlier in this a r t i c l e | no modifications being made i n the standard procedure. Since determinations were- carried out i n the presence of the amyl alcohol the effect of the solvent upon the1 solubility of Al-oxinate was f i r s t noted; Following analyses were made; in the presence of 100 ml of water saturated with isoamyl alcohol:at room temperature. Tablev 5 AlgQ s added KBrQg-KBr N/10 A1 P0 5 found Diff. gm. •' 0;0021 2.83 0.0012 - 0.0009 0.0042 8.00 0.0034 • - 0.0008 3 e 0.0065 13.58 0.0057 - 0.0008 4. • 0.0087 19.98 0.0085' - 0.0002 5. 0.0109 25.15 0.0107 - 0.0002 6. O.OL53 35.95 0.0155 0.0000 7. 0.0218 51.48 0.0219 •i-0.0001 8. 0.0327 78.04 0.0332. '+• 0.0005 (1 ml KBrOg -KBr N/10 = 0.0004254 gm. A^0 5) For the larger amounts, of AlgQg (e.g; #7 and #8) i t appears that the bulky precipitate of Al-oxinate tenaciously absorbs small amounts of the excess oxine which cannot be removed even with prolonged washing with hot water. These absorbed: amounts of oxine tend to offset the loss-due to (14) solubility of the precipitate i n iso amyl alcohol, and the net result i s positiveo However, for the amounts of Al which were determined i n the following solubility measurements (less than 1 milligram), i t was taken that the loss due to the presence of amyl alcohol was of the order of 1 milligram. This correction i s incorporated in the tabulations. Amounts of Al were so small that correction; for the volumes they occupied was unnecessary. Reagents Na^SgOg and KBrOg-KBr both N/30 were employed. The-filtrate from-each boiling was extracted with water i n a separating funnel as-before, and the entire.extraction taken for analysis. Table 6 (a) .normal SMJII Vol. f i l t r a t e KBrOg-KBr N/50 AlnCL found Corr-. Soly. .1. 5 1*83 0.00026 0.00126 0.00025 2. 5' 1.65 - • G.00025 0.00125: 0*00025 3. "5 1.22 0.00017 0*00117 0.00023 4.. 5 1.30 0,00017 0.00117 0.00025 (b) iso amyl; Vol. f i l t r a t e KBrOg-KBr N/50. AlgQ ? found. Corr. Soly. 1. 5. 1.70 0.00024 0„00124 0.00025 2. 5- 1.30 0*00017 0,00117 " 0.00025 3 . 5 1.95 0.00028 0.00128 0.00026 4 S 5 1.14 0.00016 0.G0116 0.00023 Very similar values were found for secondary and- tertiary alcohols, measurements being made at room temperature. (Filtered at room temp.) It i s to be emphasized that above results which seem to indicate a solubility of \~ of 1 milligram- of A^Og per ml., are very approximate. The correct value i s doubtless of this order of magnitude, though, and (15) the figures given serve as a basis of comparison of solubilities of Be and Al nitrates, and indicate: that a separation using this scheme can very easily be effected. Measurements of solubilities were then made in the presence of varied amounts of Be(NOg)^ i n solution. The concentration of BeO in each case was determined using tannin. A marked increase i n solubility was observed| and the Al(H0g)g resisting f i l t r a t i o n was plainly colloidal.in nature; flocculating within about three hours standing, and settling to the bottom of the vessel as a fine white residues Filtration through a Whatman #1 f i l t e r paper•immediately after boiling and cooling thus involved a passing of considerable amounts of Al through the f i l t e r . Since the value of this method of separation would l i e i n i t s rapidity, the actual measurements made, for purposes of comparison? were on the basis-of f i l t r a t i o n immediately after cooling. Again i t is to be noted that a finer f i l t e r ; perhaps asbestos and glass.wool, or a Gooch crucibley or even finer f i l t e r paper using suction; would result in a better separation. It was impossible to use suction i n any such determination, since evaporation of the f i l t r a t e resulted, and the primary purpose was to jjeasure the actual solubility. In an application of the method, suction.could be employed, for either qualitative or quantitative analysis, and the residual aluminium nitrate could be washed with HgO-free (freshly boiled) amyl alcohol, to remove Be(Npg)g adhering. The following tabulation illustrates the effect of the presence of beryllium nitrate upon the 'solubility of aluminium nitrate. Filtrates exactly 10 ml in volume were extracted and made up to 500 ml; and then in aliquot portions, both Be-content and Al-content were found. Summary of the tabulation ^ appears in f i g . 5. (16) Table 7 isoamyl alcohol; BeO Vol. e: cone. anal. 0.0075 150 2. 0.0098 150 3. 0.0120 150 4. 0.0152 150 5. 0.0207 100 6. 0.0266 100 To 0.0384 100 8. 0,0444 . 100 5.15 0.00134 0.00234 05,007870*0008 3.20 G.00157 O;00257 0*0080• 0.0008 4.00 0.0017-1 0.00271 Q.TOG907 0.0009 4.75- 0.00202 0.00502 0*0101 0.0010 8*29 0.00555. . 0,00453 0.0227 0.0023 10.84 0.00461 0.00561 0^0281; 0.0028 12.20 0.00519 0.00620 0.0310 0.0031 16.19 0.00689 0.00790 0.0595 0.0040 # this' solubility i n grams per- ml i s not corrected for volume occupied by either solute. It merely represents', then, the actual amount of AlgOg associated with given concentration of BeO. The second column refers to the-volume of the extract analyzed} the f i f t h column represents the correction-for solubility of Al-oxinate i n isoamyl alcoholj assumed to be constant throughout the range. It i s to be concluded from this investigation that use of larger amounts of solvent would undoubtedly lower the amount of Al-nitrate carried throughj due to the decrease i n concentration of BeO. The process i n an actual separation would necessarily involve f i l t r a t i o n through a" fine f i l t e r using suction, and washing the residue as previously prescribed. It would be advisable to l e t the solutions stand for over three hours, in any other case, i n order to permit the colloidal aluminium nitrate to flocculate«TFiltration could then be effected i n the manner adhered to in this work. o o d 01 6' 8 c -g icr_ is lo 0 0 "X, \ O.OS4 ••• V/> —J 0 to—0i_ 0 Ci 6 8 CD CC O «> ID 3Q cp. <v£> 0 > S V • &. ft-rt> (TO* \ © \ Solobi \'»ty HV1 a o /mV. «4 o (17) (5) Zinc Nitrate; Zinc behaved i n exactly the same manner.as beryllium,, the nitrate being seemingly indefinitely soluble i n isoamyl alcohol, the only one of the four dsomers employed as a solvent. The viscosity of solutions increased greatly as the concentration of Zn(NOv-)o was increased, and again viscosities.were approximated, and plotted against concentrations. (See f i g . 4). •The method-/.of analysis, .after boiling;.and-extraction i n the manner previously described for Al and Be> was the oxine method. In the f i r s t place, effect of 50 ml of-isoamyl saturated water on the analysis was determined* • Table 8 ZhO added KBrOg-KBr-N/10 ZnO found Diff. gm. -L«: 0..QG63 5.60 0.0057 ' -0.0006 2. . 0.0127 11.69 0.0119 —0.0008 5. 0.0190 18.00 0.0183 — 0.0007 4. 0.0255 24.55 0.0250 -0.0005 5, 0.0318 ' 30.45 0.0310 -0.0008 6. 0.0382 36.63 0.0575 -0.0009 7. 0.0510 48.82' 0.0497' -0.0013' 8. 0.0637 61.49 0.0626 -0.0011 (1 ml KBrOg-KBr N/10 S 0.001018 gm. ZnO) - 0.0008 Average. In this case there seemed to be no indication of absorption of excess oxine by-large precipitates of Zh~oxinate>(values 6, 7, and 8), counter-acting the effect of obvious solubility i n presence of the iso-amyl solventj so the average of the eight-values'was taken, and the figure 0.0008 used as the correction in the work to follow. (18) Solutions of Zn(N03)g i n isoamyl, of varying concentrations, were then prepared in the usual manner$ and their viscosities determined. Also, as before, 10 ml samples were extracted and made up to 500 ml. Correction i s made for the volume occupied by the dissolved nitrate the density of the anhydrous nitrate being estimated from the Periodic Table (Series: Hg, Cd, Zn,:Mg), to be 2.50 gnu per cc. Table 9 Efflux 20 deg Vise, c .p. Vol. for KBrOg-KBr analysis N/10 ZnO ZnO Gorr. Soly. Uneorr. Corr. Vol. Gorr. Soly. 1. 71 7.0 50 24.81 0,0252 0.0260 0.0260 0.970 0.0268 2. 96 9.5 40 25.06 0.0235 0.0243 0.0304 0.965 0.0316 3. 122 15.0 30 27.06 0.0275 0.0283 0.0473 0.945 0.0501 4. 125 13.0 30 28.81 0*0295 0.0501 0.0502. 0.942 0.0555 5. 145 15.5 20 0.0228 0.0234 0.0585 0.952 0.0627 6. 200 24.0 20 28.05 0.0285 0.0293 0.0733 0,915 0.0802 7. 246 31.-5 10 16.95 0.0172 0.0180 0.0900 0.895 0.1000 8, 408 52.0 10 21.04 0.0214 0.0222 0.1110 0.872 0,1271 9. 560 69.5 10 23.55 0.0239 0.0247 0.1255 0.856 0.1442 10. 782 91.0 10 26.25 0.0267 0.0275 0.1375 0.840 0.1657 - In this tabulation, solubility is again expressed in grams of ZnO per ml. Again i t i s to be emphasized that these viscosity values are only approximate. If the "viscosity method" of analysis i s applicable in the case of beryllium, then i t would also be feasible for analysis of zinc in view of the similar behavior. A given concentration of BeO produces far greater increase i n viscosity than does the same concentration of ZnO, comparing f i g . 2 and f i g . 4. For a concentration of ©.06 gm per ml of each, we get a value of appx. 80 cp.for BeO i n isoamyl, and appx. 17 cp f or ZnO i s isoamyl. Fve. 4-c 0 0 0 ••• '00 o 0 - ™. ,. .Nt~ .. _ 'N • V V 1 6 ' V: 1 V <f • IV' '• V \: . . . \ s \ \ ' \ ' .. \ 0 \ \ \ : \ \ \ •' \ V . 0 0 \ > «|m-/ml. ZnO-8 SI \ v • • \ \ - \ A • \ A 8 SI 0. 0 ¥> A-| i . i cr ? • ••• V A '! . ' V . \ \ "•V. 'A N 0 ' 0 0 *• ID '" . IJ ii 0 C 0 « 0 •-I \ \ •:' <\ \ : -V V A 6 . • ' ' '1 \ 6 c< 0 ses), a « 0 • \" > ft o o c 0 0 : a 0 (19) (4) Magnesium Nitrates The Mg(NOs)g behaved in the same manner-as nitrates of Be and Zn. Analysis was by the oxine method; Effect of 50 ml of isoamyl saturated water upon the analysis i s given as follows: Table 10 MgO added, KBrOg-KBr N/10 MgO found Diff. gm. 1. 0.0030 5.75 0.0029 - 0.0001 2. 0.0060 11.31 0.0057 - 0.0005 5. 0.0120' 23.85 0.0120 0.0000 4. 0.0240 47.22 0.0238 - 0.0002 5 © 0.0361 71-.23. 0.0359 — 0,0002 6. 0.0481' 96.23 0.0485 4-0.0004 Differences observed were very slight and not consistently positive or consistently negative, so i n the work to follow, no correction was made for solubility of Mg-oxinate i n isoamyl .alcohol. Table 11 Efflux 20 deg Vise, c p . Vol. for analysis KBrOg-KBr N/10 MgO Soly. Uncorr, Gorr; Vol. Gorr. Soly. 1. 113 12.0 20 8.43 0.00424 0.0106 0.979 0.0108 2. 112 12.0 20 12.18 0.00614 0.0154 0.970 0.0159 3. 162 19.5 20 16.23 0.00817 0.0204 0.960 0.0213 4. 245" 31.0 20 22.70 0.01142 0.0285 0.944 0.0302 5. 294^  37.5 20 24.11 0.01215 0.0304 0.940 0.0324 6. 330 42.5 20 51.96 0.01609 0.0402 0.920 0.0437 7. 798 93.0 10 26.45 0.01534 0.0667 0.868 0.0769 8. 962 107.0 10 28.31 0,01428 0.0711 0.859 0.0829 .(1 ml KBrOg-KBr N/10 = 0.000504 g MgO) Density of anhydrous Mg-nitrate i s extrapolated as 1.98 g. per ml., 8 0 o aJ—^e-01 —E-0 •0 £ 5-W. N MA. 0 6 c 0 <J 0 v t X 8 Tig. S d -JOB .0 \ O-OSgfe gcr>./crA. HqO A V \ 0 -o O o: v5 s (20) and this value i s used for "corrected volume" calculations. It w i l l be seen from f i g ; 5 that for a concentration of 0.06 gm; per ml of MgO, we get a viscosity of appx. 65 cp; as compared with Values of 17 cp for ZnO and 80 cp for BeO. This phenomenon w i l l be discussed latere Summary of the viscosity^concentration curves for Be, Zn, and Mg appears in f i g . 6. (5) Iron Nitrate; The solubility of Fe(NOg)g in isoamyl was found to be very small; after the colloidal solution formed upon boiling was allowed to flocculate over a period of 24 hoursi After this length of time, solutions were fil t e r e d through Whatman#l f i l t e r paper. Filtration before the suspended particles settled out, resulted i n practically the entire Fe-content passing through;the coarse f i l t e r . Filtrates "(10 ml) were extracted and Fe determined by precipitating Fe(0E)g with hexamethylene tetramine. ••• (CHg)gN44- 10H20«Z-f6HeH0. 4-4NH40H Fe(N05)5-i- 3NH40H > Fe(0H)g 3NH4N0g 4Fe = 12NH40H=3(C%)gN4 A small excess of 10% aqueous hexamethylene tetramine solution was added in each case to the solutions, volume.200 ml, originally slightly acid and containing 20 gm of NH4G1. The precipitated hydroxide is filtered on Whatman#50 f i l t e r paper using suction* and ignited to FegOg. Some fi l t r a t e s (the entire extraction being taken for analysis) gave no test at a l l for Fe, not even with KSCN reagent; however a small amount of Fe was always retained by the amyl alcohol' after extraction, leaving i t orange-red In colour. In the -tabulation to follow (table 12) eases where no.f Fe^Ojawas.. found signify that no test occurred with KSSN*' • - - < V/ii 0 N 0 0 0 o V • V' x ; 'V ' N \. V \ \ . \ \ •'-\ \ •• '\ • V \ \ ID 0 \ • w" » I o 0 0 6 .... .;  . -... <L oL d. \ 0 \ _ \ S V 6 -0 o cr g ; 0 u UJ V l> o • ~ o <• r \ A \ • I 3\\ i >' v J o o <j • • j o . 8 > o o o 6> o" c O t N <^ *s \\ | \ v VV. % \\  1 0»\ 1 0 n \ASCOS\TV (cent i po»se \\ 1 V \* I 6 g 8 0 0 0 (21) Table 12 Vol. f i l t r a t e Fe^Qg found FegCy soly. 1. 10 n i l 2. 10 n i l 3. 10 0.0015 0.00015 4. 10 0.0007 0.00007 5. 10 0.0007 0.00007 6. 10 n i l It i s estimated, then, that the solubility of Fe(N0g)g in iso-amyl alcohol i s of the order of 1/10 of 1 milligram of Feg03 per ml. It would not be practical.to use this method for separating Be Mg and Zn from Fe, due to the uncertainty of the colloidal nature of the Fe, and due: to-the length of time required.for i t to flocculate. (6) Chromium Nitrate; No actual values for solubility in the case-of Cr were found. Solutions of Cr(N0g)g i n isoamyl were prepared, howevery and the behavior was very similar to that i n the case of Fe(N0g)g. Colloidal suspensions resulted, probably composed of Chromium oxide, which would not flocculate on seven days standing; and after.this length of time, continued to pass completely through Whatman #1 f i l t e r paper. The method, therefore, would be of no use i n separation of Be, Mg, and Zn from Cr. Investigation for Colloidal Properties by Centrifuging Due to the obvious colloidal nature of solutions of Fe and Cr, and Al i n the presence of Be, i t was strongly suspected that the solutions of nitrates of Be. Mg, and Zn were colloidal. Iron solutions were centrifuged and i t was observed-qualitatively that settling of,colloidal Fe^Og was quite rapid. No definite evidence was obtained, however, for colloidal (22) tendencies by centrifuging i n cases of Be, Mg and Zn. Solutions of nitrates of these three elements in isoamyl alcohol were prepared and standardized. Samples were.then eentrifuged at appx. 1500 r.p.m. for definite lengths of time, the top portions of eentrifuged solutions removed using:a pipettey and analyzed by the- methods previously described. The possibility exists that centrifuging at higher speeds would produce the evidence sought. . Results of centrifuging are. as follows: BeO Concentration 6.0181 0.0178 . 0.0179 Time of Centrifuging -0 30 min* 150 min. MgO Concentration 0.0264 0.0267 0.0267 Time of Centrifuging 0 30 min. 150 min. ZnO-Concentration 0.0208 0.0208 0.0206 Time of Centrifuging 0 60 min. 180 min. —oOo— CONCLUSIONS 1. The method involving the use of isoamyl or. normal amyl alcohols is feasible as a means of separating aluminium.and beryllium, the aluminium nitrate being very sparingly soluble, and beryllium nitrate being seemingly in f i n i t e l y soluble. The solubility value of 0.045 gm, per ml of BeO as given by Browning: and Kuzurian was found to be a very conservative figure, this concentration of BeO being far.exceeded. 2. Solutions of Be(NOg)g, Mg(N0g)g and Zn(N0g)2 i n isoamyl.(each nitrate being infinitely soluble in the solvent), become increasingly viscous as the-concentration of solute increases-and-this property could probably be utilized- i n a rough quantitative scheme* 3. It was concluded that the.boiling points of secondary and.tertiary amyl alcohols were too low to ensure "dehydration" of the solute, (23) (considerable amounts of Al(N0g)g being dissolved i f water is present), and consequently these-isomers are not recommended* 4. Filtration must be carried out using a very fine f i l t e r i n cases of mixtures of Al and Be nitrates, due to the tendency of the Al(NOg)g to become colloidal. Allowing the solution to stand for several hours obviates- this d i f f i c u l t y . 5. Filtration i s limited, although i n an arbitrary way, by the viscosity of the solution, in cases of Be, Mg. and Zn; referring particularly to the ease of Be j, i n separating this element, from Al. The limitation i s arbitrary because i t depends upon the type of f i l t e r employed* The viscosity limit for laboratory f i l t r a t i o n i s taken.as 30 cp. On an industrial scale, use of large suction f i l t e r s could accomodate media of higher viscosity than 30 cp,, thus increasing the effectiveness of a given volume of amyl alcohol i n extracting Be(N0g)g from a mixture of the nitrates>of Al and Be. 6. Upon boiling the nitrate-with the solventj the amyl alcohol takes on a brown color i n the cases of Be and- Zn$ suggesting- presence of- oxides of nitrogen, and this i n turn suggesting a certain degree of decomposition of the nitrate»: This phenomenon was not apparent in the case of Mg. The claemical composition of the solutes was not determinedi and for simplicity, throughout this work, they are considered as anhydrous nitrates. 7. The viscosities observed for Be* Mg and Zn nitrate solutions seem to be some function of the molal concentration. For instance, from the curves we have for a concentration of 0.06 gm. per ml of the oxides* values of 80 cp for Be, 64 cp for Mg, and 18 cp for Zn. This may be tabulated as follows: (24) Oxide coney gm«/ml Cone mols/liter Viscosity Be 0.06 2.40 80 Mg 0.06 1.50 64 Zn 0.06 0.75 18 This periodicity of properties, although only very roughly indicated i n the above, would probably carry throughout the beryllium-aluminium group* (Group II)* In f i g . 6, crossing of the beryllium line by the magnesium line i s no doubt an error. Further investigation would probably reveal the family of curves to be quite regular. SUGGESTIONS FOR "TURTHER INVESTIGATION ' 1. Solubility of other compounds of these elements: e.g., sulphates, chloridesy etc, inamyl alcohol, or similar solvents* 2. Solubility of the nitrates i n higher alcohols of the aliphatic series. 3. Investigation of the viscosity-concentrationrelationship in cases of Be, Mg, and Al, with a view towards employing i t as a rapid quantitative analysis method. In this method, the exact volume of the solution being-examined must be known before the viscosity is determined. Choices of methods and use of instruments i s l e f t to the discretion of the investigator. It may be added,"however, that the simple method employed i n this research would not be sufficiently reliable for exact work. 4. Determination of the exact composition of the solutes (Be, Mg and Zn) when dissolved i n amyl alcohols, 5* Investigation of colloidal tendencies by centrifuging. —oOo— (25) 6. Measurements of viscosity-concentration "relations for the remainder of Group II, Be I /*< Ca Zn I I Sr Gd I I Ba Hg I // • 7* Solubilities of nitrates of.other metals of the Aluminium and Iron groups. —-oQo— Referencesj 1. Brovming and Kuzurian:: Orig. Com. 8th Internat. Gongr.- Appl. Chem. 1, 87-90, (1912) 2. Ivanov:: J. Russ. Phys. Chem. Soc. 46; 419-427j (1914) 5. Berg and Teitelbaumtt Z. anal. Chem. 81j 1, (1930) 4. Hahn and Viewegss: Z. anal-. Chem. 71} 122^130, (1927) 5, Shuman and Berry: s Ind. Eng. Chem. (Anal.' Ed.) 9, 77, (1937) 6. Kolthoff and Sandell:: J. Am. Chem. Soc. 50} 1900f-(192S) 7, Jilek and: Kotasi Z. anal. Ghem. 87j 422, (1932) 8. Nichols and Schempf:: Ind. Eng. Chem. (Anal. Ed.) 11, 278, (1939) 9, Ray and Chattopadhya% i Z. anorg. allgem. Chem. 169} 99-112, (1928) 10. A.I.Vogel: "Text-book of Quantitative Analysis", Longmans, (1939) 570 11. Ibid?: 537. 

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