Metallgesellschaft Aktiengesellschaft

Frantisek Hotek

Jiri Pendl

Vaclav Cerny

Ulrich Heinrich Sander

Rudolf Boensch

Klaus Hohmann

Michael Karl Eichelsbacher

Juergen Kuhn

Bernd Ahlers

Jurgen Kuhn

Citric acid and/or the salts thereof are produced from a raw material containing carbohydrates. An aqueous solution of the raw material is converted into a first solution containing citric acid by means of fermentation, and from the first solution a second solution containing citric acid is obtained by means of a cell separation. The second solution is subjected to a protein precipitation at temperatures of 2 to 70.degree. C., and protein is separated by filtration. From the filtration, a third solution containing citric acid is obtained, and the same is passed through a first anion exchanger. The solution containing citric acid, which is discharged from the first anion exchanger, is passed through a second anion exchanger, which is selectively charged with citric acid. The second anion exchanger charged with citric acid is eluted with hydroxide solution or water, and there is thus obtained a fourth solution, in which citrate or citric acid is dissolved. Water is at least partly removed from the fourth solution.

Process for producing citric acid and/or citrates

A process is disclosed for preparing an organic acid and/or its salts from a solution obtained through fermentation. In this process, a pure carbohydrate-containing raw material is used. The acid-containing solution prepared by means of fermentation is supplied to a cell separation, and the acid-containing permeate is supplied to a protein precipitation, where it is mixed with a silicon-containing precipitant at temperatures between 2.degree. and 70.degree. C. The solution thus obtained is supplied to a protein separation, and the acid-containing permeate is concentrated and then supplied to a single- or multi-stage crystallization or a granulation.

Process of preparing an organic acid

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Petrohrad, Czechoslovakia

Frantisek Hotek