CHEMICAL
s. M E T A L L U R G I C A L
ENGINEERING
v o l u m e 4 0 Es t a b l i s h e d 1902 n u m b e r 7 M C G R A W - H l L L P U B L IS H IN G C O M P A N Y , |N C .
S. D. K IR K P A TR IC K , Editor
JULY, 1933
PROBLEMS AHEAD OF PROFITS
S O M U C H O F T H E p erm anence of busi
ness recovery depends on the balancing o f so m an y d ifferen t variables th a t in d u stry can well affo rd to m ix an elem ent of caution w ith its en th u siasm fo r th e p ro g ress of the last few m onths. I t is tru e th a t in no com parable period in the h isto ry o f th e c o u n try has th ere been such a rap id rise in the volum e o f business.
Y e t do w e know ex actly w h y ? U ndoubtedly, m uch o f this business has been placed purely in an ticipation o f price advances th a t now seem certain . F irm s are laying in six m o n th s’ re q u irem en ts and d em anding th re e w eeks’ deliv
ery. H o w m uch of these goods is going into actual co n su m p tio n ? W ill this new business collapse once in v en to ries a re built u p ? N ot, we feel, if all in d u stry m oves fo rw a rd to g eth er an d th e re is no d isru p tin g of the p resen t fa v o r
able balance o f econom ic forces.
T h e relatio n o f p ro d u ctio n an d consum ption is only a p a rt o f th e p ro b le m ; m e re im p o rtan t is the balancing o f w ages an d prices which, of course, determ in es m ass p u rch asin g pow er.
T h is balance is the one th a t now gives m ost concern to th e a d m in istratio n in W ash in g to n . T h e im m ediate problem is to p u t m ore m oney into th e pockets o f m ore w orkers. F o r its own good, in d u stry m ust pay th is p resen t price for prospective profits. I t m u st realize th at, fo r the m om ent, th e natio n al recovery act will im pose a ta x on p ro d u ctio n , designed to get things started .
T h e re is a n o th e r angle, too, to the balancing o f econom ic and in d u strial relatio n s which
some of us m ay have overlooked. I t is the relation of one p a rt to th e w hole of the in d u s
trial stru ctu re. A s w e see it, each in d u stry m ust conduct its business and plan its fu tu re so as to help p reserve th e econom ic balance o f the whole. A n y g ro u p th a t fails to play its p a rt is certain to be penalized.
T h e cotton textile in d u stry has clearly blazed the trail ahead. I t has show n how diverse sub
divisions o f an in d u stry can be closely allied in a com m on purpose. T h e chem ical in d u stries have a com parable o p p o rtu n ity to set u p an acceptable code of practice, b rin g in g all e x ist
ing chemical associations into alliance in a central chem ical o rganization in w hich none will lose its p resen t identity. I n m o st of th e o ther process in d u stries th ere are stro n g tra d e asso
ciations o r independent g ro u p s th a t can be affiliated fo r th is purpose. In fact m an y are already well advanced in this w ork. M a n u fa c tu re rs o f chemical engineering equipm ent an d sim ilar so-called capital goods face a m ore difficult task because of the specialized ch arac
te r of th eir production. Som e presum ably will ally them selves w ith the m achinery g ro u p s being organized in the electrical an d m echan
ical fields. O th e rs m ay w ish to fo rm th e ir ow n association o r revive th e now inactive C hem ical E q u ip m en t A ssociation an d so become affiliated as a u n it w ith the m aster association.
T h e im perative need is fo r cooperative action.
T h e safe road back to u ltim ate profit lies squarely in th a t direction b u t th e re a re still m any problem s along th e w ay.
E D I T O R I A L S
A Good Start On a Bad Problem
I
N S T R I K I N G c o n tra st to the feverish, im pulsive activity of th e N IR A , is the cool, deliberate planning of th e T ennessee V alley A u th o rity . B o th agencies fa ith fu lly reflect the tem peram ent o f the m en a t th e ir heads. T h e one is the soldier, w ho has spotted his objective, has his enem y on th e ru n , an d is quick to p ress on fo r every advantage in the p u rsu it. T h e o th er is the engineer, faced w ith a com plicated problem , g ra d ually accum ulating his facts an d scientific d a ta in o rd er to lay out in b lu ep rin t fo rm a carefu l an d logical p ro cedure. D r. M o rg an realizes th a t the ta sk of th e T V A is n o t a p a rt of the em ergency p ro g ram . Speed, in itself, is n o t essential. M ore im p o rta n t in building fo r such a g re a t social ex p erim en t is to m ake su re th a t the fo u n d atio n s a re secure, th a t h aste now will n o t lead to w aste la te r on.
I t is fo rtu n a te fo r the chem ical in d u stry th a t T V A has adopted such an a ttitu d e in its a d m in istra tio n of this basically im p o rtan t legislation. I t m eans th a t ac
tion, w hen it comes, will be deliberate, based on ad e
quate study. W e m ay not alw ays find ourselves in a g reem en t w ith its rulings, b u t th e T en n essee V alley A u th o rity has already w on o u r respect fo r th e w ay it has taken hold o f its job.
Jekyll and Hyde At the W orld’s Fair
I
F S T E V E N S O N ’S fam o u s dual p erso n ality w ere to m aterialize him self in C hicago d u rin g th is y ear of grace, 1933, he w ould find m uch to rem in d him o f the stra n g e c o n tra sts in his ow n tro u b led , fabled existence.A m em orial not alone to one c e n tu ry of p ro g ress in the sciences, b u t to m any cen tu ries, th e In te rn atio n al E x p o sitio n co n tra sts stran g ely w ith th a t F a ir o f only 40 y ears ago w hen the w onders th a t now a re too com m onplace to notice w ere first show n to an am azed w orld.
A stran g e co n trast, too, in th a t Chicago, n ear to b an k ru p tcy as a city, none th e less digs dow n into em pty p riv ate pockets and m iraculously produces w h at is undoubtedly the m ost costly spectacle th e w o rld has ever seen.
S tra n g e co n tra sts also in th e state of hu m an kn o w l
edge a f te r this p a rtic u la r cen tu ry of p ro g ress, fo r w here is th e com parable p ro g ress in culture, in the a rts , in religion, in politics, in hu m an en g in eerin g ? A n d even s tra n g e r co n trasts in science, w hich, w hile it rin g s the electrical carillon in the H a ll of Science tow er, am plifies the b a rk e r’s b e llo w ; w hile it creates the F a ir ’s nightly m iracle of light, supplies the raw m aterials fo r the M idw ay.
A n d yet, w ithal, if at one m inute the F a ir is M r.
H y d e, th e n e x t it is c e rtain to be D r. Jekyll. P len ty of solidity, it has, fo r all a carp in g ed ito r m ay find fault. T o the m an w ith th e tim e and th e w illingness to study, it offers a liberal education. F o r anyone w ith
th e price of adm ission it d raw s aside to m o rro w ’s cu rtain an d d em o n strates again th e old sto ry of th e tra n s fo rm a tion of w o n d ers into com m onplaces. T w e n ty o r th irty thousand engineers a n d scientists will feel them selves purified and hum bled by the ex p e rie n c e; a n d as m any m illion laym en will also go hom e b e tte r citizens.
A New Standard For the Chemical Show
I
T IS N O T too soon to be th in k in g ab o u t th e C hem ical E x p o sitio n . In fa c t b o th th e ex h ib ito rs an d the exposition m an ag em en t can find m uch to th in k about in th e g re a t w ave of p o p u lar acclaim w ith w hich the public has g reeted th e scientific an d com m ercial e x hibits of A C en tu ry of P ro g re ss. Som e will arg u e, of course, th a t the m ak ers of chem ical en g in eerin g m ate
rials an d equipm ent are n o t in terested in the public’s reaction, th a t th ey w a n t to reach only the lim ited circle of th e ir custom ers— actual an d prospective. Such critics m ay lose sight o f th e fa c t th a t th ese custom ers are hu m an beings,- a ttra c te d by th e sam e tric k s an d w illing to be in stru cted — and sold— if the sales sto ry is presented in a novel, in te re stin g an d convincing way.
T h e lesson fro m C hicago is th a t the conventional and com m onplace should no longer be to lerated in in
du strial exhibits. T h e static gives w ay to th e dynam ic presentation, th e p lan t p ictu res to th e dioram as, the c h arts to talk in g p ictu res a n d even to actual p la n t o p er
ations. A new sta n d a rd of show m anship has been d em onstrated and those in th e process in d u strie s w ho w ish to capitalize on chem ical en g in eerin g in te re st n e x t D ecem ber m ay well begin th e ir p lan n in g on such a basis.
A Fitting Memorial For W illiam P. Ryan
N
O T E A C H E R o f the p o st-w ar g en eratio n m ore com pletely dedicated his life to the cause of chem ical engineering education. N o y o u n g er m an of our acquaintance so quickly w on the confidence an d re spect of both his associates and his stu d en ts. A ll w ho cam e in contact w ith him fe lt th a t he h ad a keen, sy m p athetic u n d e rstan d in g of th e ir p ersonal problem s. T o his chosen w o rk B ill R y a n gave u n sp arin g ly of his tim e a n d effort. I t is peculiarly a p p ro p ria te , th e re fo re , th a t those w ho w ere closest to him should su g g est th a t his m em orial take the fo rm o f th e R y an M em orial Scholarship fo r study in chem ical en g in eerin g a t the M assachusetts In s titu te of T echnology. T h ro u g h the A lu m n i A ssociation of th a t in stitu tio n an d th ro u g h a p p ro p ria te com m ittees of th e A m e ric a n In s titu te of Chem ical E n g in e e rs an d th e A m erican C hem ical S o ciety, th e re is now an o p p o rtu n ity fo r co ntributions.N o tim e should be lost in th u s p erp e tu a tin g th e m em o ry o f an o u tstan d in g chem ical engineer, an in sp irin g teacher and a tru e frie n d o f so m any in the p rofession.
338 C h e m ic a l & M e ta llu r g ic a l E n g in e e r in g — V o l.4 0 ,N o .7
Ch emical Engineering mpressions of
A C e n t u r y o f P r o g r e s s
;k C E N T U R Y ago chem istry and electricity could scarcely have been reg ard ed as the prospective X J L bases of a w orld exposition o f science and in d u s
try . T h ey w ere still in th eir in d eterm in ate infancy. A n Englishm an, M ichael F a ra d a y , had in 1833, announced th e laws of electrolysis and electrochem ical action, basing his w ork on facts and principles handed him by the Italian, A lessandro V olta, the F ren ch m an , A . M . A m pere, and th e G erm an, G. S. O hm . F a ra d a y w as m aking a dynam o to harness the pow er of electrom ag
netism , th u s to create the g re a t m otivating force o f the century th a t has ju s t com e to a close.
Liebig, who began the publication of his fam ous A n n a leti in 1832, had laid th e fo u n d atio n fo r ag ricu ltu ral science and w ith Berzelius and W o h le r w as busy c a rry ing fo rw ard the developm ent and application of the atom ic theory, first annunciated by his contem porary, D alton, in 1818. G ay-L ussac and G lover w ere a t work- on w h at a few y ears later (1 8 4 1 ) w as to becom e the lead cham ber process fo r sulphuric acid m an u factu re.
F ro m this background of 100 y ears ago th e re ad er is asked to p ro ject him self ab ru p tly into the m idst o f C hi
cago’s g re a t in tern atio n al exposition— A C en tu ry of P ro g ress. R em em bering the referen ce to the beginnings of chem istry and electricity, it is in terestin g to note th a t everyw here these tw o sciences dom inate— n o t only in the
J u ly , 1933 C h e m ic a l & M e ta llu r g ic a l E n g in e e r in g 339
M O B “-' - O I L R E F IN E P ï
exhibits, b u t in the v ery stru c tu re s of the exposition.
E v ery w h ere is chem istry, everyw here is electricity.
C hem istry in color— new finishes, new m etals, new light sources, new building m aterials, new floorings, new plastics, new photo m u rals of enorm ous size. T h e b u ild ings them selves, w ith th e ir practically w indow less con
stru ctio n , th e ir design fo r u tility — sans flub-dubs— th eir controlled lig h tin g and ventilation, th e ir stro n g , sim ple inexpensive fra m in g and covering, p resage a n o t-d ista n t day w hen m uch of o u r a rc h itectu re will com e sim ilarly to depend on the chem ist, the chem ical engineer and the m etallurgist.
S y n th etic m aterials are everyw here. M any of th e p ig m ents, the tra n sp a re n t, highly-colored M ic a rta “ lam p
sh ad es” fo r the m ushroom light fix tu res th a t illum inate the g ard en areas of the fa ir g ro u n d s ; m uch of th e floor
ing, largely o f c o rk -co m p o sitio n ; m uch o f the siding m aterial w hich includes com position b oard, pressed and various plyw'oods. T h e m odel housing section adds enam eled steel, synthetic stone and glass brick to the e arlier list o f new o r new ly ad ap ted m aterials.
W ith this h asty and quite inadequate in tro d u ctio n to th e exposition as a w hole, the ed ito rs of Chem . & M e t.
w ish to tak e you on a little jo u rn ey , first th ro u g h the exhibits of the basic sciences and then on to the applied
sciences an d some of the com m ercial ex h ib its of chem ical en gineering concern.
T o say m erely th a t th e basic science ex h ib its have been handled adequately w ould be to give scant recognition to the perseverance, ingenuity and intelligence th a t a re evi
d en t in this m ost in terestin g section of the F a ir. A ll science, fo r d em o n stratio n purposes, has been divided into seven d iv isio n s: astro n o m y , m athem atics, physics, chem istry, biology, geology and m edicine, of w hich all b u t the first are allotted- a sh are of th e H a ll of Science.
In tro d u c to ry to m o d ern ch em istry an d physics, both located in the cen tral p o rtio n o f the g re a t U -sh ap ed b u ild ing, is an im posing edifice, 30 ft. hig h and 25 ft. in d iam eter, rep resen tin g a periodic table o f all the 92 know n elem ents. T h is exhibit, illu stra te d on th e opposite page, is crow ned by a large te rre s tria l globe d e m o n stra tin g the relation of these elem ents in the e a rth ’s com position.
P h y sics claim s som e 90 exhibits covering all the essen
tial phenom ena o f this science as it ex ists today. F lam es sing, circu its oscillate, prism s re fra c t, “m olecules” bom bard, strin g s v ib rate b efo re o ne’s v ery eyes and ears.
F u n d am en tals of te m p eratu re an d p ressu re, o f sound, of electricity, of light and o f ra y m a n ife sta tio n s a re p re sented in a m an n er to delight even the m ost hard en ed engineer.
I f th ere is little recognition o f th e b o rd erlan d of physical chem istry, chem istry itse lf, p u re a n d applied, is treated m ost intelligently, i n fact, th ro u g h o u t th e basic science exhibit, the inadequacy o f an y d escriptive pen m akes stro n g ly fo r a w a rra n te d b u t tireso m e flow of superlatives. C h em istry is b ro k en dow n into changes by com bination, by sep aratio n , and by exchange. O p e ra tin g m odels show the difference betw een physical a n d chem ical changes and p o rtra y such reactions as th e com bustion F MATTER,
ISHED IT.
O RG AN IC EVOLUTION THE SC O N C E O F LIFE W A S FIRST SEbN AS A C O S M IC PROGRESSION OF NATURE.
MEN’ d JENNÊ
ΠWTON LAVOISIER! D A L T O N
A T H B M A T Itl - ^ CM » M I S T HY C H B M I 8 T R Y
A t rig h t, a c o m p le te o il re fin e ry , c o n stru c te d of glass, re a lis tic a lly sp lits p e tro le u m in to its co m p o n e n t fra c tio n s a n d p r e p a res th e m fo r p ro d u c ts of com m erce. B e lo w , th e g re a t R o b o t of Science bow s its h e a d in serv ice to m a n k in d a n d m o d e rn
c iv iliz atio n
340 C h e m ic a l & M e ta llu r g ic a l E n g in e e r in g — V o l.4 0 ,N o .7
of iron in oxygen, p h o sp h o ru s in a ir, reduction of m e r
curic oxide to m ercu ry , the com bustion of th erm it, the oxidation and red u ctio n o f sheet copper, the electrolysis of w ater and the use of catalysis in the o xidation of am monia.
O ne of the m ost rem ark ab le of the scale model exhibits in the applied ch em istry section is th e com plete oil re finery co n stru cted , as w ere the oil p ro d u ctio n exhibits in the geology section, u n d e r the auspices of an exhibiting com m ittee re p re se n tin g all o f the principal fa cto rs in the petroleum in d u stry . T h e refin ery illu strated on the op
posite page is supplem ented by dioram as of an oilfield and of a refinery as it actually looks. T h e m odel is m ade alm ost en tirely o f glass and covers som e 300 sq .ft. of space. E x c e p t fo r th e fire reg u latio n s w hich m ake it necessary to su b stitu te realistic dye solutions fo r the v arious oil fractio n s, the m odel is very close to being the real thing. I n the 10-foot distillatio n colum n, fo u r tr a c tions a re taken off. T h e gasoline fractio n goes th rough tre a tin g tow ers, th e kerosene th ro u g h an a g ita to r and batch tre a te r. T h e gas oil is cracked and treated , and the lu b ricatin g fra c tio n chilled and filter pressed. E v en the
B e lo w , th e v is ito r to th e H a ll of S cience is g re e te d b y th is im p re ss iv e re p re s e n ta tio n of th e p e rio d ic ta b le of th e e le m en ts, s u rm o u n te d by a h u g e te rre s tria l g lo b e. A t r ig h t, th e official m ed a l of th e e x p o s itio n , c o m m e m o ra tin g th e
re la tio n of re se a rc h to in d u s try
coke from th e stills and the asp h alt residual from the colum n are shown in the process of being rem oved. S y n chronized voice equipm ent carries the visitor th ro u g h the entire operation.
A lso prom inently fe atu red in the applied chem ical d is
plays are those of rubber, sponsored by F ire s to n e ; and of sulphur sponsored by T e x a s G ulf. In the fo rm er, o perating models show the continuous coagulation of latex by acetic acid and the electrodeposition of rubber.
A n o th er model com pares the p ro p erties of vulcanized and unvulcanized rubber, the fo rm e r w ith and w ithout an accelerator. Still an o th er subject un p ro tected and rubber-protected iro n to the erosion o f a sand blast.
T ex as G ulf S u lp h u r Co. contributed a rem arkable w o rk ing dioram a o f a F ra sc h process su lp h u r m ine, show ing both the surface and the sub su rface equipm ent. Coupled w ith this appears an all-glass su lp h u r b u rn e r supplying S 0 2 to a platinum contact plant, also o f glass. T h e m ist- evofving difficulties of an absorber supplied w ith w eak acid are strikingly displayed th ro u g h the use o f a p re cip itato r which is periodically tu rn e d on and off.
Colloid chem istry is illu strated by m eans of the
• B row nian m ovem ent, by w ater p u ri
fication, by the g rin d in g , tabling and flotation o f gold ores, and by the m aking and b reak in g o f em ulsions.
Union C arbide and C arbon C orp. is sponsor fo r a g ro u p o f applied chemical d em onstrations including one show ing the relative p ro p erties of the com ponents of a ir ; an o th er show ing the spectra of a ir co n stitu ents ; a g ro u p covering the principles of a ir liquefaction by cooling, by p ressu re and by e x p a n sio n ; and an electrochem ical g ro u p show ing elec
tric fu rn aces in operation, the fo r
m ation o f calcium carb id e; and the production o f chrom ium plated w a re ; and the ox id atio n by a ir of nitrogen fo r the production of H N O n by the arc process.
M edical sciences w ere rep resen ted by m any of the w o rld ’s leading in stitutions. E x h ib its covered m edi
cine, d e n tistry an d pharm acology and centered aro u n d a tra n sp aren t, life-sized model of a m an, built in D resd en by th e D eutsches H ygiene M useum , fo r the illustration of body functions. O n e of the m ost fascinating of the exhibits w as th a t o f the W ellcom e R esearch In s ti
tution of E n g lan d , com m em orating the w o rk of the A m erican, S ir H e n ry W ellcom e, who w as respon
sible fo r th e conquest of yellow fever an d o ther tropical diseases.
B u t even though chem ical engineers are hum an we m u st pass on now to th e in te re stin g com m ercial exhibits, or ra th e r to a few o f th e m any th a t cam e to o u r atten tio n in som e fo rty m an-hours o f b row sing in the g re a t H all of Science.
A m ong the applied-science ex h ib its a re several excel
len t ones in th e chem ical and allied field, w hich a re to be fo u n d on the g ro u n d floor of th e H a ll of Science building.
M ost extensive of these is th a t o f th e U n io n C arbide
& C arbon C orp., covering such d iv erse subjects as liquid a ir and acetylene; w elding e q u ip m e n t; flash lights, b at
teries, u ltra violet equipm ent an d o th e r carbon p ro d u cts ; allo y s; V inylite, solvents and o th e r chem ical products.
In a th eater seating p erh ap s 100 people a d em o n stra to r gives fre q u e n t lectures on liquid a ir, w hile a t in terv als a w elder ap p ears in th e bottom of a copper-lined p it to
O il field d io ra m a w ith d r illin g o p e r
a tio n s in f u ll b la s t S cale m o d el d e r ric k s in o p e ra tio n , one 10 an d th e o th e r 13 ft. h ig h (S h o w n b y th e E x
h ib ito r s ’ C o m m it
tee of th e P e tr o leu m I n d u s try )
A bove: T h re e of th e r u b b e r in d u s try e x h ib its (s p o n s o re d b y F ir e sto n e ) sh o w in g c o ag u la tio n of la te x , c o m p a r
iso n of v u lc a n iz e d and u n v u lc a n iz e d r u b b e r , a n d the co m p a rativ e a b ra sio n re sista n c e of
ste el an d r u b b e r
R ig h t: T exas G u lf S u l
p h u r Co.’s o p e ra tin g d io ram a of a F rascli p ro c ess s u lp h u r m in e
C h e m ic a l & M e ta llu r g ic a l E n g in e e r in g — V o l.4 0 ,N o .7
d em o n stra te the w elding an d cu ttin g torch. O n e o f the m ost strik in g d io ram as o f th e e n tire F a ir is C arb id e’s g ro u p in g o f 16 o f its 166 plants.
V ic to r Chem ical W o rk s is displaying a larg e model of its N ashville b last-fu rn a c e phosphoric acid plant. T he model n o t only follow s every detail of the actual plant ( C liciii. & M et., Ju n e , 1933, p. 2 8 3 ), b u t continuously d isg o rg es “ sla g ” fro m its blast fu rn ace and “acid ” fro m its h y d ra tin g to w er an d p recip itato r. A d em o n stratio n o f phosphoric acid ’s n u m ero u s uses com pletes the d is
play.
F in e chem icals an d pharm aceuticals likew ise have th eir C o m p le te to th e last
d e ta il, V ic to r C h e m ic al W o rk s ’ o p e ra tin g m o d e l of its b las t-fu rn a ce p h o s p h o r ic a cid p la n t show s th e c o n tin u o u s c h arg in g of th e fu rn a c e , d isc h arg e of th e slag , a n d outflow
of th e acid
A few of th e e x h ib its of U n io n C a rb id e a n d C a rb o n C orp., in c lu d in g , at th e ex
tre m e le ft, a m o d el e le c tric fu rn ac e , a n d b elo w it, a d io ram a of 16 of its p la n ts ; at rig h t, a sta tu e a n d d isp lay on fe rro u s allo y s, an d b elo w th e c e n tra l g ro u p th at rises a b o v e an e x h ib it sh o w in g th e sp re a d of sy n th e tic c h em istry
A u to m a tic ru b b e r ro ll w h ic h co m p o u n d s th e W o rld ’s F a ir t i r e s ; t i i c tra v e lin g k n ife re du ces th e la b o r to m e re su p e rv isio n
S te el’s s e v e r a l fa ce s: L eft, sym b o lic g ro u p show n by U. S. S teel to p o r tr a y th e m a te r ia l’s se rv ic e to
h u m a n ity R ig h t: S teel even c lo ser to h o m e — th e A rm co - F e rro E n a m e l h o u s e w ith a ll e x te rio r s u r
faces s h e a th e d in e n a m e le d steel
crude ru b b er to the final inspection an d w ra p p in g of the finished tires.
In the food g ro u p , M o rto n S a lt Co. h as a life-lik e cross section of a p lan t fo r both p an and g ra in e r salt, w hile N atio n al S u g a r R efining Co. of N ew Je rse y show s an o th er cross section of a com plete su g a r refinery. In th e G eneral E x h ib its B uilding one pavillion is largely given over to U . S. Steel C orp. an d its subsidiaries, w h ere o p eratin g dio ram as show th e steps in steel p ro d u c
tion w hile n u m ero u s articles and u tensils a tte s t to the m anifold uses of steel alloys. A sym bolic pile in the center of the hall, illu strated below, p resen ts th e d iv ersity o f steel’s applications in u n fo rg e ta b le fashion. N earb y is the ex h ib it of the P a p e r F o u n d a tio n w hich co n tra sts the hand m aking o f p ap er w ith m achine m a n u fa c tu re in an op eratin g model o f a F o u rd rin ie r m achine, p e rfe c t yet b u t 10 ft. long.
N o chemical engineer, o f course, will atten d the F a ir sim ply to exam ine his ow n specialties. T h e re are p ro fit
able days to be sp en t in o th e r field s: in T ra v e l and T ra n sp o rt, in M o to rs, in R adio, C om m unications and E lectricity, in the ex h ib its o f G o v ern m en t an d S tates, in F ood, A g ric u ltu re and allied gro u p s. H e will w a n t to peer into th e fu tu re o f h o u sin g an d ex am ine th e new ly adapted m aterials lavishly em ployed. T h ese a n d a th o u sand o th er fe atu res a re m ore th a n sufficient to g u a ra n te e lame m uscles and w o rn shoes fo r every 1933 ex p lo rer who w ould discover the full m ean in g of A C e n tu ry o f P ro g ress.
rep resen tativ es in the H all of Science. M erck & Co.
m akes m ost effective use of larg e m asses of highly colored cry stals contained w ithin glass colum ns. A n a rra y o f ra re chem icals in u n ifo rm bottles ad d s to the im pressiveness of the exhibit. E . R . Squibb & Sons con
tra s ts a display of m odern pharm aceuticals w ith a m ediaeval apothecary shop carried out to th e last detail.
M allinckrodt Chem ical W o rk s re tu rn s to the action them e o f the basic science exhibits w ith w o rk in g m odels show ing the distillation of m ercu ry and the sublim ation of iodine. A b b o tt L ab o rato ries goes extensively into the pro p erties and applications o f the vitam ins in foods and in pharm acy.
O u tsid e the H a ll o f Science a re o th er in d u strial d is
plays of p artic u la r chem ical en gineering note. T h a t of the F iresto n e T ire & R u b b er Co. is the m ost am bitious.
I n ad d itio n to a very th o ro u g h tre a tm e n t of all o f its products, the com pany has set up a com plete tire plant, b eau tifu lly constructed, w h ere half a th o u san d potential custom ers can w atch every step from the m illing o f the
In F i r e s t o n e ’ s W o rld ’s F a ir tire p la n t: C h ro m iu m p la te d w a tch case v u lc a n iz e rs t h a t o u ts h in e an y seen b e f o re ; an d b e
low —
344 C h e m ic a l & M e ta llu r g ic a l E n g in e e r in g — V o lA 0 ,N o .7
Cement Industry Looks Toward
Byproduct Potash Recovery
By P. E. L A N D O L T
C o n su ltin g E n g in e e r N e w Y o r k C ity
W I T H T H E B L O C K A D E ag ain st G erm an com m erce d u rin g the W o rld W a r, a serious sh o rt
age o f p o tash fo r fe rtiliz e r de
veloped in th e U n ite d S tates and prices rose to ten tim es th e ir p re vious levels. G re a t in g en u ity w as displayed in finding new potash m aterials an d in e x tra c tin g or p ro d u cin g potash salts. F o r e x am ple, kelp, lake b rin es in N e b ra sk a an d C alifornia, iron b la st-fu rn a c e operatio n s, green sands, p o rtla n d cem ent m a n u fa c tu re, an d o th e r sources w ere all called upon to help supply th e dem and.
E x a m in a tio n o f th e ra w m aterials fo r cem ent m a n u fac tu re indicates th a t a t m an y cem ent m ills th e lim estone, o r shale o r clay, contains appreciable q u an tities o f potash (a n d s o d a ), usually as silicates. In m ost instances the ratio o f K 20 to N a 20 is 3 o r 4 to 1. O rd in a rily one- h alf to tw o -th ird s o f th e alkali in the raw m aterials rem ain s in th e clinker p roduced. T h e balance is vola
tilized a n d carrie d off by th e flue gases in th e fo rm o f fum e. T h e volatilized alkalis com bine w ith su lp h u r from th e fuel o r ra w m aterial to fo rm sulphates. W ith a defi
ciency o f su lp h u r, carb o n ates a re fo rm ed . W ith ch lo r
ides p resen t, th e volatilized po tash w ould be p resen t in th e fu m e as a m ix tu re of chloride an d sulphate. W ith pow dered coal used as fuel, som e of the volatilized p o t
ash com bines w ith silica in th e coal ash to fo rm an acid- soluble potash.
T h e first m a jo r developm ent o f p o tash recovery fro m cem ent m a n u fa c tu re w as m ade a t the R iv ersid e P o rtla n d C em ent Co. a t R iv ersid e, C alif., in 1910-11. T o abate a d u st nuisance the C ottrell process o f electrical p recipi
ta tio n w as applied (S ch m id t, T ra n s . 8th In t. C ongress A p p l. C hem ., 1912) a n d la rg e q u an tities o f d u st co n tain in g finely divided raw m aterial, p a rtly calcined m aterial and alkali salts w ere recovered. A nalysis o f the raw m aterial in d icated an av erag e p o tash co n ten t o f 0.5 to 0.6 p e r cent K 20 . T h e d u st and fu m e recovered in th e C o ttrell eq uipm ent analyzed, ov er an e x ten d ed period, 2 to 4 p e r cent w ater-soluble K 20 . S tu d y of kiln o p eratio n s led to increased volatilization o f p o ta sh and ad d itio n s, such as increased lim e content and salt, w ere
m ade to the raw m aterial. A lso, the d u st and fum e col
lected w ere re-treated in a second kiln operation, resu lt
ing in a p ro d u ct collected fro m the second kiln gases containing 20 to 22 p er cent w ater-soluble K 20 .
D u rin g the period 1915-17, a C ottrell installation w as built a t the p lan t of the S ecu rity C em ent & L im e Co., near H ag ersto w n , M d. A n o th er installation in the E a s t
ern U n ited S tates w as built a t the D e x te r P o rtla n d C em ent Co., at N azareth , P a. A n installation o f C ottrell equipm ent an d a leaching p lan t w ere also bu ilt a t th e Iro n to n P o rtla n d C em ent Co. a t Iro n to n , O hio. A f u r th er developm ent w as m ade a t the S a n ta C ruz P o rtla n d Cem ent Co. a t D avenport, C alif. (Iv ra ru p , Chem . & M et., 25, 1921, p. 3 1 6 ). A t this p lan t th e kiln gases w ere scrubbed in tow er w ashers, recircu latin g th e w ash w ater.
A fte r w ashing th e gases and cooling them they w ere passed to excelsior filters, w hich w ere la te r replaced by C ottrell p recip itato rs of a special type. E ventually, potash-bearing m aterial containing 30 p er cent o r m ore w ater-soluble K 20 w as produced.
P o tash recovery in p o rtlan d cem ent m a n u fa c tu re has several distinct lim ita tio n s : first, it is dependent on the
F ig. 1— M u ltic lo n e co lle cto rs fo r p o tas h -h ea rin g d u st in N o rth A m e ric an C em en t C o rp .’s p la n t
prim e p roduction of p o rtla n d cem en t; second, on the price of po tash salts obtained from salt deposits, such as S ta s s fu rt or C arlsbad. F o r the m a n u fa c tu re of p o rt
land cem ent a total plant investm ent o f $2 to $4 is r e q uired fo r each annual b arrel of cem ent produced. F ix e d charges on such an investm ent applied to po tash alone w ould be prohibitive u n d er norm al conditions, to say nothing of the disposal of the clinker produced.
U sually, unless the raw m ix fo r the m a n u fa c tu re of cem ent contains over 0.75 p er cent K 20 , th e am o u n ts of w ater-soluble potash recoverable fro m the gases do not ju s tify a recovery plant. A t one o r two. plan ts in the U n ited S tates the raw m ix contains as m uch as 1.75 p er cent total K 2O, an d m any plan ts show an analysis o f raw m aterial o f 1 p er cent, plus o r m inus. In m ost cases the soda content is low. A n analysis in 1917 o f th e raw m aterials fo r cem ent m an u factu re used in the plants of the U n ited States, m ade by th e B u re a u o f Soils (U .S . D ept, of A g ricu ltu re, Bull. 5 7 2 ), show s th a t about one- th ird o f the plan ts h ad sufficient po tash in the raw m ate
rials to ju s tify recovery. T h e potential to n n ag e th u s show n ap p ro x im ates 50,000 tons o f K 20 p e r annum , w hich is ap p ro x im ately 20 p er cent o f th e average annual U .S . consum ption o f potash fo r a g ricu ltu ral purposes.
T hese figures are based on a cem ent p ro d u ctio n o f about 150,000,000 bbl. p e r year.
O rd in a rily only on e-th ird to one-lm lf o f the potash in the raw m aterial can be considered recoverable. T h e balance is lost to th e clinker. H a r d e r b u rn in g o f th e raw m ix in th e kiln, increase in the lim e co n ten t o f the m ix, o r addition o f volatilization ag en ts m ay b rin g about an increase to p erh ap s 75 p e r cent. I t m ay also be fo u n d practical to volatilize m ost o f th e residual p o tash from the cem ent clinker. T heoretically, all o f th e potash can be volatilized by increased te m p eratu re, as show n by N estell and A n d erso n ( / . In d . E n g . C hem ., 9, 1917, p. 6 4 6 ), and by increasing the lim e co n ten t in th e raw m ix. H ow ever, a p rereq u isite to m odifications o f the process o f b u rn in g such a m ix tu re to clinker is th e p ro duction of quality cem ent. A dvances in th e a r t of cem ent m aking in general fav o r increased volatilization.
P o w d ered coal fuel operates adversely to th e ex ten t th a t som e o f the p o tash recom bines w ith th e silica in the coal ash. A b o u t one-half of th e coal ash is com bined in th e clinker, about one-h alf is carried out o f th e kiln by th e flue gases.
C ottrell flue d u st fro m cem ent-kiln gases usually con
tains, in plan ts having p o tash -b earin g m aterials, about 8 p er cent to tal K 2O , of w hich ab o u t one-h alf is w a te r soluble. Such m aterial is not readily salable except p e r
haps as a low -priced soil dressing. I t m ust eith er be leached or p u t th ro u g h secondary volatilization fo r f u r th er co n centration of its p otash content. E ith e r o p era
tion is so expensive as to ren d e r it unprofitable at o rd in ary m a rk e t levels. A serio u s difficulty is fo u n d in leaching such m aterial due to the fo rm atio n of syngenite, a double sulphate o f lime and potash, w hich is insoluble.
U se of scrubbers fo r rem oving dust, as had been p ra c ticed a t the S a n ta C ruz P o rtla n d C em ent Co., is ex p en sive. F o r econom y of w ash w ater, provision m u st be m ade fo r recirculation in w hich an appreciable concen
tratio n o f calcium sulp h ate builds up, rap id ly salting out in the p ip e'lin es, connections and pum ps, and n ecessitat
ing heavy- m aintenance costs, o r even d uplicate p iping an d pu m p in g equipm ent th ro u g h o u t.
M u lticlon e R ecovery Process
D u rin g th e y ears 1928 and 1929 a new m echanical d u st collector w as developed, kn o w n as th e M ulticlone (L issm an , C hem . & M e t., 37, 1930, p. 6 3 0 ), w ith w hich tests w ere m ade at th e p lan ts o f th e R iv ersid e a n d S an ta C ruz P o rtla n d C em ent Cos. to d em o n strate its possibili
ties as a d u st collector on cem ent-kiln gases. T h ese tests indicated th a t the bu lk o f th e d u st w as rem oved fro m the gases, and m ost o f the fu m e escaped. T h is sep aratio n w as ap p aren tly an en tirely m echanical one based on the relative size o f th e particles, th e fum e p articles being finer th an 1 m icron in diam eter. M ulticlones w ith 9-in.
F ig . 2— T o p v iew of M u ltic lo n e c o lle cto rs
d iam eter tubes show ed slightly b e tte r fractio n atio n th a n those w ith la rg e r d iam eter tubes.
T e sts w ere repeated a t th e N o r t h ’A m erican C em ent Corp., a t S ecurity, M d., (fo rm e rly S ecu rity C em ent &
L im e C o.) in 1929 an d 1930 w ith like resu lts, b u t in these tests 9-in. d iam eter M ulticlone tubes show ed a decidedly b e tte r fractio n atio n th a n 16 o r 24-in. d iam eter tubes.
T h e v ariatio n betw een these tests an d those m ade a t the W e ste rn p lan ts w as probably due to th e presence o f coal a sh a t the S ecu rity tests. T h e kilns in th e W e ste rn p lan ts w ere oil o r gas fired.
T h e S ecu rity plant has five kilns, 8 ft. in d iam eter and 125 ft. long, w ith a 40 ft. length 10 ft. in diam eter. T h e m axim um capacity is 5,000 bbl. o f clinker p e r day, m ade by the d ry process. H o t gases fro m th e kilns are deliv
ered to th ree w aste-h eat boilers, each equipped w ith w aste-h eat e x h au st fans. S team fro m these boilers g en
erates all the pow er fo r p lan t o peration, w ith som e s u r
plus p ro d u ctio n periodically.
346 C h e m ic a l & M e ta llu r g ic a l E n g in e e r in g — V o l.4 0 ,N o .7
In 1930 a C o ttrell p re c ip ita to r w as installed a t S e
cu rity fo r d u st recovery. W ith this equipm ent installed, and w ith the possibilities o f th e M ulticlone show n, it w as decided to install M ulticlones an d o th er equipm ent fo r a com plete b y p ro d u ct p o tash recovery operation. G ases from th e w aste-h eat boiler fan s w ere delivered to a large M ulticlone installatio n th ro u g h a connecting flue system , thence to a sp ray cham ber, w here w a te r u n d e r hig h p re s
su re w as atom ized into the hot gases, reducing th eir te m p eratu re fro m ap p ro x im ately 300-350 deg. F . to 200- 250 deg. F . F ro m th e sp ray cham ber th e gases w ere passed th ro u g h th e C ottrell p re c ip ita to r in w hich th e p o t
ash co n cen trate w as collected, an d th en th e gases w ere
I
F ig . 3— S p ray c h a m b e r a n d M u ltic lo n e u n it
passed th ro u g h th e stack fo r discharge to atm osphere.
T h e M ulticlone installation consists o f six units, T y p e 10^ V B , size 48, w ith a to tal o f 288 tu b es 10^- in. in d iam eter. T h e u n its are set in tw o row s o f th ree each, an d th e flues a re equipped w ith d am p ers so th a t vario u s com binations o f u n its can be o p erated to g eth er. T h e flues a re designed to p erm it the subsequent installation o f fo u r ad d itio n al u n its. T h is p a rtic u la r type o f M u lti
clone, ra th e r th a n th e 9 V A type, w as installed m erely because o f the availability o f th e designs a t th e tim e.
In subsequent p lants, 9-in. tubes will be specified.
R efe re n c e to F ig . 1 show s o utline details o f th e M u lti
clone installation. T h e collected d u st is d ropped from th e hoppers by m eans of tip p in g valves to screw con
veyors, w hich tra n s p o rt it to a 60-ton d u st sto rag e tank, fro m w hich it is re tu rn e d to th e ra w g rin d in g d e p a rt
m en t by m eans o f a F u lle r-K in y o n pum p system , and blended .w ith new raw m aterial. T h e to p o f th e o u tlet flue o f th e M ulticlone, w hich is im m ediately above the
individual outlet tubes, is fitted w ith covered openings th ro u g h w hich these tubes, and p articu larly the small du st th ro ats a t th e bottom of the collecting tubes, can be cleaned out. C leaning has proven necessary occasionally, p articu larly a fte r a tem p o rary b reakdow n of th e dust- rem oval system w hen the hoppers fill u p as well as p a rt o f the tubes them selves. S im ilar openings are also p ro vided on the sides o f the inlet flues th ro u g h w hich the sep aratin g vanes can be blow n off w hen necessary w ith com pressed air.
T h e spray cham ber w as designed and installed a fte r th e rest o f th e equipm ent had been in o peration fo r a sh o rt w hile an d had, th erefo re, to be fitted into th e space occupied by the existing flue fro m the M ulticlone to the precipitator. I t is nevertheless serv in g its m ain purpose satisfactorily. T h is s tru c tu re is show n in F ig . 3 and consists essentially o f a rectan g u lar steel cham ber w ith a flat bottom . It is equipped w ith about 120 sm all sprays inserted from the top and tw o sides. T h ese consist o f a sm all head, to give the w ater a w h irlin g m otion, closed by a th in disk w ith a small central orifice of -g^-in. d iam eter. A t a w ork in g p ressu re o f 250 lb. p er sq.in. these sprays deliver fro m 0.2 to 0.3 gal. p er m inute, sufficiently finely atom ized th a t about 70 p er cent is actually evap
orated. T h e w ater is delivered to the sprays by a high- pressure, m ulti-stage cen trifu g al pum p.
D u st separated by th e w ater collects in p a rt on the walls, from w hich it is periodically dislodged by rap p in g the walls a t designated points, o r “ b u tto n s,” w ith a ir ham m ers. P rovision has been m ade fo r clarify in g the unevaporated spray w ater in settlin g tan k s and re tu rn in g it in the form of a coarser spray to th e spray cham ber, w hile th e solids a re re tu rn e d to the raw m aterial d ry e rs and thence to the blending system and kilns.
T h e p recip itato r is o f the stan d ard ro d -cu rtain type, consisting of tw o units w ith th ree sections of 18 d u cts each. T h e rod cu rtain s are ab o u t 12 ft. long an d spaced 8 in. a p a rt w ith ¿-in. square, tw isted ro d s as discharge electrodes. T h e effective discharge len g th is about 15,000 ft. Collected m aterial is carried to the end o f the hop
pers by m eans of screw conveyors from w hich it is tra n s p orted to the potash storage bins by m eans of a special F u ller-K in y o n pum p.
O perating E xperiences
F ro m Ja n u a ry to Ju ly , 1932, the operations w ere closely studied to d eterm ine optim um conditions o f o p er
ation of the M ulticlone an d C ottrell p recip itato r, sim ul
taneously w ith the operation o f cem ent m an u factu re.
M any variations occurred in operation w hich w ere re flected in th e operation o f the potash process. A lso num erous small o p eratin g defects developed in the use o f th e M ulticlones and the spray cham ber, w hich w ere n o t unusual in th e tria l o f new equipm ent u n d er new o p eratin g conditions. T h ese difficulties w ere prim arily those involving th e rem oval o f the collected m aterial, an d w ere finally solved by a carefu l stan d ard izatio n o f o p er
atin g routine. In general, the o peration of th e M u lti
clones and related equipm ent w as m ore o r less autom atic.
D u rin g th e trial o f th is process, cem ent mill operation w as quite irre g u la r on account of th e generally bad tra d e conditions prevailing at th a t tim e. T h e p la n t operated p a rt o f th e tim e w ith th re e kilns and p a rt w ith tw o. P ro duction p e r kiln w as generally low. O n fo u r kilns o n ly
3,500 bbl. of clinker w as m ade per 24 h o u r s ; on th ree kilns, 2,600 b b l.;
on two kilns, 1,800-2,000 bbl.
A n endeavor w as m ade to reduce the potash in the clinker to 0.6 p er cent. T h e raw m aterial contained 1.0- 1.1 p e r cent K 20 . T h e potash in the clinker averaged 0.8-0.9 p er cent.
T h is resulted in a low ered recovery.
K iln d ra fts w ere varied , resu ltin g in variable d u st loss and variable vola
tilization. M uch w ork rem ained to be done to in su re m ax im u m volatili
zation. P arallel w ith the potash re covery tests, kiln operations w ere carefu lly studied, w ith the resu lt th a t a g re a t deal of valuable in fo rm atio n on optim um d ra fts , fuel consum p
tion, excess air, kiln o u tp u t an d o ther facto rs w as obtained.
T h e M ulticlones w ere norm ally operated on a p ressu re d ro p o f 3-4 in.
w .g., usually th ree M ulticlones of 48
tubes o p eratin g fo r th re e kilns. T h e re w as no w ay of a d ju stin g th e M ulticlone tubes easily to th e volum e p a ss
ing. M ulticlone d u st efficiency v aried w idely as a result.
O v er 90 p er cent efficiency w as obtained, b u t a t tim es this d ropped to 80 p er cent. A b o u t 45-50 lb. o f d u st p e r b arrel o f clinker produced w as collected in the M u lti
clones, o r about 8 p er cent of th e ra w m ix feed. A t tim es this increased to 15 p e r cent. T h e M ulticlone d u st w as m ixed w ith the raw m aterial in a blending system , w ith correction fo r the low lim e in th e dust.
M ulticlone o peration w as practically au to m atic except fo r the “lancing” of th e d u st th ro a ts a n d vanes about once a w eek, an o p eratio n re q u irin g ab o u t 1 to 2 hours tim e o f one m an.
T h e m aterial collected in th e M ulticlone av erag ed 99 p er cent th ro u g h 100 m esh, 93 p e r cent th ro u g h 200 mesh an d 85 p e r cent th ro u g h 325 m esh. T h e av erag e chem ical analysis of this m aterial w as as show n in T able I.
T a b le I — C o m p o sitio n of M u ltic lo n e D u st
C & O ....
S i O . . . . , F e i O i . . . A l t O i . . . M g O . ..
S ...
P e r C e n t 48 . 10 1 6 .3 6 3 .7 9 5 . 19 2 .3 3
0 .0 8 T o t a l .
P e r C e n t 1 2 .3 5
0 . 2 0 5 . 19 5 .8 8 9 9 .4 7 *
♦ B a la n c e N a iO a n d a c c u m u la te d e rro r.
F ro m the M ulticlone the gases e n te r the sp ray cham ber, w h ere about 30 gal. of w a te r p er m in u te is atom ized, o f w hich about 20 gal. is ev ap o rated an d 10 gal. flows out o f th e bottom of th e sp ra y cham ber. T h is ev ap o ra
tion and cooling reduces the te m p e ra tu re of the gases to ab o u t 200 deg. F ., w ith a dew point of ab o u t 100-110 deg. F .
D u rin g th e operation in 1932 ap p ro x im ately 5,000 lb.
of m aterial p e r day w as rem oved in th e sp ray cham ber, largely as m ud, b u t p a rtly as dissolved p o tash salts c a r
ried aw ay w ith th e w aste w ater. A s a re su lt o f m odifi
cations in the equipm ent m ade d u rin g th e w in te r shut-dow n th e am o u n t o f m aterial rem oved in the sp ray cham ber has been appreciably reduced.
P o tash salts re p resen tin g about 1,500 lb. o f K 20 p er
F ig . 4— C o ttre ll p r e c ip ita to r top
day w ere fo rm erly lost w ith th e w aste w ater, b u t p ro vision h a s . been m ade to recircu late th is w aste w ater, thereby recovering th e bu lk of th ese p o tash salts.
S tress m u st be laid on the fact th a t hum idification or sp ray in g o f th e gases w ould be very troublesom e if the e n tire q u a n tity of d u st w ere p resen t. T h e bu lk of th e d u st has been rem oved in th e M ulticlone, leaving only the finest and lig h test m aterial to be sep a ra te d in w et condi
tion. T h e sp ray cham ber also serves som e fu n ctio n in fu rth e r in creasin g th e con cen tratio n o f the po tash fum e by the rem oval o f fine d ust, w hich is relatively low in potash. T h e sp ray-cham ber d u st contains less th a n 1 per cent Iv20 .
H ig h C o ttre ll E fficiency A tta in e d
L ittle stress need be laid on the C ottrell o peration, w hich w as q u ite norm al an d in w hich a hig h degree of recovery w as obtained. T h e efficiency o f rem oval of to tal solids in th e C o ttrell installatio n exceeded 95 p e r cent, including electrode ra p p in g periods, an d periods w hen th e “ lancing” o f th e b o iler tu b es to rem ove d u st greatly increased th e d u st co n ten t o f th e gases.
In the m aterial collected by th e p re c ip ita to r th e aver- age co ncentration of w ater-so lu b le po tash fo r th e m onth o f Ju ly , 1932, w as alm ost 21 p e r cent. W ith an actual clinker p roduction o f 2,000 bbl. p e r day d u rin g th a t m onth, ap p ro x im ately 600,000 lb. o f m aterial w as col
lected, containing ab o u t 120,000 lb. o f K 20 , w a te r soluble. A b o u t 95 p e r cen t o f th e to ta l p o tash in this m aterial is w a te r soluble. C hem ical analysis o f an a v e r
age sam ple fro m 10 days collection in th e C o ttrell p re cip itato r w as as show n in T ab le II .
O p eratio n s in S eptem ber, O cto b er an d N ovem ber, 1932, p roduced m aterial hav in g an average o f 25-28 p er cent w ater-soluble K 20 , w ith m aterial in th e th ird or last p re c ip ita to r section hav in g analysis as hig h as 40 p e r cent w ater-soluble K 20 .
A p o tash -reco v ery balance based on an av erag e p ro duction o f 3,000 bbl. of clinker p er d ay is given in T able I I I .
Since the installation a t S ecu rity w as laid out to suit
348 C h e m ic a l & M e ta llu r g ic a l E n g in e e r in g — V o l.4 0 ,N o .7
ex istin g conditions an d w as p lanned initially fo r dust recovery only, its lay o u t is n o t th e best possible. T h e layout show n in F ig . 5 co n stitu tes a m ore or less ideal system . E a c h boiler fan w ould be equipped w ith a set of M ulticlones w ith sufficient flexibility to p e rm it the sh u t-d o w n o r isolation o f any M ulticlone unit. T h e sp ray system w ould be designed to p erm it p artial sh u t
dow n fo r cleaning, re p airs o r o th e r atten tio n . T h e C ot
trell p re c ip ita to r w ould also be designed fo r g re a te r flexibility th an th e p re se n t u nit, an d th e p otash storage w ould be b u ilt as a p a rt o f th e p re c ip ita to r stru c tu re fo r econom y a n d convenience.
In p lan ts w h ere w aste-h eat boilers are n o t installed, som e provision fo r cooling m u st be m ade, b u t M ulticlone installations built o f steel can be operated up to 1,000 deg. F ., and, if need be, alloy co n stru ctio n can be used fo r h ig h er tem p eratu res. T h e p re c ip ita to r co nstruction w ould be th e sam e, ow ing to th e in terp o sitio n o f the sp ray cham ber. In th e case o f w et-process cem ent plants it is m ore th a n likely th a t th e sp ray cham ber can be en tirely elim inated.
O p e ra tio n of the S ecu rity installation has not been T a b le I I — T y p ic a l A n a ly sis of C o ttre ll-C o lle c te d D u st
-W ater Soluble-
P e r C e n t P e r C e n t
C a O ... C a O ... 7 .4 2
S ÍO2... 9 .6 2 M g O ...
F e î 0 3 ... 2 .0 6 S O3... 2 3 .0 7
A I2O3... K s O ... 2 0 .2 7
S 0 3... 2 9 .8 3 N a jO ( e s t . ) ... 1 .2 9 K * 0 t o t a l ... 2 0 .8 0
N a tO ...
C O * ... 2 .7 8 S ...
H , 0 ...
M g O ...
C l ... n o t d e te r m in e d , p r o b a b ly 0 . 5 ± T o t a l ... 9 9 .4 1
c a rrie d on over a sufficiently long period to ju s tify full a n d com plete cost figures, b u t the d a ta o f T ab le I V are indicative o f the conditions prevailing.
T o offset these costs, c red it m u st be given to the du st re tu rn e d to th e ra w m ix w hich is g ro u n d an d dried, and p a rtly calcined, a m o u n tin g to 60-75 to n s p e r 24 h o u rs, h av in g a value as. raw m aterial o f $0.50 p e r ton, or
F ig . 5— S u g g ested la y o u t of p o ta s h re co v e ry e q u ip m e n t fo r a 4,500-bbl. cem en t p la n t
$10,000-$ 12,000 p er annum . In the average plant equipped it would be fa ir to assum e th a t the value o f th e d u st collected and retu rn e d to th e system w ould offset the charges fo r the operation o f th e en tire bypro d u ct plant.
P o tash recovery on the 2,600-bbl. clinker p roduction of 12.5 tons p er day o f 21 p er cent K 20 w ould have an
T a b le I I I —T y p ic a l P o ta sh B a la n ce 1 b b l. o f c e m e n t
I b b l. o f clin k e r I b b l. o f k iln feed
376 lb . 370 lb.
570 lb . p lu s d u s t r e tu r n e d L b . K iO P e r B b l.
P o ta s h in ra w m a te r ia l, 1 .0 5 % K jO 5 .8 9 C lin k e r 0 .8 0 % KjO ... 2 .9 6 G a s e s ... 2 .9 3
(C irc u la tin g b e tw e e n k iln a n d M u lti
clo n e, 46 lb . of d u s t p e r b b l. c a rry in g 6 % K : 0 , 2 . 75 lb . KsO)
E n te r in g s p r a y c h a m b e r, I2 1 b ./b b l 2 .9 3 L e a v in g s p r a y c h a m b e r in w a te r 2 l b ./ b b l. 0 .5 7
(re c o v e ra b le b y re c irc u la tio n )
L e a v in g s p r a y c h a m b e r in g a s e s 2 .3 6 C o lle c te d in C o ttr e ll p r e c i p it a to r 2 .2 1 L o s t in s ta c k g a s e s ... 0 .1 5
N e t V o la tiliz a tio n ... 4 9 % a p p ro x .
N e t R e c o v e ry of M a r k e ta b le P o ta s h 47 c/g a p p ro x . (in c lu d in g s o lu b le KjO in w ash w a te r)
L b . K iO P e r D a y 17,670
8,880 8,790
8,790 1,710 7,080 6,630 450
average w orth of $125 or, annually, ab o u t $40,000. A t 5,000 barrels, this would m ean a t least $75,000 p e r year.
T hese recovery figures a re based on w hat has been con
sidered a reasonable average price fo r potash, b u t u n d er p resen t stress conditions these figures m u st be reduced appreciably.
T h e foregoing indicates th e possibilities o f potash re covery, b u t th ere is fu rth e r o p p o rtu n ity fo r tria l and developm ent w hich m ay lead to even m ore prom ising results. Such concentrated m aterial m ay also be fu rth e r refined a t a reasonable cost to produce h ig h -g rad e po tash salts fo r o ther in d u strial purposes. B y fu rth e r control
T a b le IV — A d d ed C osts fo r P o ta sh R eco v ery
K w .- H r . p e r D a y A d d itio n a l lo a d o n b o ile r fa n s to o v e rc o m e re s is ta n c e th r o u g h
M u ltic lo n e s a t 3-4 in . w .g ... 1 »500
P o w e r fo r h ig h -p re ss u re p u m p ... >20
P o w e r fo r screw co n v e y o rs a n d F u lle r - K in y o n p u m p ...
P o w e r fo r C o ttr e ll e q u i p m e n t... 600 T o t a l ... 2 .470
D o lla rs p e r D a y P o w e r fro m w a s te - h e a t b o ile rs (less th a n $ 0 .0 0 5 p e r k w .- h r .) . , 12 L a b o r, tw o m e n o v er th r e e s h if ts ... 9 R e p a ir s a n d m a in te n a n c e ... ...
T o t a l ...,... 26 A n n u a l T o ta l, 330 d a y s ... 8,580
o f kiln operation or addition agents to the m ix, g re a te r potash yields m ay be expected w ith no g re a te r in v est
m ent.
T h e potash concentrate m ade a t S ecu rity has been reg u larly sold to and used by fertilizer m a n u fa c tu rers d u rin g the p ast year. E x te n siv e tests w ere m ade to determ ine its suitability in sta n d a rd and special form ulas.
T h e m aterial has been added to fertilizer m ix tu re s up to th e p oint of desired potash concentration in th e final m ix tu re, b u t the am o u n t of such m aterial w hich can be used is lim ited by its free lim e content, w hich is o rd i
n arily well u n d er 10 p e r cent.
A cknow ledgm ent is m ade to th e N o rth A m erican C em ent C orp. an d to th e W e ste rn P re c ip itatio n Co. fo r the d ata used in th e p re p a ra tio n o f this article, an d to the o p eratin g staff o f th e S ecu rity p lan t in th e conduct of th e trials an d tests o f this potash recovery system developed by the W e ste rn P rec ip ita tio n Co.
By W ILLA RD H. ROTHER
M e ta llu rg ist, B u ffa lo F o u n d ry & M a c h in e Co.
B u ffa lo , N . Y .
T h e lo w c o st a n d th e m a n y d e sir a b le p r o p e r tie s o f cast ir o n sire le a d in g an in c r e a sin g n u m b e r o f e n g in e e r s to a d o p t th is m a ter ia l in th e c o n str u c tio n
o f c h e m ic a l e q u ip m e n t
V a cu u m d ru m d ry e r w ith cast iro n casing d e sig n e d for tig h tn e ss a n d re sista n c e to p re s s u re
U T IL IZ IN G C A S T IR O N IN
M
O D E R N m etallurgical m ethods a re p ro d u cin g cast iron o f increased s tre n g th and im proved physical p ro p erties such as high resistance to chem ical corrosion, to p ressu re, and to d efo rm a tio n by heat. T h ese new and im proved ch aracteristics have broadened the fields o f application o f cast iro n in the process in d u stries and, w h ere th is know ledge has been intelligently applied, cost o f p ro d u ctio n and m aintenance has been reduced.P ro p e rtie s govern in g th e resistance to co rro sio n de
pend largely upon the chem ical com position of th e cast iron an d m ay be reg u lated by a lterin g th e com bination of elem ents in a given fo rm u la. C orrosive action d u rin g a given op eratio n m ay also be m aterially influenced by changes in the chem ical process itself. T o obtain the best and m axim um results in an y given case, careful selection and ad ap tatio n o f a p ro p e r com position o f cast iron are th e re fo re essential.
Im p o rta n t facto rs influencing the ra te o f co rro sio n by v ario u s chem icals a re te m p eratu re, co n cen tratio n of th e chem ical, w o rk in g p ressu re, presence of a ir and m oisture, and the fo rm u la and physical p ro p erties of th e iron.
C ast-iro n has m any im p o rta n t applications as a n acid- resistan t m aterial provided p ro p e r consid eratio n is given to th e n a tu re an d the co n cen tratio n of the acid. R e sist
ance to the action o f the w eaker acids is pronounced, p a rticu larly at low o r m o d erate concentrations. T h is re
sistance. w hich is ascribed to th e fo rm atio n o f an iron- carbon-silicon alloy, in general decreases w ith increasing
concentration, te m p eratu re, a n d p re ssu re o f solution.
N o tw ith sta n d in g th e ex trem ely corrosive n a tu re of the stro n g e r acids, p a rtic u la rly acetic, hydrochloric, and n itric acid, cast iron re to rts a re successfully used in the m a n u fa c tu re o f these acids by the action o f co n cen trated su lp h u ric acid on th e ir respective salts. P re se n c e of su l
p h u ric acid com pletely m odifies th e co rro siv e conditions, as this acid has such a g re a t affinity f o r m o istu re, th a t the p a rt of th e r e to rt in d irect co n tact w ith th e acid is protected ag ain st attack. In view o f th e fa c t th a t the o p eratin g te m p e ra tu res a re above the boiling p o in t o f the acid produced, the to p o f the re to rt is in contact w ith v ap o rs only. A s long as su rfa c e condensation is p re vented, no g re a t corrosive action can tak e place an d give trouble.
S u lp h u ric acid and phosphoric acid a re exceptional in th is respect in th a t a n . in term ed iate ra n g e o f co n cen tra
tion ex ists in w hich these acids do not a ttack cast iron.
T h e .fact is w ell know n th a t cast iro n n o rm ally resists the action o f su lp h u ric acid in co n cen tratio n s ra n g in g fro m 70 to 96 p e r c e n t; a t low er co n cen tratio n s it is a t
tacked, th e m ost active ran g e being below 20 p e r c e n t ; fo r su lp h u ric acid above 96 p e r cen t and fo r oleum , g reat care m u st be exercised in the use o f cast iro n because sufficient p re ssu re m ay be created in th e pores of the m etal to cause a fa ilu re in its stru c tu re . I n the sam e ran g e of co n cen tratio n m ix tu re s of n itric and sulphuric acid a re also safely handled in cast-iro n equipm ent. Sul- p h o n ato rs, n itra to rs, co n cen tratin g pans, and acid re-
350 C h e m ic a l & M e ta llu r g ic a l E n g in e e r in g — V o lA O .N o .7
