LACTIC ACID AND CAS E I N

M i l k is becom ing an im p o rta n t source o f chem­

ical m aterials. M ost o f the development lias been as byproducts o f the d airy industry so as to obtain profits from m aterials that form erly went to waste. P robably II»“ most active and successful organization in this field is the .Sheffield By- P roducts Co. of H o b art and Norwich, New York, a subsidiary o f Sheffield F arm s Co. and, in turn, o f N ational D airy Products Corp. Among the products that are being made in these plants are casein and lactic acid.

The casein is produced by a continuous tech­

nique and mechanism which is am azing in its sim plicity. The machine th a t was specially devel­

oped fo r (be purpose has a capacity o f 25,000 lb. o f skim milk p e r hour, yielding about 2.75 p e r cent casein. Tt occupies a floor area about onc- lialf th a t o f the original machine. H ead room, also has been decreased by a third. The process depends on continuous reaction between m inute quantities o f milk and acid. As a corollary o f continuous reaction has come continuous d raining o f (lie whey and w ashing and pressing of the casein. The process is described in detail in ( ’Item.

iC Mel., Vol. 41, p. 644-46,

The whey which is drained from the curds in the m aking of casein is used in the production of lactic, acid. The ferm entation process em ploy­

ing laoto-bacillus plus a mycoderm is sta rte d in the laboratory, using as a culture pasteurized skim milk. The culture is inoculated in large vessels o f the milk and these in tu rn are used to inoculate raw whey. Lim ing is made to prevent lactic acid concentration from increasing beyond about 1.3 p e r cent. The calcium lactate is p u ri­

fied, concentrated and crystallized to make the I .S.I’, grade. This lactate is dissolved and treated with sulphuric acid to form the lactic acid. The acid is purified by decolorizing with activated carbon to make the 50 per cent w ater white grade. Kor more inform ation about the process see ('hem . <('• .1 let., Vol. ID, p. 480-83.

CMKMRIAL& METALLURGICAL KNGIXKKKIN’G JU N K , 10jO • Pages 427-430

5 After drying the casein Is ground in a disk mill, passed through a gyra­

tory screen and finally packaged ia three-walled paper bags

fo Fermentalion of the w h ey is carried out in 7,000 gallon wooden tanks. The lactose is converled into lactic acid, and subsequent liming neutralizes the acid forming calcium lactate. On completion of fermentation the albuminous matter is coagulated by heating the fermented liquor with live steam

3

4 A tunnel kiln drys the casein. It is steam heated. Trays containing the wet casein enter the dryer stacked on trucks J Skim milk and hydrochloric acid re­

act in a sp ecial mixing device resulting in the formation of "curds and whey".

The curds are then separated from the w h e y in an inclined screw conveyor and p ass on to a similar conveyor in which they are thoroughly w ashed

curds are washed 2 After the casein ,w o.roI1 continuous they are fed into a .|#r con,en, u ^ press where Ihe wc cen, The curd duced to about 50 p, ,Qwer ^ fay a is scraped from the lischarged t0 ,he wooden knife and c

next operation, dryin A d d in

M ilk in

WHEY SCREEN W A S H IN G V , C O N V EY O R

CURD BREAKER

T s t V W a sh W aler

to W a it«

W h e y to tactic Acid

.RO LL G RIN DER

¿ c r e e n

5

C A S E IN PAC KER TRUCK

A G ITA TO R

A N D TR A YS PERFORATED

.✓''M ET AL CHUTE

&

H E A T IN G

C O ILS To

Atm osphere

" >

ST E A M -H EA T ED TU NNEL DRYER

6 0 0 Gol.

STARTER T A N K

Fermented

W hey CRUDE

LIQUO R T A N K STEAM INLET

Alkalinity Acidity

A lbum in Sludge

Sludge

to W aste FILTER

PRESS

Filter A id and I Carbon!

STO RAGE TA N K

I Final I Treatment Evaporating

U.S.P. Lactate Ito Dryer for

\ / Sale FILTER

PRESS Sludge to Alkaline Filtration

1 1 The lactic acid is concentrated to a 50 per cent solution in a double effect and a single effect evaporator

Treating with A d d Y U.S.P. Calcium

Lactate Solution CRYSTALLIZING

V A T

V A C U U M PA N

Lactic Acid P a ck a gin g

W a sh in g s

12

1

“ ,ltS,

^{^ ^} !’ °" "" iU ,"to “

7

8 The calcium lactate liquor is concentrated by vacuum evap­

oration. A double effect evaporator and a single effect are used

O r to Commercial Grade Lactic Acid

Manufacture

W a sh in g s

to Sewer M other Liquor

to Crude Treatment

1 0 Decolorizing material, activated carbon, is separated from

the lactate liquor in a filter press

14

white lactic acid after filtraton

9

stalize the product.

MAKING,

M A T E R I A L S Ur a RAYMOND JO B

R n v m o n o P u l u e r i z e r D i u i s i o n

C O M B U S T I O N E N G I N E E R I N G C O M P A N Y , I N C .

1311 North Branch Street C H I C A G O

S a l e s O f f i c e s in Pr i nci pal Citi es • In Ca na da : Combust i on E n g i n e c r i n s Co r p o r a t i o n , L t d . , M o n t r e a l SINCE 1887

Raymond S C R E E N M ILL

For re d u cin g soft m ate rials to uniform fineness. Built in five sizes fo r c a p a c itie s from a few p o u n d s to several tons per hour.

Raymond L A B O R A T O R Y M IL L

This p ro d u c e s the some character o f m ate rial as la rge co m m e rcia l pulverizers . . . th erefore va lu a b le for a p ilo t mill in running tests or d e v e lo p in g new p rod u cts.

Raymond ROLLER M IL L

w ith

Double Whizzer S e p a r a to r

Y o u can p ro d u ce a variety o f g r a d e s with this one m a ­ chine . . . from 8 0 % minus 100-mesh to 9 9 . 9 % p a ssin g 325-m esh . . . m erely by c h a n g in g the se tting o f the whizzer sp e e d control d ial on the d riv in g transm ission.

G r e a tly incre ase d c a p a c itie s per horse-pow er g ive un­

usually low t o n n a g e costs. H ig h ly e c o n o m ic a l fo r p i g ­ m ent g r in d in g and m any other o peration s.

Raymond IM P M IL L

W hizzer-equipped Flash Drying, op tion al

A c o m p a c t unit for m any sp e cial g r in d in g a p p lic a tio n s.

M a y be used fo r d ryin g, pulverizing and se p a r a tin g in one o p e ratio n . A ls o fo r c o o lin g m aterials to prevent stickiness in g r in d in g . Efficient fo r re m o v in g w ater of crystallization from c o p p e r sulphate in m aking a fine pow ­ dered p ro d u c t for in secticides.

R A Y M O N D e n g in e e r s h a v e sp e c ia liz e d in the d e v e lo p ­ m en t o f p u lv e r iz in g and se p a ­ rating m a c h in er y for m ore than h alf a cen tu ry.

T h e ir long e x p e r ie n c e , plus the ad vantages offered in the la test typ es of eq u ip m en t, p ro ­ v id es the real a n sw e r to m any difficult prob lem s of p rod u c­

tion.

I f you are engaged in the m a n u fa ctu re o f any kind of p o w d er ed m a teria ls, w h ich r e ­ qu ire drying, grinding, c la s s i­

fying . . . w r ite for a R a y ­ m ond C atalog.

CHEMICAL & METALLURGICAL ENGINEERING . J U X B 19.',0 _{4 2 n n}