METHOD OF FREE CYANIDE REGENERATION FROM WATERS CONTAINING THIOCYANATES AND HEAVY METALS, BY SELECTIVE OXIDATION Russian patent published in 2018 - IPC C02F1/72 C02F1/62 C22B3/44 

FIELD: chemistry.

SUBSTANCE: invention relates to methods for free cyanide regenerating from waters containing thiocyanates, cyanides and heavy metals. Method of free cyanide regenerating from waters containing thiocyanates and heavy metals includes selective oxidation in acid media, trapping prussic acid from the waste gases to an alkaline absorber, alkalizing the waters after their oxidative treatment. At that, part of the waters after oxidative treatment or hydrocyanic acid purging is directed to mixing with the source waters in such a proportion that the mixture pH is optimal for precipitation and removal of heavy metals. For waters oxidizing treatment reagents or physicochemical processes are used, which are capable of selectively oxidizing thiocyanates to hydrocyanic acid with pH of less than 6.0, preferably less than 2.5, at that the hydrocyanic acid is oxidized to an insignificant degree. In addition to thiocyanates, sent to treatment waters may contain cyanides.

EFFECT: technical result consists in reducing the consumption of reagents (acid) while maintaining high rates of cyanide removal from water.

3 cl, 1 dwg, 3 tbl, 2 ex