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INTERNATIONAL
Cheaper Lactic Acid Ahead? Bowmans Chemicals purifies iacfic acid extraction, simplifies regular process
by^ solvent
p i r e d ) on using isopropyl ether to ex tract lactic acid. Du Pont's mum on its processing now. American Maize Products says it has studied extraction processes, but has found that they w o u l d be more expensive to operate thstn its present vacuum-concentrating method. Clinton Corn Processing also ha^s studied extraction processes; it fo*ind that isopropyl ether was the best solvent fo>r the purpose. In Bowmans' process, dilute calcium lactate from fermentation, after removal of bacterial protein, is acidified and cal c i u m removed a s the sulfate. The dilute luetic acid is then decolorized in
C H E A P E R lactic acid may be around the corner. The potential savings would come from a simplified, con tinuous purification process developed by the British firm, Bowmans Chemi cals. Solvent extraction is the key. The new technique, Bowmans says, shrinks the conventional purification process, which involves coagulation, decolorization, crystallization, acidifica tion, removal of heavy metals, and evaporation under vacuum, a number of these stages being repeated. Purifying lactic acid by solvent ex traction is not new to U. S. firms, how ever. Du Pont has a patent ( n o w ex
Lactic Acid - Purified by Solvent Extraction
Dilute Calcium
Refinery Wastes Mastered
Solvent -Extraction
Fermentation
Columns
Acidification
Τ Τ Filtration
" Waste
I
Sludge I
Solvent Stripping Columns
Desulfurîzation Filtration
Vacuum EvaDoration
Evaporation
Evaporation
Decolorizer
Technical Lactic Acid
Resin Column
'>*7" Edible Lactic Acid
activated carbon columns which are regenerated in sequence. (Bowmans Chemicals has patented this and other features of the process.) Residual calcium, amino acids» and traces of heavy metals are next removed from the dilute acid by percolation through ion exchange resin, which i s regenerated in the usual way. The purified acid is then evaporated under vacuum to high concentration, a n d the product is extracted b y an organic sol vent in countercurrent flow. Re-ex traction by distilled water in countercurrent flow follows. The stripped sol vent is recirculated to the extraction tower. The resulting pure aqueous extract i s given a final decolorization a n d ion exchange treatment. It is then ready for sale or for further evaporation t o the strongest grade. Plastics would be a big market for such high-purity lactic acid. But Clin ton says the plastics industry would want the material at 5 cents a pound— a price too low to achieve by solvent extraction, Clinton claims. D u Pont says that 15 to 20 cents a pound would be suitable to the plastics industry. This price level shouldn't rule out solvent extraction, D u Pont feels.
Pure Lactic Acid
Evaporation
•IEdible Lactic Acid
Cities Service Oil Co., Ltd., believes it has whipped water pollution problems at its n e w Trafalgar refinery, just put on stream at Bronte, Ont. A super waste treatment plant there uses biological oxidation, ozone treatment, and filtration to clean up water in a variety of refinery wastes. Product water, says Cities Service, is of drinking purity. Here's how the waste treatment plant works: Refinery wastes flow through underground pipes to a large basin. The waste water is allowed to stand long enough so that runaway oil can float to the top and heavy material settle tj the bottom. Mechanical racks then skim the oil off the top and scrape the sludge off the bottom. The oil goes back to the refinery for processing; trie sludge is p u m p e d to a diickener, where the residue is dried and hauled away. The oil- and sludge-free water goes to a large pit called the equalization basin. Here, acids and bases are partially diluted and neutralized, and suspended solids can be uniformly dispersed throughout the basin. The (Continued JUNE
15,
on page 1959
112) C&EN
77
(Situations Vt'unt«?«l, GoiitiiauccS) RKSKAHCH SlPKHVl^OU: Organic chemist P l i . I ) . . t « i y***ii> m«iu>triî*I p\pert«'iire nid «tir«*> n'spon-ible p o s i t i o n . H . A . . ace 29. B o x 603-J-6. C & K. N \ . E a s t on. F»a. ADVERTISING. SALKS PROMOTION: C h a l l e n g e M.»*i«ht l»y a m b i t i o u s ycuune m i l i u m . A s s t . a
