METHOD OF PROCESSING SOLUTION CONTAINING MIXTURE OF CALCIUM AND MAGNESIUM CHLORIDES (VERSIONS) Russian patent published in 2024 - IPC C01F11/24 C01F5/30 

FIELD: chemical industry.

SUBSTANCE: according to the first version of the method of processing a solution containing a mixture of calcium and magnesium chlorides, initial solution is treated with reagents—gaseous ammonia or its water solution—for precipitation of magnesium ions in the form of magnesium hydroxide or double salt of magnesium-ammonium chloride. Formed precipitate is separated by filtration. Filtrate containing calcium chloride and ammonium chloride is first heated to 60–100 °C to remove ammonia, which is collected in a separate container for reuse, and then heated to evaporation of water and formation of a mixture of solid salts, which are calcined by heating to 350–400 °C to obtain separately solid calcium chloride and solid ammonium chloride, which is collected for reuse. Precipitate after filtration, which is magnesium hydroxide, is heated with ammonium chloride to obtain magnesium chloride and ammonia solution, which is reused. Precipitate after filtration, which is a double salt of magnesium-ammonium chloride, is calcined by heating to 350–400 °C, obtaining separately magnesium chloride and ammonium chloride, which is collected for reuse. According to the second version of the method of processing a solution containing a mixture of calcium and magnesium chlorides, initial solution is treated with a reagent—ammonium sulphate in the form of a solid salt or in the form of a solution—for precipitation of calcium ions in the form of calcium sulphate. Formed precipitate is separated by filtration. Filtrate containing magnesium chloride and ammonium chloride is heated to form a mixture of solid salts, which are then calcined by heating to 350–400 °C to obtain separately solid magnesium chloride and solid ammonium chloride, and the released ammonium chloride is collected for reuse. Precipitate after filtration, which is calcium sulphate, is mixed with a solution of ammonium carbonate taken in amount of 1.01–1.1 of the stoichiometric concentration of which is 1–30 wt.%. Formed calcium carbonate precipitate is separated by filtration, and the filtrate—ammonium sulphate solution—is reused. Calcium carbonate is heated with solid ammonium chloride or with its aqueous solution, obtaining calcium chloride and ammonium carbonate solution, which is reused.

EFFECT: invention enables to separately obtain calcium chloride and magnesium chloride of technical purity.

10 cl, 2 ex