METHOD OF ISOLATION OF POTASSIUM-SODIUM TARTRATE FROM AQUEOUS SOLUTIONS Russian patent published in 1995 - IPC

FIELD: chemical technology. SUBSTANCE: process is carried out from aqueous solutions of product indicated which were evaporated in evaporator supplied with steam-and-water jacket and mixer under vacuum at residual pressure 50-60 kPa and 90 ± 5 C for 6-10 hr up to density of solution 1.44-1.46 g/cm³. After cooling solution up to 20 ± 5 C crystallization is carried out in crystallizer supplied with water jacket and mixer for 6-13 hr followed by separation of salt crystals from primary mother liquid. The latter is evaporated again, crystallized and salt crystals were separated obtaining the secondary mother liquid. The latter is subjected for similar processing obtaining the third mother liquid after separation of tartaric acid salt crystals. The tertiary mother liquid is treated further with concentrated nitric, hydrochloric, sulfuric, perchloric and acetic acid at the molar ratio acid and salt containing in mother liquid 1:(1.0-1.2) followed by keeping reaction mixture at batch stirring and the room temperature for 1-3 hr. Formed precipitate is separated and treated successively with water, NaOH up to pH 8.5-10.0 which then evaporated, crystallized and crystals of the end salt were separated. Method ensures additional yield of deficient reagent from tertiary mother liquid (220 g from 500 ml). EFFECT: increased yield, simplified process. 1 tbl