Patent ID: 6747173
Filing Date: 2004-06-08
Classification: C01F,C07C

Abstract:
A method of preparing of lactic acid and calcium sulphate, comprising:(a) allowing an aqueous solution that contains lactate to react with sulphuric acid at a temperature that is essentially higher than the transition temperature of calcium sulphate dihydrate/ calcium sulphate hemihydrate (CaSO4.2H2O/CaSO4. 0.5 H2O), to form a mixture that contains calcium sulphate hemihydrate and lactic acid, (b) subjecting the mixture from step (a) to at least one recrystallisation step at a temperature that is lower than the transition temperature of calcium sulphate dihydrate/calcium sulphate hemihydrate, to form a precipitate of calcium sulphate dihydrate and an aqueous solution of lactic acid, and (c) separating the precipitate of calcium sulphate dihydrate from the aqueous solution of lactic acid.