METHOD OF PRODUCING SODA ASH AND GYPSUM Russian patent published in 2019 - IPC C01D7/18 C01F11/46 

FIELD: chemistry.

SUBSTANCE: invention relates to inorganic chemistry and can be used in chemical industry. For production of soda ash into produced in production of soda in ammonium method filtered distillate liquid containing sodium chloride, calcium carbonate is added in amount of 50–100 kg per one ton of soda and sulfuric acid until the obtained mixture reaches pH 6–7. Method then includes adding sodium sulphate solution with concentration of 23–25 % at temperature of 97 °C and at a ratio of sodium sulphate to calcium chloride of 1:(1.26–1.3), the obtained calcium sulphate in sodium chloride solution is treated with lime to pH 10.8–11.3, and separated on a filter. Calcium sulphate precipitate is washed with water and gypsum is obtained from it. Soda is obtained from sodium chloride solution.

EFFECT: ensuring absence of production wastes and reduction of energy resources consumption during production of gypsum and soda ash.

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