METHOD OF PRODUCING CHROME TANNING AGENT Russian patent published in 2024 - IPC C01G37/08 C14C3/06 

FIELD: chemistry.

SUBSTANCE: invention relates to chemical industry, namely to processing of clarified water of slime ponds for production of sodium monochromate to obtain chrome tanning agent. In the method of producing chrome tanning agent, chromium-containing raw material is treated with sulphur dioxide. Clarified water of slime ponds of monochromatic production with content of hexavalent chromium of 2-12 g/l is treated with sulphur dioxide. First, treatment is carried out to pH of solution of 2.5-4.0 at temperature of 5-50 °C. After that, the formed pulp is treated with clarified water until pH of solution is 5-7 with subsequent separation of chromium chromates precipitate. Chromium chromates are then treated with concentrated sulphuric acid and dried to obtain a chromium tanning agent.

EFFECT: improved environmental situation due to reduction of the amount of hexavalent chromium and sodium sulphate in the sludge collector.

1 cl, 3 ex