Patent ID: 6534678
Filing Date: 2003-03-18
Classification: C07C

Abstract:
A process of producing tartaric acid from a raw material whose dry matter comprises at least 5 wt-% potassium hydrogentartrate (KHT), whereina) in a first reaction stage the raw material is mixed with aqueous potassium hydroxide solution, and KHT is virtually completely reacted to form dipotassium tartrate (DKT), b) from the first reaction stage there is withdrawn a first aqueous solution containing DKT, impurities are removed, and in a precipitation stage the first solution is mixed with added acid at a pH value of 2.0 to 5.0, and a suspension containing crystallized KHT is produced, c) crystallized KHT is separated from the suspension, washed with water, and there is produced a second aqueous solution saturated with KHT for at least 80 wt-%, and d) from the second aqueous solution potassium is removed, an aqueous tartaric acid solution is produced, and from the tartaric acid solution water is at least partly removed.