FIELD: chemical technology; processing of exhausted concentrated chromic electrolyte and washing water or sewage. SUBSTANCE: exhausted solutions comprising compounds of hexavalent chromium are reduced. Product being prepared by interaction of acid solutions of etching of ferrous metals with waste of machining are used as reduction agent. Thus obtained ions of trivalent chromium and trivalent ferrum are precipitated, compounds comprising phosphate ions being used. The process takes place at pH 6.0-8.0 at stoichiometric ratio of phosphate anion and trivalent cations (chromium and ferrum). Thus prepared precipitate is separated of solution and is used as pigment paste. Exhausted solutions of degreasing bath may be used as compound comprising phosphate ion. EFFECT: improved efficiency of the method. 2 cl
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