PRODUCTION OF IRON-FREE ALUM E D W S -4. GEE C-. S. Bureau of Mines, FPashirigtori. D . C .
A 2-ton-per-day continuous pilot plant has deriioustraretl conclusitely the chemical arid mechanical feasibili t > of a process for iron-free alum production. Under optiriluni conditions of operation, an alcohol loss of O.*3y' is realized. I he estimated production cost of S39.91 per ton of alum in a commercial 20-ton-per-day plant indicates that, uuder present marLet conditions, the process would not be e r o nomirally feasible. The basic significance of the prove-5 lies in the fact that an expensire organic chemical Cali, b g proper engineering design, be utilized to produce a \erg cheap inorganic tonnage product. If a material w i h a higher cost differential between crude and finished product than alum were purified, the process w o u l d u t i doubtedly be economically sound.
-.
T
0 NEET the grolving demand during World \Tar 11 iirr iron-free alum, used primarily in the production of .qyrithc.ric, gems, gasoline cracking catalysts, fine chemicals, and wrtxiii military applications, and t o stop the diversion of stratcyic, aluminum trihydrate for t,his purpose, t h e . Bureau of 31iil(developed and evaluated a novel process for the production ( ~ i ' alum directly from domestic raw materials of unrestricted supply. T h e Bayer process for the manufacture of aluminum trihj-dratt b is the only method t h a t has achieved industrial application or commercial significance in this country. Ailthough the p1uduction of aluminum met,al has created the major outlet iirr alumina, this material \vas in great demand during t,he war a" a base for the manufacture of certain strategic and critical aluiiiinum salts, such a s iron-free alum. IAJKgrade bauxite and clay are inore amenable to ;tcid tlxtraction than t o alkaline treatment; but the aluminurn sdt r: resulting from a n acid leach are alivays contaminated with, and heretofore difficult to separate from, iron salts. -4ny acid prorw s for the production of alumina is thus confronted \\.it11 thc, problem of first separating the iron and aluminum salts foriiicil during estraction of the ore. When sulfuric acid i,s used, thc resulting salts are sulfates; therefore a n effective purification procedure will provide a source of iron-free alum iiidepcndent of the Bayer process. High silica bauxite and clay remained unrestricted during the national emergency, and although such material can be procc in a Bayer plant,, the consumption of soda and loss of alurnina make production expensive. A successful acid process for manufacturing iron-free alum must, as a minimum objective, achieve a n economy t h a t will compare favorably Jyith the alternative of using a premium-priced aluminum trihydrate made from low grade bauxite. 1175
T h e wparation of two water-soluble salts can frequently be d by introducing to the system a n organic solvent in which he salts is insoluble and thus effects selective rcmoval of t!iat component. The fact t h a t aluminum sulfate can be precipitated from its aqueous solution b y the addition of ethyl alcohol has long been recognized, and the marked solubility of fcrric *illfate in this same organic solvent is well established. S'ittorf \vas apparcxntly the first t o propose the application of this phe~ i o ~ n c i i oas r i a practical method for the purification of crude alum st)lutions (6). Patents covering the use of alcohol to purify aliiniinum sulfate have been issued in England, France, Switzerland, and Belgium, although the first three presumably covw the same procedure (2). Roller ( 3 , 4 )has conducted considerable experimentation on the i'undnmental considerations of the problem, and brought to the at tcritioii of the Chemical Engineering Section of the Bureau of JIincs a floiv diagram utilizing elevated temperatures, the advantage being a substantial reduction in the quantity of alcohol rtyuircd. LAl3OR.ITOKY STUDIES ,111
cixhtiustive series of laboratory tests demonstrated that,
ivit hin practical process limits of temperature and concentration,
the alcoh01 does not enter into chemical combination with other c~oinponi~nts of the system, nor does any appreciable amount of thc. solvent decompose. A theoretical approach t o the prohlem of loping a process therefore resolved itself primarily into a study of solubility and phase relations. Tile wolubility of alurninwn sulfate in aqueous solutions was dt.termincd and plotted as shown in Figure 1. Although thc concentration of dissolved salt is a t a minimum when the solvent contains approximately 81% alcohol, i t was apparent from t h e change i n slope of the curve t h a t a n ultimate process concentr:ttioii of 50 to 55% alcohol would favor the use of less alcohol without appreciable sacrifice in yield of product. As the inwluhiliiy of :tluminum sulfate in alcohol solutions is significant only as contrasted with the solubility of iron sulfates, these d a t a \\.ere determined and are also plotted in Figure 1. To preverLt hydrolysis of iron salts, a small quantity of free sulfuric acid was added r,o the solutions. It is apparent t h a t both ferrous and ferric sulfates are consider~ b l ymore soluble in alcohol solutions than is aluminum sulfate. Crude alum normally does not have an Fe?O!:Ai120,! ratio grcater thitn 0.04; on this basis, if precipitation with alcohol is effwtcd from a sat,urated solution, the residual solvent mother liquor will be greatly undersaturated with reapect to iron sulfniw. Sirnplc mixing of alum arid alcohol solutions, however, was found t o result in precipitation ot' a product from which on!y
September 1947
1179
INDUSTRIAL AND ENGINEERING CHEMISTRY
about 90% of the iron had been extracted. If the crude alum contailis Fe203equivalent t o 37, of the .11?O.icontent, it is IICCWsary to extract 97 t o 987, of the iron in order that the produrr may meet specifications for iron-free alum. Extensive lahoratol,>stutlics were conducted t o develop processing details that n-oulci rake the efficiency of extraction from 90 t o 987,. Quality specifications for iron-free alum depeiid upon the p u ~ ' chaser's requirements. One large consumer has reported thut. liefore the national emergency, material made from high gradr trihydrate had to conform t o the following anal proximately 17.007,; FenOa,not t o exceed 0.003%; S a 2 0 , not t o esct~!d0.15%. An inferior b u t apparently acceptable gradrioi product. equivalent Fe20:, no distinction i2. I n the range 0.1 t o 5,0co apparent between extraction of ferrous and ferric iron. an avri'ayc. iron removal of 97-98?c being easily obtained. 3. Product yields of 93 t o 9 7 5 are realized.
Figure 2.
2
.-
B
60
-5
B-FeSO4
\
ti
V
A-AIz(S04)s
sc
C - F e z (504)~
0 u1
E
g
4c
g 5 -g 0
3c
6 2c
I(
(
10
20
30
40
50
60
70
80
90
100
E t OH,Weight percent
Figure 1. Solubility of Ferric, Ferrou.. and tlitmirluiit Siilfatri i n Ethanol-R-ater Solutions at : 1 3 O C. (1.77~Frer Sulfuric Acid)
4. T h e alum hydrate precipitatcti
is
unit'otmly t h c s hcxzadrca
salt at room temperature.
5 , T h e coninion industrial denaturant, formula 213. may be substituted for I-,S.P.alcohol, and t h r procws ran thus URC a t a r t ' i , c ~ l wlvc,nt.
South Elevation of Small Scale Pilot Plant
INDUSTRIAL AND ENGINEERING CHEMISTRY
1180
Vol. 39, No. 9
Duriron
H
SECOND F L O O R P L A N Figure 3 .
Ground Floor and Second Floor Plans of Equipment La?out i n (:ontinuousPilot Plant
T u o lead-lined'jacketed dissolution tankb f o r aluiil. rnrti OS 4 . i O - g : i l l ~ ~ t ~ c a p a c i t y , with s t e a m coils a n d paddle agitators Twelve-inch Shriver piate-and-frame filter pre\s Single. lead-lined, jacketed evaporator, provided with !-inch 1e;id cull: 3 for vriniarv h e a t transfer: 18-inch flue a t t a c h e d for v a D o r exlinikt 4 . A l u n i s t o r a g 6 t a n k . Identical in construction t o e r n p o r a t o r except for s t e a m coils a n d sight glar,es; both i t e m s of 530-galioli capacity 5 Lead-lined 840-gallon alcohol storage t a n k 6 Ratch crystallizer (this unit did not figure i i i continuous uperntion! 8 Lead-lined 910-gallon slurry storage t a n k provided with tuw Inrre paddle a g i t a t o r s dtninless-steel 28-iiich Biid solid-bua.1 continuous rentrifupul t, 11. F i l t r a t e s t o r a g e t a n k (identical to i t e m 5 ) 15. Thirteen-plate, bubble-cap fractionating colunin. fabricated 0 1 -i:iiiile... iteel Copper condenser (6 feet X 1G inche-) f o r \-nporb from c u l u n i i i 17 18 Primary alcrihol receiving t a n k s , of copper cvnstruction a n d l ? ~ - g : i l 1 < J r i capacity 1.
2
\lcotii!l bleiidinv, t a n h , idelltical tu item 5 with s i d e - e n t e r i w proprller agitator I.:ighty-aalluii lead-lined, jnr,keted mixer, equipped u-it11 .teaim ( UIIP a n d turbine agiratur 21 Half-inch lead heating coil, 45 feet i n length, imliiersed i i i a d r i i i water provided with > t e a m inlet as a heat source 2 2 . Four 25-gallon c r y s t a l h e r s fabricated of stainless steel, u i t t i coils a n d turbine agitators 2.j T n o duplicate lead-lined alurii >till.\ of approxirnately 23fJ gtillonw r a p a c i t y , jacketed, provided u i t h h e a t coil- a n d large p:iddlr :ieitator5 a.ith \upplenientarv baffles 2li. iiiiall copper water-cooled condensers, 3 feet X G incheb tee1 screw c o n i e y e r for wet cake 2 8 . Conatant-heat lead feed t a n k s of approximately 6 galliiiii ~ U I J : I < ' I I > 29 Twc supplementary lead-lined alruhol storage units, of approximotel?, 300 gallons capacity each 'l'he rectangular blocks represent 1- and ala-inrh centrifugal pnriil,. with rlie inaterial of ronitrricrion printed f o r ench
!9
20
INDUSTRIAL AND ENGINEERING CHEMISTRY
September 1947
1181
1 , l'ilut plant iroil-c'iti,ac.tiiiti ~ ~ f f i r i ~ ~ iavcsrage i r i w 07.8';.
2 . .in average alum yicsld 1 1 1 !)4.6' , \vas :itrained 3 So unusual mechaniciil l i i ~ o l l lthni* ivvre encountered. 4 of thc alloys testrtl t o nirt't T tie abrasive ctiaracteristics of tlit, tal >liirry, stainless steel ai)pcwwi to be the mort, satiefacTory, except \\-here concentratrtl aluni solutions were concerned. 5 . Lead was an acccptabk material for all stationary equipnirnl a n d piping requirements. 6. Based on higher recoveriv;. c)f solvent, simplicity of equipment, and superior heat traiisfcxi characteristics, distillation drying was selected as t h e beat systeiii for recovery of the \vash alcohol. 7. A s expected, the over-all lo-.. ( i f alcohol in this unit \vas extremely high, amounting to 0.05 gallon of 10OC; ethanol per pouiid of product. 3. .is it was inipossiibli. t o i ~ l a t e thP foregoing figurc t o performance t h a t could br ailticioated in a TI ell designed. totall\ vnclnwd plant! :i larger inatallation \vas a virtual necessity i n r r~\~:rluating this factor nlonr~. (;O\TI\CTQC.S
l l i l e r . Heating Coil. atid (:r>+talliver* (Items 20. 21. and 22 of Figure 3 )
P I LWL' l ' l , t \ ' i '
The foregoing laboratory and atmipilot p h i -tudic,- ~ I V I I I I I I I .-irateit the chemical feasibility of the process, but the operation. \vew i i o t on a scale large enough t o permit a reliatjle evaluation oi m s t . -1s stated before, thr critical variahlc. that could I K O ~ I W t i \ t ~ l \va: alcohol recovery, which iitiviou.ly ront roilrri tlic'. ininicrcial posyihilitirs of thts developnirmt . The continuous pilot plant \\-as 1oc:ited in the Collegt. Pai,li I,:xpcariiiic>ntStation of the Bureau of Mines \\-hvre 3700 squarr, ttvtt of flo(Jr space equally distrihuted betnt,en tn.o flooi,s ~ v a :tllocated to tlie project. Plant dwign \vas based on tllr fort.gt)ing t\vo *cctions. and Figure 3 slio\vs 1oca;ttioii of v:triou,s itrni-. ~ ' R o c E ~ ~T. h e initial concpption of the continuou.: prooes; iillustrated by Figure 1 which * h o w thf. floir of niateiials kxisctl O I I pi,iniary process pipiiig. The raw material for tlie process \vas crude xluili wiitainiiiK varying percentages of iron a n d ineolubles a; ~ h r ,piincipal iriipurities. The alum, as reccived in 100-pound papcr sacks, \ ~ H C (-hai,gedto the dissolution tanks by nieans of chute and hoppc>i' friini the second floor. Sufficient alum \vas ciisso1vc.d in hot ivatr'r to produce the desired specific gravity, and the solutioi~ was acidified by the addition of concentrated sulfuric acid intiwluced through a lead funnel via the chute. Insolubles present i n the solution were removed in the Shrivrr filter press, a n d the i.l:trifird liquor \\-as pumped t o the evaporator. \vhcrc' t h c k final :ulju~tnientof concentration (varying from spwific. gi,avity 1.20 t o I ,14) \vas made. T h e adjusted alum i o l u t i o n \\-as t t i t l i l punipcd to the alum storage tank, froin which i t \\-asiiietiii,ia(i through a rotameter a t any desired rate and niiicd with a i n ' t c ~ i ~ cstrrain d of alcohol in the mixing tank a t about 60" C', witti the iniinrdiate forniat,ion of a sIurr?- of impure alum By nieans of the coil heat eschanger the temperature was raiuetl to the invariant point and the requisite three-phase sy:-tern wac attained, temperature varying from 68" to 78" C.! depending upon initial conditions. Cooling and concoinitant crystallization \ver, \ \ - l i c w arlheriiig alcoholic wash liquor i v a ~distilltd nff. 1Ioltt.n alum from this operation \\-as porirc'ti into i i . o i i p i 1 1 5 for solitlifcatioii arid packaging. EQLIP~IEST \ I ~ I ) I F I C . ~ T IIn O Sviciv , ot t htl liniit ( s i 1 i l i ~ s i g i data and operatirig caxperic.nc.e that could t i c gathc'i,id l'iwni the l ) i i t ( * l i pilot pl:tnt, it \\-as anticipated that riintinuou$ unit might deinonstratcl t h c n vt'r, thi? n-ai I i n t thil cast and slight adjustments, the tiasic. : i r r : i r i ~ c ~ i i i c n t not altrrcd dui,irig the entire d(~vr1opnic~iit study. .imajor difficulty arow in the rnetering of :,lurry. It h:id t i w i i Iilanned originally t o niaintairi a c(JIiSti11lt lcvcl of 4ui.r~.i i i t he iiliim-alcohol mixing tank hy automatic instrunientatiiin nctuitting a cciitrit'uyal punip. Frequtxrit plugging oi thi. t~llxi\rs yew l t r d from interiiiittc'nt pump operation, a n d n i n i i r i : t l control ' T h i s p:~ot)l~~ni i i i flow was attcfiniptcd with little iinpivveilicynt. \vas nirely solvcd hy the use of a si& ovi~rHo\vn i l t I i ( s niixiiig t:ink, irtierehy tht. slurrj- \\-a; indii,isc-rly i n r ~ t i ~ : ~ t . r 1)). I t l l c , iiic~iiniiiig *trrania i ) t alum ant1 al(wlio1. .4 siniiiar p r o l ~ l ~ ~rrwlterl ni iii attcniptc:d nietc,riiig of
IiOt
H2O
Fe,(SO,),
STORAGE AI,(SO& Fe,(SO,), HaSO, H*0
2420.7 22.4.
INSOLUBLE 62 AI,O,(EXOESS) 28.9 Ha0 I 7 95.6 4773a
I pH
-
f ADJUSTMENT
2 5 17.6 22.4 74.0 12628.6 15242.6 t
TO ATMOS-
~CRYSTL A LIZAT Io N
c:iuscYi
I
5266.0 7880.0,
WET CAKE AIz(SOo)3 Fe, ( S0,) EtOH H2O
Al,(§O,),
r
1 WASH ALCOHOL 4720.0 31 60.0 -__ 7880.0
1
2517.
MAKE UR WASH
6413.0 8283.9 17310.9
1 1
2301. I 0.6 1559.7 2979.46840.8,
6.2-T0 WASTE
INSOLUBLE
163.8
opcr:itiiig esip,n(,i(,., 1'iFur.c 5 i. t i ni:iicri:il tul-
1503.6 1559.2
/MAKE ue P R O C E S ~
F ILT RAT ION
710.9
[H,O
, I I. ,
To GRINDING
9573.3 8464.5
'
~;i~dgu::,l
RESIDUE 1698.3
4000 .O EtOH
*CUMULATIVE A LC 0 H 0 L LOSS SHOWN I N S T I L L RESIDUE.
* 5 7 82.2 6 150.1 ~-
Figure 5 .
x
1 foot drum \vas blocked off for
UNIT OPERATIOX S
,Ilthough any iIltiUstI'id appliestiori oi an alcohol process for producing irod-free a l u y undoubtedly would be located in a commercial plant producing crude alum, the pilot plant necessarily included farilities for dissolving and concentrating dry ground alum as supplied to t'he market. Aiter dissolution in acidified aqueous solution, the crude alum solution vas filtered in a S h i v e r plate-and-frame p r c ~ d ,using canvas cloth. Concentration in a steam-heated evaporator preparatory to storage or use was coiitrolld hy spccific gravity and p H nieasurcint~nts. An opwating schr~tiule Fur this unit t'ollmvs: C R I - U E .kLU\f
1
10811.2
CRUDE ALUM Al,(SOJ,
+
FILTR AT ION
DILUTION
I!.
opt iiiiuni conditions 01' opcr:iiiuii, Capacin-. Origirially dcsigncd for w production of 2 tons of alum per 24-hour day, the plant proved quite tic~zibl~~, and satisl'iictory operating liLt('> of 1 t o 2.5 tons per day were ii c h i e v ti. A 11 equipment proved to be of sufficient sin, and flesibility t o opcbrate a d e quately over this range, Lvith the exception of the Bird c n t r if u g a l . This unit did not provide satisfactory washing efficiencies at the higher rates. T h e Goslin-Birniingham rotary varuum filter was oversize a t the lon-er r a t e , a n d a portion of the 3 contiuuous operation.
1183
A&DJCST3fEST.
AIaterial Balance in Pounds per Day
Charge. 635 gallons of Solution at specific gravity 1.1!16 (25" '2.); alum content 1000 pounds at 17% .Al?Oa,I-I,SO, contclr~t35.7 pounds. Evaporatiari Time, Hours 0 1
2 3
+
: k
Protiicct. (800 : 16H.O. ( 3 , )
s p . GI. ;80' C I
ire;iru ('i,rlden.;are.
1,b.
,..
1'iiq I . 1s4 1 217 1.252 1 280 1 316 1,378
ti48 Y3ti 132.1 !(io2 1862 2100 232.3
'
155 gallons of solution at specific gravity 1.378 1000 pounds at 17"; .ilYo3 = .%I~(SO,I~.
I N E E R I N G CHEMISTRY
V O l . 39, No. 9
ac,iil-frec solution of aluniinum sulfate, and the pTI 3.11 empirical relation, the 11
t o iin
ic.rmiiic,ti. By mean,- oi such C r u d e alum a d j u s t rnent
-
Fiitralioi! (Bird rentrifiiga!)
Filtratioti (Goslin-Birrningham filter)
hlurn analysis Alum charged W a t e r charged HrSOa charged Alum specihc gravity Free acid
Cheniirnl ITeighr E'loamerer .\Ieasureiiieiii Hydroriierer p H meter
Alurri feed rate Alcohol feed r a t e .ilcohol concn
4 t h cooler temp. Slurry temp. Filtrate temp. S l a s h rate Current consumption Filtrate r o l . Filtrate concn. Wash-liquor retention
Rota meter Rotameter Ilydrumerer Thermometer 'Thermonieter 'rher monier e r Thernionieter Thernionieter T1iernionie:er Thermonirter Thernionir: er Rotameter .Inrmeter Gage g l a , ~ ' Dihrillatirrii Evapuratiolt
30
Slurry temp. Filtrate temp. Drum meed
Thermonieter Thermomerer Stov watch
I.? I i j i i i . 1.5 iiiiii. 0nadiii.b
K a s h rate Vacuum Hood pressure Blow pressure, cake discharge Vapor temp. Condenser temp. Filtrate vol. Filtrate concn. \Vash-liquor retention
Rotameter Gage Gage
1i 13 15
8 8 8 8 30 30
hr lir 11r hr IIIIII ti1111
13 i i i i i i 13 riiiti 1; n i i t i 13 I I I I I I 1 lir 1 Iir
IS O F
A
~
The alcohol content, of various m i l ~
~
~
~
liii'i
;\llCC' III'
]J~~Il~IllC'~l'l'.
lllFlit
Dryirir
Disnllanon
(-sing these aiial!,tical techniques with reference t:ihlei :tud 1,li:irts prepared for the various unit operations, there T ~ R Sno lag in data report.. Plant technicians made all determiiiatimiGage 1 3 iiii~t, ThermunietPr 1 lir. iwriconiitant with operational duties, and satisfactor!. reiult 8 Therrnoriieter 1 hr. \V l ~ ~ . \ ~nct or sulixrquerit operational detail-. ti1111 II!III
tliiii.
1
USIT
Crude-alum a d j u s t m e n t Crysrallization Filtration Drying
R a w alum Alum feed Slurrv to filter Cake"from filter Filtrate Discharged alurii
3 hr. 1 hr.
7
--
S o special problenis were encsountered in cit1ic.r collt~c~rioii IJf d a t a or sampling. For purposes of pilot plant control, . analytical control expedients n-ere adopted to facilit:ttcx cipt~rations. O F ALTXISL-M ST;I,F.~TE SoLrmoss.. Iroii XA. tic.tc,rinincd in t,he crude alum solution by titration n-ith 0.23 .\' potassium clichroniate. Iliplienylamirie v a s usod a b iiitlicBaroi, after total rcductioii of the iron with stannous chloi,itle: c\c the latter n-as destroytd i?-ithmercuric chloride. Aluiiiiria \vas dettarniined in the crude alum l i q u o ~1))- gi.:iYiiiietr,ic precipitation of e R2Oa with arnriioniuni hyclrositlt~.1.ing liromocresol purple indicator. T h e aluiiiina v:i,. t t w i i el[,terniiric.d by difference, ing thv iron value obtained ahorc,. FOI, rapid pilot p l m t control this mt,thod %-casunsatisfactory: therc3fore, specific gravit,y or density \va> employrd in the pilot plalit. Talilcl IT'- gives d a t a on tticae c*oiistants, Ivhich agree iri ge11 w i t h those previously reported ( 5 ) . The boiling points prov a n iidtlitional index of alumina concentration and n.cre of si) value\ in t h e drying operation. (kmsiderable difficulty [vas espericnced in dcteriiiiiiiiig E i c v acid. The standard potassium fluoride t,itratioii is di consuming, and not applicable to pilot plant operation inize lag in obtaining control data, coneid(~iablcStud, and a novel procedure \vas developed in which pII of d i l u t d :ilw minum sulfate solutions (specific gravity 1.18) \veri% plot t c d against concentrat~ioriof sulfuric acid per 100 grams of aluniina. D a t a were obt'ained by adding known quantities of mlf'uric iwid
-
...
I ___I__
5
10
GPAVS
15
HZ5C4 PER
20 25 100 G R A M S AI,O,
I 30
Figure 7 . Calibration Curie for pH 3Ieniuremenf* of iluminuni Sulfate Solutions (Specific Graiity 1.1X,Z.i" ( .) G
pir
151.01
100 c. I14
PH
c,
I1
100 G
\o $ 1 9 0
0
1 57 1 38
10 13
1 17 1 06 0 %
1ci 0
,
20 0 30 0
~
~
Cr1ni.n , Grains .AI,O3/100 311.
Pp. G r . (90C/40 C.'
Density
(100' C.)
1 33 1 40 1 43
1.?I
IC, 17 18
1 46 1 48
Boiling Point.
c.
102 104 106 106 107 10i
1.20 1 32 1.39 1.42 1.45 1,47
1 2i
10 12
1187
INDUSTRIAL AND ENGINEERING CHEMISTRY
September 1947
4 0 0 6
2 8
EYALG.ATIOY OF PROCESS
T h v primary objective of the pilot plant development was t o evaluittc this process 11-ith respect t,o potential commercial ap-
plic.atiori. The preceding discussion of pilot plant data is conf i i i c d larg111y t o mechanical operation and quality of product, ot)t:tincd. Khile thege studies n-ere being conducted, the optiilium opclrating conditions were being establi;hed, a n d on this ti:isi3 the material-balance f l o ~ chart (Figure 5) n-as prepared. Data arid Iiasis for calculation of t,he balaiicc are as follon-s: Product: 2000 lb. .A12(S04~3.14H20; 0.0355 F e s 0 3J-ALO~. ('rude alum: sp. gr. 1.37 a t 100" C.: l . l B c C Fe20aiAk1?03: pII = 1.0 (21 lb. H2S0,/100 Ib. . 1 1 2 0 3 ) ; 352 gal. of solution; 2200 lb. AL(SOI\x.l4H?O= 2360 lb. AI?(S04)3.16H20. Alum yield: 90'; recoverv (from plant experience). Procc;s alcohol: 6 8 5 bf wt. (sp. gr. 0.868); 660 gal. ([rom catiar t 1.88 gal. gal alum). \ l a & alcohol: 6 0 5 by n t . ; 550 gal. (from filter data, 0.25 gal It]. caLe). \I ct cahe: 35 1 reduction ratio (40 1 in cr?stallization'i: 97 3rp nashing cfficiencv: 3.57 n-ash-liquor retention. 90Yc product T i(lIi1. D r v cake (product): 2000 Ib. AI2(804)3 14H2O. Filtiate: appros. 54,2Y0 EtOH by w t , ; sp. gr. 0 809, appiox. 1225 gal. Distillation: 8680 gal. distillate; 78cc E t O H by w t . : ap. gr. 0.844 (plant practice); steam consumption 4900 lb. (froni plant 1'1111 251 (0.875 lb/lb. C'2HjOH fed). I b i d u e : appros. 0.585 acid.
n.ould lie con
