A Method for the Production of Barium Hydroxide from Barytes Citation Sheffield, Harold Clough (1925) A Method for the Production of Barium Hydroxide from Barytes. Bachelor's thesis, California Institute of Technology. doi:10.7907/tdct-qz72. https://resolver.caltech.edu/CaltechTHESIS:08082024-160329147 Abstract The inertness of barytes has led to many experiments and patents for its reduction. It was decided to effect the reduction of the barytes in a cement kiln with carbon. The temperature of the greatest yield with the least water insoluble material is between 1000°C and 1100°C and with a minimum period of heating. The yield is about 87% of the original barytes. The resulting BaS is quenched with water and ground to 20 mesh. The leaching is very quickly accomplished and the temperature of the solution is raised 80°C to bring more material into solution. The solution is then filtered, a theoretical amount of CuO added and the mixture boiled. The resulting CuS is filtered off and CuO regenerated by roasting. The Ba(OH) 2 solution is evaporated down and the solid precipitated out by cooling. The material is in the form of Ba(OH) 2 8H 2 O, and must be heated to a dark red heat to drive off all the water of crystallization. Item Type: Thesis (Bachelor's thesis) Subject Keywords: (Chemical Engineering) Degree Grantor: California Institute of Technology Division: Chemistry and Chemical Engineering Major Option: Chemical Engineering Thesis Availability: Public (worldwide access) Research Advisor(s): Lacey, William Noble Thesis Committee: Unknown, Unknown Defense Date: 1 January 1925 Record Number: CaltechTHESIS:08082024-160329147 Persistent URL: https://resolver.caltech.edu/CaltechTHESIS:08082024-160329147 DOI: 10.7907/tdct-qz72 Default Usage Policy: No commercial reproduction, distribution, display or performance rights in this work are provided. ID Code: 16620 Collection: CaltechTHESIS Deposited By: Benjamin Perez Deposited On: 09 Aug 2024 17:24 Last Modified: 09 Aug 2024 17:30 Thesis Files PDF - Final Version See Usage Policy. 6MB Repository Staff Only: item control page

A 1\/IETHOD :b,OR THE PR:ODUCtrION OF BARIUM HYDROXIDE l1~0M BARY'XES by H. C. She ff i ®ld I n parti ?. l ful f ill me nt c f the r e quir eme nt :; for the deer ee of BRchelor of Science in Chemic a l llngineering CALIFORlJIA INSTITUTE OJi' TEDHlWLOGY Paeade na ,Celifornia lS-2-5 '""' ,, t'age 7t l Aim The aim of this investi gation ha s be e n to select a precess for the commerci a l productjon of Barium hydroxide fr cm barytes, and to d e t e r mine the most favor able conditions for its oper a ticn. Abstract of Eesults The j nertnes • of b &.rytes h ::~s led to many ex- perjments a nd p&tents for its reduction. It was decided to effect the red.ucti cn of the barytes in a cement kiln with c a rbon. The temp er b.ture of the gre a te s t yield vrith the least water in- ::md with a minimum period of hea.tj_n? . The yield is a ~ out 87% of the ori ginal 02.rytes. The re- sulting BaS is quenched \Vi th w.,,,.ter 3..nd ground to 20 mesh . The leachjng js very CiUickly ?.ccomp- lished and the temper s,ture of the solution is r a Jsed 80°0 to bring more ma ~eri a l into solution. The solution is then filtered, a theoretic ~l amount of CuO added s.nd the mixture boiled. The resultin g Cu8 is fjlt <: red off and CuO regenerated by roasting . The Ba(OH) 2 solution is ev::1.porated clovrn .::.nd the sclid precipi ts.ted out t y cooling. The ~at s ri a l is in the form of 'D (01.·) · ba .i 2 gr ,; ;_z J, ana.' must ,oe heated tc ~ dark red he2.. t to drive off 2-.J.1 the '·'-'~'. ter cf cTystalli za ti on. History and Importance Barytes is a natural sulfate of ,oarhmi. It usually appears associated 1vi th silic a , lime r:vnd i:ron, and. is a very cheap source of 1:: ::,riu.m compounds, costing ~ut $5--tlO per ton at the mine and tp26 per ton 'Nhen flO ::cted 2vnd. purified. Extensive deposits are found in lii ssouri and the southern Appal a chian statea a.n::l in England. The pro"Lle,t cf re(h.i. cin c the baryte :3 to the sulfide has ·teen the s1J.bject of much inv e sti f,f-- tion E, ince about 1910 as EaS a.ri d Pao were for- merly used. for deaacch 2.rizin g- ir:o l e:.sses as CaO is use d in the Steffens process today. Cao has recently super : ;eded BaS and EaO 1ue to its 10°.ver cost and almost ec~ual desaccharizin 2: action. It was formerly thought th a t a solution c f Bas if sufficiently cooled, wouli preci p it s te Ea(OH) 2 crystals. This theory was froven erro- neous by Terres and Er"l'l.ckner 1 '/lho ohowed that a dc,uble salt Ba(SH) (OH)5H2 o separateJ out when Z.E. Zo 1--20 (192 0 ) A list of abt r(,vi 3,t 5. ons used in thj s re ~:-. ort is 6 iven on page 20 Page #3 a Bas solut:.on ·;.ras coole:i. ':!.'hus a correct met:iod of obtaining Ba(OH)a from BaS must be investigated. Materials The barytes used was the same as used by paint manufacturers and averaged 91% pure, with no iron or silica. The charcoal for the reduction of the barytes was finely powdered as this was found to greatly increase the yield of BaS. Apparatus As the first part of the experimental investigation (that of re1ucing the barytes to BaS) was well covered in the literature, it was thou gh t b est to csncentr at e effort on the seconj part, (that of convefting Bas into Ba(OH)z). No Bas was found avatlable so : t was necessary to pre- pare some, not for the purpose of obtaining the greatest yield but merely to afford material to work on. For tM. s purpose a small scale furnace vi/as designed to handle about a three pound char 6 e. It was constructed of fire brick bound together by hi gh tem0erature cement. Gas 'Nas used to fire the furn ace and a special type of burner equipped Y•T i th an electrj c fan blower w·3,s ne ede d to attain the 1000°0 needed for the reduction of the Barytes. The furnace was made just lar,te enou;::h to accomo- de.te one ize ·:r. fire cl.:..y crucible. T eory The reduction of the barytes may be accomplished in .i~her of t\lo ways . B so~ + 4C --+ Bas + 4CO Bas + B S04 + 2C or co rom the investic~tions of A. E. Wells ' it is proba le that the for er ecuat. on ~ore ne~rly re resents the facts c f the case ~nd th~t & reaction following the first e uation , ives ccnsiderably better yields than one fol owing the second . U on dissolvin~ the ~as in ,ater reaction takes lace ccordi~ to the following J . I . E . C. 8, 776 ( 91 6) " J1. •• :::age ,rb equation, Ba.S + HOH ~ Ba (SH) ( OH) as was established ty Terres and Brtlckner ' The f orrnation of this double salt and the s epa- ration out of the same upon cooling the solution made it impossible to obt ain B~(OH) 2 by this method. As suggested ~-,y Darcet and Vogel (des- cri bed by Terres and Brtickner) the sulfur can be removed from the solution by toiling with finely divided CuO. Ba(SH) (OH) + CuQ.::::;:::::::!:: Ba (OH) 2 + CuS The CuO is re generate d merely by heating the CuS above 220°C in contact with air. 2CuS + 302 -...,~~ 2Cu0 + 2S0z Proce dure As mention4d before the literature on the subject of t he reduct:i on of barytes to the sulf:i.de is voluminous and much time was S};ent on go in g over it. It was thought wise to ke ep a file of the articles on anc1,lysis of barium ccmpoun1s as well as those on the reaction itself. The bibliography follows. Z.E. 26 1--24 (1920) Page #6 M. Herzberg C.A. 2 1867 (1908) BaOz prevents the reaction BaO from going to the right. C.E. Jacobs C.A. 2 2716 (1908) A charge of DaC03 40 parts and coking coal 16 parts, finely povrd.ered produces Bao of exceptionally porous structure. C. Rollin C.A. 6 1969 (1912) Bao may be produced by heating Ba(OH)z in a furnace on the floor of which is Ba(N03) 2 . G.A. Barbieri C.A. 1 2019 (1913) A charge of Ba~o 4 , 100 kilograms, Carbon 28 kilograms, and Na2S04 7 kilograms, he~ted in an electric furnace yielded BaS, 90 • 3%, Bao 3 . 8%, BazC 2 . 6%, and Naz s l . 8%. The wa.ter insoluble material amounte:l to only l. 5%. Chem. Fab. Cosweg (P) C.A. 1 2670 (1913) Baco 3 heated under reduced pre s sure yields a very hi gh percent ag e of exceptiona lly porous Bao. L.E. Saunders C.A. 8 3841 (1914) In an electric arc furnace lined 1\•i th BaS04 -,,., i thout the use of carhon, 7 5% of i;he Baso 4 ~as ccnverted into Bao. BaS04 - - ~ BaO + SO 3 S.B. lTev{berry and H.N. Bc~rrett C.A. 9 1374 (1915,) By mixing Baso4 and Bao 1n equal proportions a nd pulverisin g till 90% :;) asses thru 100 mesh and heating and a gi tatjn g the same 1460°0 a high quality and good yield 8..t so2 and Oz are evolved of BaO is obtained. in t he process. The Bao prevents the char ge from fus i ng to g ether. R. De Forerand C.A. Ba(OH)~.., J 623 (1909) BHao is heated in a stream of Hz &nd Bao is obtained if the temper~ture is kept above 6C0°C. This article also gives the thermo-chemistry of the oxide. C.B. (Abstac- ted from A. C .P. 15 (8) 433-90 (1908) C.A. (1912) 6 2652 BaS is hi gh ly poisoncus. of BaC1 2 is 10-15 grns . A fatal dose .An investi g ation of poisonin g by barium s a lts. Chr. A. Beringer C.A. 6 3170 (1912) Soluble barium compounds may 1:,e pre- Page #8 pared by igniting a mistur e of BaS04 and an alumina and silica containj_ng substance at brii; h-t red heat. The bs..ri um,-aluminum-si- licate thus formed is decomposable by acid. H.O. Hofman and W. Wanjokow C.A. 1. 30 (1913) Abstracted from the B.A.I.M.E. 69 943. 889- Curves ar e plotted showing the disso- ci9.,tion and decomposition temperatures of alkali earth met a ls when heated in a current of dry air. W. Mosttowitsch C.A. 5 841 (1911) ?ure Baso heated for 15-30 iidnutes in 4 dry air remajns unchanged up to 14C0°C. First dissociatjon is noticeab le at 1500°C. At 1580°0 i t me 1 ts,. Decomposition of BaS04 by Si02 begins at 1000°0 and forms silicates. FeO decomposes Baso4 at 1000°c. Reduction CO be g i.ns to reduce Baso4 at 650°C and compl etes t;he re ductj_on by 800°C. BaS remains unchanged a t 1 C0°C. It loses some of its sulfur at 1200°0. J.F. Sacher C.A. I 1465 (1913) Analysis of Bas t y precipitation with en excess of Pb (no 3 ) 2 and. back ti tr :;;.tin g the Pb(N03)z '<Nith (NJI4);3Mo04. G. v a n Staszewski C. A. 9 358 (1915) Bas is ob t 1:d .Led. by heating Baso 4 in a rotary furnace in the presence of hot furnace gases p as s ing thru the furn ace i n the same di rec ti on a s the char ge. The temper- ature is maintained at 900°C. The CO is burnt and returned to the furnace, I.L. Marino C.A. 1 3302 (1913) Abstracted from G.C.I. 43-416. An electric rotary furnace is described which makes use of water gas and. illum5nating gas for the reduct i on of Baso4 a t 525°C. The gas enters at t he exit end a nd a yield of 95-98% i s clai med. W. E . Pri '3 k and n.R. Harris c-n C.A. 12 (1918) 982 BaS is purified c y filt f; rjng it s solution thru suc c essJ.ve lay er·s of MnQz a nd granulated Caco 3 . J. Wa ddell C.A. 12 1445 (19 18) Barium c a n ·oe v o lumetr i c9..lly de te r mi ne d b y me a ns c f BaCr04 and KI. 14 2314, 14 (Also S (; e C. A, 3613 for sj_mi lar me t. ho d s) . G.M. Adhikari et. al. C.A. 17 1535 (1923) Details c.nd preca.u tions for re ducj_ng Baso4 are set forth. U. 2 177 BaS04 is re'.iuced with coke and the resultin g BaS is heated. in an electric furnace ·:ri th more Baso4 to obt a in the oxide. 4BaS04 + 4C -~➔► Bas+ 3BaS04 + 4CO Bas+ 3BaS04 -~~- 4Ba0 + 4S02 Abstracted from J.C.I. 21-391 W. i 442 (1902) (Old Ed.) Add BaS to hot water, filter and add CuO or ZnO to decmmpose the.Bas. Evaporate the material to dryness and heat to red heat to o:..t a in Ba(OH)z. ;]eating Ba(OH)z in a stream of air produc es B,:,_O and I12 O. Bao is also formed by heattng BaS0 4 ,in the presence of ste am. T. l 546 (See P. 55-415.) (New Ed.) Bas is prepa red b y heatin ~ l ~O parts of BaS04 with ZO parts of co :':L l slack or charcoal. An admixture of re sj n oil or gas works for hydrogen cont a in~ng products P-a.ge =//:11 prevent the formatjon of polysulfides. The s.cldi tj_ on of cc,rnrnon salt aids fusion of the Baso 4 . A char ge of the follo·3Lng c om- position heated jn h r everber ~tory furnace gave 6 (od results; lCO parts Baso4 , 2:~o parta NaCl, and 15 parts cf charcoal. The analytic c:·. l methods for deterrnin:i.ng sulfur found were: (l) Determina.t5c,n With ?bAc2--Aft e r Tree,dwe 11. (2) Dete r mination by oxidizin g S to S04 :..y means of H2 02. (3) Volumetric determ:ir..a tjon by titration ~ith HCl usin; phenolphthalein and methyl orange as i ndicators. (4) Volumetric determinat3.on using (a) This metho d is not very accurate due to the loss of HzS from the diluted. soluticn. It is very eas ily s een that the problem r e gclves itself into t~o minor prob lems, the first tlw,t of reducj_n f; the ba:rytes to the sulfi :.1.e 2.nd the subseCJ,uent ccnver sj en c f the sulfide to the hydroxide. Page #12 Preliminary Work Some trouble was ex11erienced in ana- lyzir.:.z tie barytes. It .ims thcught ·uest to 0 follow the method of Tech ', who advises fusing one gram cf the sample Hith fjve grar.18 cf anhydrous Na2co . 3 out in a porcelain crucible. This was carried After fusing the sample was leached, until it djsintegrated, with l'."'0 c. c. of water and then The residue of Baco 3 was washed filtered. and 25 c.c. of HCl (1:3) added. After bo:i.1- ing to remove the CO 2 and neutralizing with NH40H and then making r;lif._htly acid w•i th the barium. The BaS04 was then determined in a Gcoch crucible. As the hi c:h heat (from a blast lamp) cracked one cruc:blc and the two other determ~nations gave discordant results, (differing 17%) it was ::lecjded to use a nickel crucible. was determined as it jas a d~rnagjn~ effect on 'coth n: cJ,el and plat:lnum ancl amcunted to less than a.as%. t Results 7~th the nickel Chemistry and Technology of Paints P 314 Using b.. platinum cn.."i.cible the SBX11}_;le \Va.s f cuncl to ccnt a j__n 91% Ba.S64 "'-:i th determ:i natj on Vc:Lrying less than 15~ . Po iron 01· s: lj ca was fm.rn ::1 present, the 9%· being prc'\::, a,;:,ly Baco . 3 As thjs has no effe c t en t he precess furth er analyzjng The barytes vas red1.:.ced jn the furn 1:1ce d.escribed. A mix of 10 ~ounis af tarytes ~nd 1.56 p cunds of powdered charcoal (after pr cportjons J:' C J. u; .,., .,s'I \.<;; .. L.L heated a t 1000°0 for one hour end forty-five minutes. The yield ,1as about SC%. Exnerimental Some c f t he EaS Vl'3.S c:tri ed. and run th1·u the pulverizer. j n I t was found ~hat the heat generated th£; pulverizing oxi :--lize'.i atcut 50'{., of the BaS back to Baso 4 . j n Im1.smuch as the Bas is quenched. water (or Ba (OH) 2 solution from the f j_fta.1 cryatallization) i t is more conv enient to pul- v erize ·-,et . sei:,ar :.t e fr om tt.e so LJ.ti on c f BaS dhen coo led. T~o metho~ s of obt a in~n c Ra (OH) 2 ~ere su;ge s ted. (1) By che.,nc tn€ the S ccmpcund.s with metallic Page #14 oxides as CuO or ZnO vrhich give in s olu"o le sulfides a s first advs.nced. by Dare et 2,nd Vo gel. Py ctri vin g out H...,S bv pas sing ,:;;; " a hot satur ated solution here1:,y 'bar :Jum prec:ipi tates a,s Baco 3 a.nd is chanc:ed to Bao 1-_: y heat:in?;. Te s ts rrade by Ter:·es and Bttl.ckner showed that desulfurizm.tion with CuO is comp lete and reacts This method wa s c~osen in molecular p r oportions. for the desulfurization of the Ba(SH) (OH) because it was simpler an-:1 had no difficultly _handled ga ses i n the reactj ons. On titrating , the soluti c n p repared in the laboratory w:th HCl us:ing f:irst phenolphthalein and then Hethyl or &.nge e.,s indicatd>rs to obtain the OH an ::l SH conc entrati ons resp ec- tively, it was f ound tha t they occurred in exactly e quc:,,l qua ntjt:ies. The firs ~ expe riment c onai dted in h ailin g 10 c.c. of solutj_0n and .329 [,ems. CuO (finely pov,rdered) for 20 minutes. The sclutt c n vfox; then fj_lteTed Eind titr2.,te d. '.Va s It foun:l to c r. nta:cn 20 0 c.c. of soluti on waG treate1 in a similar way, tl1e ~;ime re quj_rc;~l b ej_r_,:s 20 r.15nutes. Here le ss th an 2.5'% SH re mai ned. Another 2-~0 c, c. t1anr-:: le ,-.r'"1s treated in the Page #15 above manner and the filtrate evaporated. almost to dryness. The Ba(OH) 2 obtained was very pure and containe1 less than .24% SH. Experiments with the leaching of the BaS s howed that j t took place very rapidly thus in- dicating that the process would not be held up appreciably for the leaching operation. There was quj_te a tendency for BaC0 3 to form on the surf ace of the barium solutions ,7hile working with them. Howevc~r i.n commercial apparatus the access of air would not be so free and this trouble would not be so bothersome. It is important to note the effect of iron on the re::1.uctj on of barytes. Cor!r9a.rati ve tests made by Wells gave the followin g re sults: Percent of Total Barium in Compounds (Average of 4 tests.) Water • ·Acid Ac id Material Soluble Soluble Insoluble Pure BaS0 4 BaS04 with 6% Fe 80 10 10 68 17 15 This indicates tnut the presence of ircn in t ?1e Barytes :reduces the amount of Bas formed materially. avoided jf Consequently this impurity is to be possible. Page #16 Conclusions It is qu.ite apparent that the desulfurizatjon of Ba (SH) ( OH) c an ,ce 3,oc ompli shed on a. cornmerci '.:=t l It n c·:; rema5 ns to choose the scale 1·,y CuO. method of redu-~:n : ,?; t'ue barytcs to th,, sulfide . Many e lectr:l c arc an :j_ electric furr:2;.ce }_'.)roe c sses are prominent successful. ~ n the 11 ter e,., ture ':31Cl e,r~ a·~,-::18,rently However the hi gh c o st of electrical power expecially in thi s part of the coun try practic a lly prohibits the use of these processes. The very thorou,?h jnvest:igation c f the reducttcn of ba.rytes ty A.E. Wells 'gives Viany possibilities. Prob c.tbly the most pr act j ce.l met hod invest j g3., ted was th~t using a cement kiln. This was 12 feet long 2.nd 10 inches jnside d is,rnet 2r . !J:~rn nmr1~:J,r of revolutions ir2,.,s 1.15 :per rdnut e. The hot ga ses enter at the exit end . mai ntcLiEed at 1050°C. ~he temper a ture is The ratj o cf pulverize:!. coke to barytes is .15 ant the r3.,te of char ,; ;e is 19.1 pounds per hcur. The gas oonsumption is 5.6 c1...l1n jc feet p er m~_nute. a yj eld W:it11 tb.ese c or14J.t ~_c:ns of 87%- w~.t e r-soluble bar:ium ccrnpouncl.s was obta:ine<i. J.I.E.C. 8 776 (1916) -·e 1tJLl7 PrJ. Cl.,~, Recommend&tions The barytes and coke mixed in proper prop ortions can be pulverized in a small Hardjn ge i.Ii 11. T"::.e c en:ent kiln type of furnace s eems to "_. e suited v0,ry 'Nell "'co the re:::lucti.on :tea.ction. !.fue stack be"ses comjnc.· from the furnace at about 45O°C can ·t, e used to roast thE.:: CuS in a muff le furnace to reg·enerate CuO for the desulfurizat ion reaction. The Quenched BaS should be pulve:i:'ized v:et in a Hardjnge Hill and then leached in a system of tanks employ:ng 1::arallel flow of H o (or Ba(OH)z) 2 and the BaS. '!his may te ::i.CCompli shed 'by r:,e ans of connecting v~ts into vh 5ch th 2 1ischar ze of Ba.S is rotEtted. The solution should be at about 8O°C for best leaching conditions. The CuO and Bas solutj_on are intro::luced into a reaction chamber cLnd ar, : agi tateJ "·,y t·::ec:ms of air n,nd the mixture he a ted. for 3C rn2nut ~!.S by :in- -d.irect steevn1. A filtre...tion is now necessary to obtai.n the purest Ba(OH) 2 and prob;;.tly a rota:c~· fjlter •,rould be b est for th1s kind of precipit a te. Page #18 The solution is then taken down ~lmost to dryness :in a sa.l ting cut ev3,pora:'cor, the cryst,"1s being oentrifu ;;.•e:i to remcve ·excess solution. They a.re then 'ila.shed and dr:l.e:1. 'y me1:t.ns of 8.. tur. nel :irj_er of a controlled humid.i ty type. Suggestions Regarding Supplementary Investi~atjon The interestin g protlem rem~ins cf ch~n 2ing the Ea(OH)zBHzO to Ba(OI-I) 2 . Acccr"in c to 0. Bccuer ' the chan ge frcm Ba(OH) 2 BH,;;O to PE,(0H),:.3H?.o is ~ (..; .,.,) effected -~JY °i:) oiliE[' the solutj_t.n of Ba(OH),_. i:;; By meltin 2: cryst2.;.ls of Ba(OH)z3I·I;a0 at 120°C they are c cn Vf:Tte:1 int c Bc:1, ( CH) H 0. ,t;,,- hee. ti [,E.; t :ie 2 2 latter o.t dark reel heat Ba(OH) i(,., i·s obta,ined. To obt~in BaO it is necessary to heat Ba.(OH)-:,..., to a cl0ar wh ~te heat. The se react1ons ~nd a method for c ~rry ing them cut should prove an inter es ting conmer cial problem. The eacnomic aa pect of the prot lem s hculd offer~ fr u 'tful field of r e search. As mentioned in t ~o forms, i.e., just ss it comes frcm the Z.A.C. 47 417 (1906) Page #19 The cost of t~it~ or e " t the mj_ne : s fr om r: c r ton ac or~." ::.g to the pu1'i ty, ts t o t10 ;hi le the floatej ma terial costs a roun d $2 6 per ton. If the ~at 6rial e,s :, t come G frc1:1 t he c. : r::es does not c c- nt a ~n 2.,n excessive e.r:1c,unt of detrh:1~.ntc:tl iron it is very po ss i,cle that this form ·.,ould >e used, thus reducing the dost of rnateri&ls greatly. If too much iron ·a ere found present it mi ght "ce posaibl ,; tc c ive the ore a simple iteliminary tre a t me nt to render j _t av,.i lab le for the :process. Baryte Ore (8. t mine) $8 per ton $ .()04 per pound . 0118 pe 1~ pound Floated Barytes .045 per pound . 003 per pound. Cok e Breeze Using the ore aa it co mes fr om t~e mine the c0st of m~teri ~ls would he only $.0038 per pound sr-r o produced, .vhereas the r:te.rket pr:i ce 2 2 of the pr c iuct is $ .045 per pound . of Ba (OH) 0 Acknv.Il ed c::-:em en t The author wi s hes to expres s his whole -hearted thW1ks and u.::xrreciat:icn for the timely a :lvice o.nd counsel of Dr. fJin . t . L&,oey ::..rd f e r the op~: ortunt ty of having "been able to ·.; r ork _; jth ::rnd under the gtddance c,f him i n t his pj_ece of research. Page #20 .Abbr·eviat ions z.--Zantrallblatt U.--Ullmcm's 1cncyclopedia of Tech nj c .~~1 Chemistry J.C.I.--Journs.l of the Chemical Industry W.--Watts' Dictionary P.--Po 2:?.:A L::1orffs Arr,::.1.len de:r Physjk un:i Chemie. T,--Thor pe's Dictionary Z.E.~-Zeitschrift fur Electrochemie J.r.:r.c.--Journal of Industrial 8: Eng. Chem:l..s try :S .A.I. \I.E.--Bulletin c f thd Amer . Inst. of Hin5r:.g Eng. G.C.I.--Gazzet t ~ C~1~1e Itali$nne or ;,;ani she Cherrd e Z.A.C.--Z e itschrift f~r /I.n ' ' - Cokt2 Ol/enc:..h P u/v(tri,:t2. l..eaeh ._5 tZ f f I<Z < I Ba. 5H oH I 801/ A1fq,r !Ja{ol-l)z BH:;..O 50l,d F/oV\I' 5heef lib sftlr 0 /0 2.0 () 30 ~ ~40 ~50 6(J 70 80 10 20 .30 40 Terr/JS ancl, Briickner afN,r Ba(Ofi/4 and BaS of .50 SOLUBILITY CURVES 60 '70 80 D~gr~es CtV1figradtZ 90 &(011)2 8H2,0 100 -------------- l3o(Offt 8flz0 //0