METHOD FOR DECONTAMINATION OF AQUEOUS SOLUTIONS CONTAINING COMPOUNDS OF HEXAVALENT CHROME Russian patent published in 2019 - IPC C02F9/04 C02F1/70 C01G37/14 C02F101/22 C02F103/16 

FIELD: technological processes; processing and recycling of wastes.

SUBSTANCE: invention can be used in the field of processing liquid chromium-containing wastes, as well as for neutralizing solutions containing hexavalent chromium compounds in the chemical treatment of metals. Method includes the addition of a reducing agent – hydrazine, mixing and filtering the precipitated precipitate. Process of recovery of hexavalent chromium is carried out in two stages, first with the amount of hydrazine 50–70 % of stoichiometry and then by adding metallic iron in an acidic medium, then a solution of yellow blood salt and nickel nitrate is added, the solution is neutralized to a pH of 8.0–10.0 and the precipitated trivalent chromium hydroxide is filtered. After filtering the resulting pulp, the solution can be drained into the water area.

EFFECT: method provides an environmentally safe and inexpensive technology for the disposal of chromium-containing wastes containing radionuclides, subject to the norms of discharge of treated effluents into fisheries; resulting chromium hydroxide can be used as an intermediate for the preparation of other chromium compounds.

1 cl, 2 ex