The Chlor Alkali Industry in the

replaced by the Deacon process in which the h~-drogen chloride v-as oxidized by air over a catalyst. For both proceasc~s, thc hy- drogen chloride was ...
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The Chlor Alkali Industry in the d

United States ' I t i r tiistr,r> ol tkie intlitstrj is tracecl since the early c.nperinienta1 work preceding the first commercial instalIntion at Griesheini Electron near Frankfort, Germany, in 1888. Cnited States production capacity for chlorine has gro\+nfrom less t h a n 10 tons a day in five plants in I900 to upward of 5000 tons a day in 58 plants in 19a9, with an annual sales value of basic and derived products in excess of %00,000,000. Torld capacity for chlorine is nowestimated a t more t h a n 9000 tons a &>-, b u t because of operations well below- capacity in Europe and i n Japan, i t is chtimatetl t h a t United States production will be 60 t o 70% of total world production by the end of 1919. The three basic processes for producing chlorine are descrihed a r i d the United States capacity I>!- each is estimated. l h e xaricius t > p e s and makes of electrol! tic cells are classified.

A niap gi\ing the location of all the chlorine plants i u the

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research on electrocheinictil proct:ss~tuwhich until this tiiiic had been purely acadeniic. British patents to (look (1831), \J-$-att (1851), and Stanley (1853) are esnmples of predpnsnm 1vor.k on cells. The observations of K a t t indicate a rcniarknblc insight into the problcm which wss not appreciatod until ncarly 50 years later. Much work L K ~ Y done in England, Geriiimy, and the United Gtatos from 1880 t o 1900 when the first principled ~vcr(:being discovered. Names associated n i t h this p-riod espcci~illyirorthy of note are Hargrcavvs, Bird, Baiier, Castner, IJcQueur, Ikllner, Mathe.;, Webrr, E. -1.Allen, H. I. Alltin, I\IcDori:tld, l r o o r c , and

United States and C:inada and showing the principal chlorine-prodiic~ing areas is included. The ten largest t'nited s t a t e s chlorine producers are ranlied ilccording t o size in terms of chlorine capacity. The reasons for t h e great increase in chlorine consumption are a n a l ~ - z c i ant1 l the principal outlets for chlorine are mentioned. l l c r curl- chlorine cells are compared to diaphragm rells ani1 the differences between them are conitnentccl o n . The niore rapid growth of electrol? tic caustic socla i n coniparison to anirnonia-soda caustic soda is rliscusse(1 and comments are macle o n the future. Technological aclvances in the industrq-over the past 25 years are menlioiietl and the results of aggressive research are emphasized. .i few- predictions are made for the future.

EII,ORISE vas first produced coinnicrcially in Eiiyland about the middle of the eighteenth century. The Weldon process involving th:: oxidation of hydrochloric acid by manqancse dioxide was first used, but arouild 1870 i t brgan t o be replaced by the Deacon process in which the h~-drogenchloride v-as oxidized by air over a catalyst. For both proceasc~s,thc hydrogen chloride was produced by the reaction of salt and sulfuric acid, the first step in the LcBlRnc soda process, n-liich bcpan to clecline about 1890 in favor of the So1v:ty ammonia-sods process. These methods were w r v costly and, tyith the inwntion (about 1865) and developmcnt of the dj-iiamn, impetus was givm i o

5500

5000 4500 4000

3500 ___

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m-0

1890

I900

1910

I920

I930

1940

Figure 1. Fktiniated Installed Chlorine Capacity i n the United States Including all methodsof production

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placed by horizontal diaphragm cells developed by Ernest L e S u e u r and Charles A*. K a i t c , a n d ill 1898 the iIistitllation was moved to what is now the B r o n n Conipang's plant a t Berlin, S . H. 11e a 11 w h i l c , Herbert H. Uow, f o u n d e r of t h c great Duw Clieiiiical Company, had st,arted experimental work (1889) on thv C ~ W t r o l y t i c production of broiiiintand later chlorinth n-hich resultrd irr comniercial chlo" rine production at I8 90 I900 1910 I920 I930 I940 1950 Nidland, Mich., Fipiire 2. Number of Operating (:hlorine l'lantr i n the 1-nited S t a t e s in 1896. During Cher one tan pvr ria, this sanie period, Hamilton Y. ( ':t>t iit'i' IV:E working on the developxileiit, of a mercury chlorine Mercer. The iiistallatioii o f ~u-c~alledGriesheim cells at the, vi.11 n-hich was put into operation by the Xathicson Alkali plant of (hicsheim Electron near Frankfort, Germany (about 1888), is gcncral1~-considcrrd to he the birth of t h e elrd rolytic C'1)111p:iny a t Sdtvillt., T'a., in 1895. This installation was chlor alkali industry. rrioved to Siagara Falls in 1897 and x a s tliv start of what is The industry in the 1:riitcd St:ii(ah rc>dlydares froiii :t small 1 1 0 ~ the large p l m t of the llathieson Chemical Corporation. installation uf bell-jar ec~lls~ J Ytht. 1.:locr r o Chemical ( '~JnipRn,I' There followed in rapid succession small installations by S.1). at Runiford Falls, l I a i ~ i i~n * 1892. Thc,sli cells n $0011 R'\Yxrn,ri :at ('umberland Falls, \Iairic (1895); James Xercer, IIgiver1

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UMTED STATES I

I i L , I

CE RMA N Y JAPAN GREAT BRITAIN

7

1

W

CANADA

a

FRANCE

D D

RUSSIA

I TA LY SWEDEN

U

KOREA

P

BELGIUM

D

NETHERLANDS FINLAND

D

SPAIN

D 0 0

SWITZERLAND NORWAY BALANCE OF EUROPE ALL OTHER

p 0

I O 0 0 Figure 3.

2000

3000

W-orld Chlorine Capacity i n 1919 Tons per da). approximatr

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INDUSTRIAL AND ENGINEERING CHEMISTRY

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hil1,Mass. (1898); C. E. Acker, X a g a r a F a l k , S.T.(1899); Roberts Chemical Company, Xiagara Falls, N. Y.(forzrunncr of Xiagarx .4lkali) (1901); Penobscot Chemical Fibcr Company, Great Works, Maine (1903) ; Pennsylvania Salt Manufacturing Conipany, Wyandotte, IIich. (190344) : Warner Chemical Compsny (now Westvaco), Carteret, S . J. (1905); and the Development a n d Funding Company (now Hookrr Electrochemical Company), Niagara Falls, S . Y. (1906). There were installations by more than a dozen companies in thc first decade, most of which hay111-

Tiany

25.

li;lII>-

Snlvay Prorxesa Division, .\]lied ( 'hcwiicd arid Dye ('orprwatioii

1)eepwatrr I'oiitt, X . .I

pany

19.

\Vy:tndotte, AIich.

duuth Charleston, IT. \-a, tVyandotte, hfich. .\luriiirium ('ompaiiy of Caiiada Canadian Industries Limited 62. Canadian Industries Limited 63. ( 'anadian Industries Limited 64. ( 'atiacliaii International P a p ! ' 60.

61.

('ompany

Dominion Alkali C'ompatiy Dow Chemical Company 6 i . HoTY-ard Smith Papei, C o r r i ~ ~ n u y 68. Kalaniaaoo Vegetable Parchnirnt C'ompany

65. 66.

a

Eeported shutdown.

.lrvida, Quebec Cornn-all, Ontario Phawinignn Falls, Quebec Windsor, Ontario Temiskaming, Quebec Beauharnois, Quebec Sarnia, Ontario Cornwall, Ontario Eapanola.

Ontario

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Uow Chemical Company Columbia Alkali Division of Pittsburgh Plate Glass combined with its affiliate, Southern Alkali 3 Diamond Alkali (including 2 leased) Hooker Electrochemical Company ( 2 plants) :! Solvay Process Division of Allied Chemical 1 4, 5 , Gc and Dye Corporation (4 plants including 2 ) leased) : Westvaco Chemical Company, division of Food Machinery Corporation (1 plant) 7 ITyandotte Chemical Corporation 8 Pennsylvania Salt Manufacturing Company 9 E. I. du Pont de Nemours & Company 10 Ethyl Corporation a Tied. 1 2

i

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)

4

4

I). h l . Bare Paper C'onil.:ti,y Belle Alkali Champion Paper and F i h w ('oniyany Morton Salt Company Kational Lead Company Potash Company of .~lnierica:r Rago Chemical Company Southern Advance Hag mid Paper C'ompany

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LOCATIOS OF C H L O R I S E PL.AhTS IN T H E UN1TI.W STATES

The geographical distribution uf thr chlorin:. I'lants in tho United Stat,cs and Canada is shown in Figure, 4 and Table 11. The principal producing areas are shown by the circles, the areas of which are roughly proportional to the installed chlorine capacity in each area. From this map, it. is evidcnt that the most iniportant chlorine-producing areas are located at or n r w F r w port, Tes.; Niagara Falls, N. I-.; Wyandotte, l l i c h . : llidland, blich.; S a t r i u m , W. Va.; South Charleston, IT-. 1-a.; Lake Charles, La.; Baton Rougc, La.; Tacoma, Wash.: Pittsburg, Calif.; Akron, Ohio; XIonsanto, Ill.; SyracusP, S.T.; and Huntsvillcb, Ala. All these locations were chosen hecauez of a t least one of the following important factors: availability of c,heap salt, availability of or possibility of cheap power (hydroelrctric, coal, or cheap natural gas), proximity to markets primarily for chlorine or chlorine products, and/or ample supply of water.

Texas Carbon Induatiiw Zonite Corporation

Ro:iring Springs, Pa. Belle, 11.. S'a. Hamilton, Ohio Manistee, Mich. Rayrevilk, N. J. Carlsbad, S . 11. 1,os Angeles, ralif. Hodgc, La. Sayre, Okla. S e w Brunswick, 9..J.

R E 4 S O N S FOK G K E 4 T LSCREISE I \ U S E O F CHLORINE

Why has the us11 of chlorinf~iricrcasd so grostly i u the past 20 years'? The ans\vrrs to this question are partly txonoinic and partly cheniical. The economic answer is tho grcat drop in thi, price of chlorine xhich occurred in the twenties and the early thirt,ics, aiid iT-hieh is shown til- Figui~,:5 . Sine > 1940, chlorinc has advani.id only 37% as r ~ o n i p m dto 109% for the Comrriodity Priw Index. Thr, othtJr answer is research. The great increase in chemical usce of chlorine would never have been possible tvithout intensive research, not by one ilr t x o companies alone, but by many conipanics. ( ' t h i n e is one of t,he most active and versatile of the r,lrmenth and also one of t,hc cheapest. Its uses can be classified under thrcr headings: 1. Direct treatnirnl of a given product 2. Preparation of compounds in n-hich chlorine forms a reactive intermediate which is converted into a final product containing no chlorine 3. Preparation of produrts t o which chlorine imparts certain uniqur nnd tirsirable characteristics

The pririripal industries or us"s in the first cl arid paper industry, water purification and s:.\ragt: treatment, and testilr hlpaching, which now use over 900 tons of chlorine a

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day and account for more than 2OYO of the total U n i t d States consumption. These direct uses of chlorine consume niorc chlorine per year than wsas made in 1929, yet their share of tlic totnl chlorine production has dropped from 68% t o less than 24% during the past 20 years. E n d products containing no chlorine but niadi: by procc~ssL3 emplol-ing chlorine n o r use o w r 1400 tons of ehlorinc, a day, about 30y0of the total chlorine produced. Tetraethyllead. et,h,-lene glycol, phenol, and magnesium account for almost 1000 tons of chlorine a day. The first three of t.hese products l i ~ v been i~ major chlorine consumers during the past 15 years antl their expansion has paralitled that of the chemical industry as a n IioIc. ification t h a t n-e must look for the SOUTCC of the phenomenal growth of chlorine in chemistry. In 1929 only about 67Gof t h chlorine used appeared in the fini.chcd ploduct. Today, :It lmst 40y0 of it, is found in this group, accounting for more than 1600 tons a day. One field alone, vinyl and vinylidene chloride polymers, was virtually undeveloped 15 but now uses close to 300 tons of chlorine a day. The have gained their position because of their nonflammability, excellent resistsnci. to n-atcr, solvents, and corrosive solutions, high st,rength, and versatility in processing. Chlorine is also u ~ c dto impnrt, thcse characteristics t o other products such as chlorinated paraffin and chlorinated rubber. Another major use where the chlorine remains in the end product is in chlorinated solvents, with strong competition between rarhon tetrachloride and trichloroethylene for the dominant, position. Their superior solvent power and nonflaniniabilit,y haw enabled them partially to replace previously used pctrolnuni solvents. dnother rapidly expanding field for products containinp chlorine is t h a t of insecticides, fungicides, bactericides, and herbicides which no!y use upward of 200 tons of chlorine a da,y. As more information is acquired about the special propi:rtior inipnrtcd to compounds by chlorine, a continued cstrrision and expansion of its use can he cspt’ctcd. Recently, a n interesting classification of chloriiie iis(:s and outlets hap bccn made, bawd upon tlit: amount of chlorine, for t*ac1i

Vol. 41, No. 10

tiutlc,;, (-I,,> L.‘igurc 6). Thcri* iii:ty sonic inacl.ur:u thc,scj !ists, f>utit is iJ,tlic\-i,iirlint t l i r * y ari’ roughly eorrc3ct. T h stiiilj- has dwclnpi~iltho fact t h t thcsre are about clevon outlcsts for r!iliiriii(>, c’:~chof xliicli ni:iy u w ovcr 100 tons of c!iloi.iiiis :I (l:i>-, :irirl ~ ~ l i i i tot:cl ~ l i nbout 2500 tons of chlorine n d:ry. Of ingle! chlorine u+(brstill seenis to b e thc 1)iiIp -, irlicw the chloririr: is used :is a blc~ai*hing u i i follow in a1)prcisimately t,his order: et livlenc’ or iiiiscd c~thylenoanti prop!-lcne glycols, carbon tctracliloiiclc-. ~i~oiirichlori~l~i~~izcni: (in part for phenol), triehloroethj-li.iii,, vinyl rliloritlc, s:iiiit:ttion (w-attsr iiiid ecirage treatment), i~iliyi i?thylrne dichloride, broiiiiri~* cliloriclc (1:trgely for ti,trsc’th~-lli:flti), :ind brun?itliTs, antl Jxiagiit~siiini nietitl. The first in thi probably uw; iipim.rtl of 600 inns of chlorint~a tiny, ~ h c last may bc arounil 100. The nest qroiipiiig; ~rliicliiiic.lud(~i:products or u\ca r:tngi!Ix from 99 d u w i to 20 toils o f clilorim~(i day, inelurlcs 31 differi-i,l items a r i d ncconiit- for ovc’r 1090 tori‘ .if vhlorinc’ :I d:ty. -1niorig t!ie USE i n this g r o u p arc: syiitlii’tic glycerol, thi: niqny chlorotolucncs and tlcrivativcs, sot1iu;n liypochloritc, nicthyl ehloriili,, alumiiiiiin chloride. keryl lienzrnes, nionochloroacetie :ici(l, nipthy1c.nc chloride. butn~lii~iii~, x.inylitlenc chloride, p-dit~liloriihonzene, pcrchloroi.thvleiit, DDT, hydrochloric acid, ehloroforiii, benzcne hPraehloritle, chlorinated psraffin, amyl chloritlc~s,ciilciuni hypochlorite, nietal refining, pentachlorophenol, o-tlichlrrn 1henzcnc, 2,i-diehlorophenosyacetic acid (2,4 D), clilo~inuti~rl diphenyls, bleaching powder, textile bleaching, and fi)nd j)roccx-ing. The third grouping, which runs from 19 domi to 1 ton of chlorine a clay, accounts for just under 200 tons of chlorine a day, anti includes 30 different uses. The largrr and better knon-n n f these uses arc: diehloroeth?-1 t~ther,the: various silicones, sodiuiii chlo~itc~, acrylonitrile, chlorin:~tedcmnphenc, thc sulfur chloridm thionyl chloride, sulfuryl chloride, trichlorobenzene, c’nloririatc~tl naphthslenes, ferric chloride, bis(methoxyphenol), trichloroethane, chlorinnt~tdrubber, chlordan, shellac proccs>ing, titaniuni t!iosidfb. phosqnc, and nylon intermtdiati~s. UCI’ O I

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INDUSTRIAL AND ENGINEERING CHEMISTRY

The fourth group, which consists of uses t h a t account for less than 1 ton of chlorine a day each, includes something like 100 known products which total about 150 tons of chlorine a day. These four groups account for about 4200 tons of chlorine a day, and t h e figures given were based t o a considerable extent om published statistics for the first 6 months of 1918, when the average daily production of chlorine was 4193 tons a day. The production of chlorine rose to the record figure of 5000 tons a day in December 1948. It is probable, therefore, that many of the chlorine-use figures in this analysis increased substantially in the last 6 months of 1948. T h e companies which h a w played a major roll in developing big uscs for chlorine in the manufacture of other chemicals are: DOK,Carbide and Carbon Chemicals, D u Pont, Shell, Jefferson Chemical, Ethyl Corporation, Kyandotte Chemical, Sllied Chemical, Penn Salt, and Hooker. I n the case of some of the biggest chlorine-coiisu1ning product’s such as ethylene glycol, the chlorine is merely a Iiieaiis to a n end; it does not appear in the finished product, but comes out as calcium or sodium chlorides xvhich are wasted. I n other products, such as nionochlorobenzene, half the chlorine goes into the finished product and half comes out as by-product hydrochloric acid, or as in the case of trichloroethylene, two thirds appears in the finished product and oiie third is n-asted a s calcium chloride. Then again Jvlien ccrtain unsaturates are chlorinated, all of the chlorine used reappears in the finished prcduct. h great ninny of the peacetime uses for chlorine were also n-ar uscs, such as ethylene glycol for niotor antifreeze, trichloroethylene for metal degreasing (automotive and airplane engines, metal parts, etc.), purification of cotton linters by chlorine and caustic for guncotton, carbon tetrachloride for fire extinguishers for plani.n, tanks, ships, etc., Freon for refrigerators and mosquito sprays, DilT for killing insects, chlorine for the production of magnesium for airplanes and incendiaries, and tetraethyllead for aviation ymoline. On the other hand, a great deal of chlorine n‘as used in the n-ar cffort in ways t h a t have very little, if any, peacetinie counterpart. Essmplcs of these wartime uses of chlorine are: hexachloroethane for snioke screens, sulfur chloride and arsenic trichloride for war gases, chlorine for the prepnrittion of fluorocarbons for the atomic bomb project, cable coatings for degaussing and other cables. and chlorinated paraffin and other chlorine-containing or using rompounds for uniform impregnation to protect against war gases. CHLORIVE IVSTITUTE AND ASSOCI 4TIOY O F A1lERIC.4U RAILROQDS

A4iiystory RlJOUt the chlor alkali industry in t h r criited States vi-ould be incomplete without mention of the Chlorine Institute, which organized in 1924, and recently eekbrated its silver annivers:iry. Robert T. Baldn-in has bcen its able sccrctary from the start. The Chlorine Institute has bei,n a m o j t iniportant and constructive factor in dc loping snfr practices in the handling of chlorine, as evidenced by the fact that otil~*one fatality has occurred in connection with the shipriient of many millions of tons ~i chlorine during the past 25 years. This is a most outstanding safety record and the Chlorine Institute, its Coninlittee on Container Specifications and Safety, arid the -issociation of iimerican Railroads with its Bureau of Explosives and Tank Car Comniittee are t o be comniended for the important part they have played in it. The scale on which chlorine is noF being shipped can be illustrated in no better wag than by showing the number of containers now in use (supplied by the Chlorine Institute). Chlorine cylinders Ton drums hlultiunit underframe cars 16-ton single-unit tank cars 30-ton single-unit tank cars 5.5-ton single-unit tank cars Known chlorine barges 2 barges, 380 tons per barge 8 harzeq, 600 tons per barge

165,000 (est.) 18,000 (est.) 297 432 1,004 310

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3lERCURY .A>lALGAAI CELL VERSUS DI4PIIK.4GIf CELL

Although only about 77, of the total Uniteti Stntcs production ~f chlorine is made in m:.rciiry cells, in Canada about 70% is nou- niade in mercury ci.l!s and these cells accountod for ahout 60% of Germany’s peak wartimr production (1942), which pcrcentagc would have increas-d to about 71 if the capacity projected for 1944 had been reslized. There were sweral reasons \Thy the Gcrmans favored the merrury eel! for their rvar expansion of chlorine capacity. The principal diaphragm cell then used in Germany mas the Billiter cell. iilthough i t was modified and improved greatly in some German plants, on the average i t cijuld not b:. compared to the bot’ter diaphragm cells in the United States, nor with the mercury cell in its then highly developed state in Germany. Steel and nickel needed for caustic evaporators for diaphragm cells were critically short, and the right kind of asbestos for diaphragms was not arailable. There n a s also a rumor t h a t Hitler had made smile sort of a den1 with Spain rvhereby the Germans wvere able to yc’t Spanish mercury very cheaply. I t is probable t h s t the great amount of developnicnt xork the Gvrmans had done on mercury cells and the extent to n.hich they had perfected them and tlicir perationwere also very real factors. Conversdy, the availability of high grade asbestos and nickel, the necessity of importing mercury from outside this hemispherve, and the great amount of development work on diaphragm cells and on c:tustic soda evaporation and purification h a r e been factors in the tiominant role of the diaphragm cell in the United States. -1good mercury cell can niake a cell liquor directly from the cixll, containing 50% or higher sodium hj-droside and with a salt content of less than 0.0027,. Cell liquor from diaphr:tgin cells, on thc other h m d , contaiiis from 10 t o 12 waight %: of sodium hydroxitk and more aodiurn chlorid(3 thltn sodium hyt r y to evapor:tre this cLall liquor down to >O7? sodium hydroxide in order t t J c r j llize out tho bulk of the sodium chloride. leaving n t50yosodium hydroxide solution containing aliout 1y, sodium chlorid!, o n ihe liquid bssis. This is called “standard” liquid caustic o r “stwndnrtl electrolytic” cwiiiderd too high for a liquid caustic. The 17, s d t , conte fen- uses. such as the production of o ~ r:tyon, l mil this h.ts led to intensive work in the industry due!? this sodium chloride contcnt, and a150 the much rinal1c.r amount of othcr impurities such as sodium csrhonatc, sodium chlorate, I I C ~ J V V metals, e ~ c . h i o i i g this purification proccs n.hirli h a w h n u v d coniincrcially arc1 the following: Crystallization of sodium hydroxide either as the monohydrnt,e ( S a O H . H 2 0 )or preferably the heptahydrate (SaOH.3.5H20) Sulfate process in which sodium chloride is precipitated as a triple salt (i\;aOH.?r’aCl.?;a2S04) Colunibia’s D-H proces, which involres extraction of sodium (>tilorideby liquid ammonia

In additioii to the removal of sodium chloride, all the elcv:trolytic caustic purification processes. ? l J l i l f ? more and some Icss, require, treatnicbiit for removal of iron aiid chlorate, decolorizing, clarification, and filtering. So-cnlltd “high grade” or “rityon grade“ 50% liquid caustic vvhich is entirely accoptable to the viscose ra>-on industry, can be producei! by a t lesst two of these or modifications thereof, and large tonnzgcs of elecic soda, .si) purified, arc‘ currently being used for this purpo 1)hiit-i iii~istthwefore hsve caustic evaporators and steam generatoi3. If the caustic is requirod t o be of rayon gradt o diaphragm cells. In one C‘anadian nitwury roll plant, :ill Ltttcnipt has been made to overcome this disadvantage h?- rci iimitig tlic: tlcpleted brine after dechlorination to tht. wrll for rwtt iir:+tion i n the underground salt bcd. It has been proposed to operate diaphragni cells a i i c l ii1i.rcwry cells in the same plant, using brine to f v i d Ihe diaplirqyi cc~lls and the rc~covertdsalt from the diaphragm plant as the, f t w l for the mercury cell plant. I n spite of tho apparent n w i t of this scheme, it is not being used on this contiiiciit, as far as is kiioivn. Diaphragm cell plants require substantial quantities of steam for evaporation of the ccll liquor, ahereas mercury cell plants require only a nominal amount,. \There cheap fuel is available, or a h e r e power is generat,ed by steani turbines and bleed-off steam is available, this is not a serious disadvantage. The must marked expansion in chlor alkali pimluction has occurred during recent years in areas (Gulf C u a t , Ohio, and West Virginia) where cheap fuel is availahle, bleeder-turbine steam power is utilized, and salt, is obtainable as brine from wells. These circumstances arc?all favorirhle for diaphragm cplls.

\\‘lieri, t‘uc.1 is t.xpciiaivc but ehtaap hydroc:lclctric ~ ( J w c ~is. sv:rilnblca, tlir dia1)limgin ciLll pror i-; a t :t di.sadvant:igo a i coinpnrcd with the rncrcuiy cc~ll. This situation is probably largely reijponsibli, fur the, c~stt-n;iveinstallation of mercury cclls in C,‘an:tdit. JVhcn rayon caustic is rcquircd, the mcrcury ccsll has an importttnt point, ill its favor bibcause rayon caustic is productxl directly, Tvhereas the diaphragm cclll operator has to spend around .%I per tori of c:tnstic t o purify his diaphragm cell caustic. Jlerrur?. cclls are considered more touchy to op(’ratc, and vnrious problciiis must be met, such as rcmoving tr:tcw of nic’rcury from the hydrogen and from the caustic sotla, avoitling incrcury poisoning of the vorkcrs, and avoiding dmgcrous conwntrtitions uf hydrogen in the chlorine gas. On the otlicl* hand, the use of the sodium-containing amalgam as a reagent, for purposes other than production of caustic offers an inti,rcstirig tool for fine chemical production. Any given situation has to be very carefully studird i l l r~Sp(’rt to these atid many other items to determine tho most econoiiiic:*l choice of ctll. .Uthough in many cases the cells are dircctly coinpetitivr, there are certain combinations of circumstanctxs where one t y p iiiay h:tvc a vcrv signifirant over-all economic advantage. ELECTROLYTIC VERSUS 4\1\.1ONIA-SODA CAUSTIC SOU4

Almost all the raustic soda in the United States is produced h y causticization of soda ash with lime, or electrolysis of sodium chloridr brine n-ith chlorine as a coproduct. I n the first, process, most of t h e soda ash is made by the ammonia-soda or Solvay process, and only a small proportion comes from natural soda ash. The caustic soda made from soda ash is therefore known i n in the trade as “ammonia-soda’’ or “lime-soda” caustic soda, whereas the caustic soda made by the electrolytic process is knova as “electrolytic” caustic soda. It is not possible to vary the ratio of caustic soda t o chlorine in a n electrolytic ccll from the molecular ratio 40.0 to 35.5 or about 1.126 tons of sodium Iiydroside for each ton of chlorine made. Figure 7 shows thc production by years of ammonia-soda and electrolytic cau.itic soda. I n 1937 the production of the elcc-

I K D U S T R I A i A N D E Er' G I N E E R I N G C H E M I S T R Y

October 1943

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~iJ[)llll'UtS 2Ll'i: ht,!L!d b

'li)\V.

1niprPgii;itio;i 11i gr;ip?iitc :itio 11,s to give l o n g x ariollc life ; i i t i l l o w r gr:ij!liit P c o i i ~ m i c~r n). ~ Chiiver.ilr1i fi,oiii r i i v II-P trt' 1~1t~:tchiiiy pontler t? liqiiiil chloriiir for pulp Irlwchiiig. I di:tpIii~:tgm tvpe of cell, :imi grc..it L)evelupnic:it of t h e df:po incre:isr 111 i t L :impere c a p Sireai ini!rt.ii\.enierit in t h rizoritxl nic~rn.iit.yrell, and inc*rL i n its aiii111~1~1~ vxpacity. P:irti:il tl~:~.c~lopmeiit of the v c r t i i d ri,ixtitig niercury 1 . ~ ~ 1i 1n Gc~rnlan\ i riiiicah I ( w floor sptcc than the horizont:il I n i ' r i ~ i i r ? cell). I-vof 11ir1;t.l equipmctit in e11 dv~-eIopnirntnf t h e fori,f!sicir Cviipor'rt O h .

Developmelit of thtb higli prcrsure stesru boiler atid t h e 1 ) l ~ t d e i ~ turbine grneration of po\ver and exhamt stc:ini arid it-: use iii supplyiny pon-er for electrolytic chlorine plants. .(Irate process for purifj-ing electrol! lium cliloride reduction 1. Co1unibi:c's liquid ammonia process f i ~ rv r luring t h e zwlium chloride content of rkctrolytic caustic. llercury >trr rectifiers, a great iinprovemerir over rotnr,y ~011vertcrs n n i l niotiir p i c i n t o r sets f11r conversion of :illertintiilg i o direct c u t w i i t pon-er, particularly wlicrc the cirruit voltage is in the .iOO- I o 800-volt r:iiigt'. vhich is iimv fust bwoniing st:ind:I i ~ dp l ' n (.t IC('.

(;w:it

iiiii~t,,i~.[~iiit,Iii~ in brine production and purification,

iiiclutiiiig utilization of carbon dioxide from stack gases, use of

DEVELOP3IEhTS I N T H E CHLOH 4 L K A L I I.\DCSTRT

cheniical, cheniical, and chemical eiigicscwch n.i)rk has bwii done by the chlor alkali industry during its niorc than 50 years of csieicncc. This iiltensive work has brought about a great many iniprovcincnts which havv tended to lon-~rinvc,stnient and opi,rating costs (c>srty)tfor inflation), iinprovcd the quality of the products, and f i j f \ - of tisritiling anti distriI)iitiiig r 1 1 : ~ .

"

c~l:iii-Hort.iil:it~~r~ and clarifiers, and s a ~ i dor other type of per( ~ 1 1 : ti ion tilt flr3, 17:iriou5 methods for the purification of liquid and gaseotls i~liloriiii!. Iinproveriients iii chlorine cooling, drying, c~oiiiprc~siiig, itlid lirluefactiori. Packaging and transportation dewlopnientj, iricluding multiunit cars and single-unit cars up t o 55 tons' capacity and mo,ct recently barges equipped with four 150-t,on tanks. Development of evaporators heated with Dowtherm to r'arrv caustic evaporation from 50% or higher up to fusion instead oi using direct-fired pots. Looking iiito the future, i t ir not increditable that diapliragin cells will be developcd which n d l effect a !iigher percentage decomposition of the sodiiiiii chloride f d to thc cell, prriniiting :i niiich highrr conccritra t iw n i so~liiiniliytiroxirlc in the, cathode

1921 1923 1925 1927 1929 1931 1933 1935 1937 1940 1942 1944 1946 1947 1948

Figure 7.

Production of Ammonia-Soda and Electrolytic Caustic Soda in the United States From U. S. Census of Manufactures and Chem. M e t . Enp. estimates

2164

INDUSTRIAL AND ENGINEERING CHEMISTRY

liquor, and possibly w e n Rayon grade caustic soda directly from the cells. It is certain t h a t cells will be developed having higher and higher amperage ratings. -4 vertical mercury cell vary economical of floor space is a possibility. Contact or mechanical rectifiers capable of high efficiency eYen at, lorn voltages, which were in limited use in Germany during the war, are now being made in this country and should have a widespread use. The economic recovery of chlorine from by-product hydrochloric acid by an improved and modernized Deacon process is a definite necessity, and entirely within the realm of possibility. Rrsearch has had a poxerful influence on the chlor alkali industry. I n addition to the technological developments referred to above, the developnient of chlorine derivatives has played a most important part in the gro-rth of the electrolytic alkali industry. Such tremendously important developments as the chlorinated organic compounds put on the market by Dow, Carbide and Carbon Chemicals, D u Pont, and others, have bern the cause of the phenomenal growth of the chlor alksli industry. Seven raw materials n-hich are combined with chloririe xrourit for a great deal of this growth. Ethylene, acetylene, hcnzene, i olume. methane, ethyl alcohol, and naphthalene are among th: important raw materials which use u p the bulk of the chlorine n-hich goes into chlorinated organics. A great deal of excellent sales development, work has also been done on developing uses for these organic chlorine compounds.

ACKNOWLEDGMENT

The writer thanks the following for help given in the preparation of this pap’r: 9. G. Osbornp, If.S.Kircher, D. L. Taylor, D. S. Rosenberg, and c‘. K. Lansing of the Hooker Electrochemical Company, and R. T . BaldKin of the Chlorine Institute. BlBLIOGRAPHY

.liion.. Chem. IndS., 63, 371 (1948). Anon., Chem. Met. Eng., 49, S o . 12, 114 (1942). I b i d . , 51, No.& 115 (1914). Ibid., 53, No. 1, 113 (1946). Barton, C. I t . . Trans. Am. Inst. Chem. Engrs., 13, 1 (1920). Brallier, P. S., Chem. X e t . Eng., 28, 846 (1923). Brallier, P. S., Trans. Electrochem. Soc., 86, 76 (1914).

Chlorine Institute, “Bibliographic Notes on Chlorine Cells and Related Matters,” private communication, Feb. 21,1940 (extensive). Cnglehardt, V., “Ilandbuch der technischer Elektrocheinie,” Vol. 11, pp. 1-95, Leipzig, Akndemische Verlagsgesellschsft, 1933.

Gardiner, W.C., Chem. En:)., 54, S o . 1, 100 (1947). Gardiner. W.C., Chem. Met. Eng., 52, N o . 7, 110 (1945). Hightower, J. V., Chem. End.. 55, No. 12, 112 (1945). Hooker, A. H., Tranr. A m . Electrochem. Soc., 34, 149 (1918). Hooker,A. H., Trans. Am. I n s t . Chem. Engrs., 13, 61 (1920). Hou, Te-Pang, “Manufacture of Soda,” AM.CHEJI.Soc. Monograph, New York, Reinhold Publishing Corp., 1942. Hunter, R. hl.. Chem. M e t . Eng., 52, No. 10, 104 (1915). I. G. Farbenindutrie, U. 3. Dept. Commerce, “Reports of Chlorine hIanufacturing Commission,” PB 20844. Ibid., PB 20851. Johnstone, H.F., Chern. Eng. Progrcd.9, 44, 657-68 (1948). Kircher, M . S., and Hubhard, D. O., Elec. Eng., 66, 1059-63

GERXlAK CHLORINE INDUSTRY

Just before and after the close of the war with Germany, riiaiiy technical investigators were sent over t o study their technical developments and progress, including about a dozen men selected from the United States chlor alkali industry. A great many very interesting reports 7%-erewritten by these men on German chlor alkali progress and developments, and a tremendous amount of information F a s uncovered in the files of the German chemical plants. Much of this was brought back t o the United States or covered in reports. By arrangement with the Chlorine Institute, about 1900 pages of scientific reports on the Gcrmnn chlor alkali industry, called the “Chlor Fako Reports,” w x e translated and distributed t o subscribers in the United States. ,411 these reports constitute a very real addition to chlor alkali technology.

(1947).

Kirkpatrick, 3. D . , Chem. M e t . Eng., 35, 158 (19%). Kokatnur, V. R., Trans. Am. Electrochem. Soc., 34, 1-55 (1918). Laniie, I