Process for the detoxification of cyanide-containing aqueous solutions
AssigneeDegussa AG
InventorsNorbert Steiner, Stephen Gos, Frank Ladwig, Manfred Diehl
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Abstract
A process is disclosed for the detoxification of aqueous solutions containing cyanides and/or cyano complexes in the presence of heavy metals which are Mn, Co, Ni, Cu, Cd and Zn, more particularly Cu, by oxidative treatment of the solutions with peroxide compounds at pH values of 8 to 12. Peroxide compounds from the group consisting of alkali metal percarbonates and alkaline earth metal peroxides are used. The peroxide compounds are added to the solutions to be detoxified per se or are formed in situ therein from hydrogen peroxide and other components. Sodium perborate, sodium percarbonate and calcium peroxide are preferred.
Claims20
A process for the detoxification of cyanide-and/or cyano complex-containing wastewater, in the presence of a compound of a heavy metal from the group consisting of Mn, Co, Ni, Cu, Cd and Zn, comprising treating said wastewater with at least one peroxide compound, at least one equivalent of peroxide compound being used per equivalent of cyanide in said wastewater, at a pH value of 8 to 12 and at a temperature between the freezing point of the wastewater and 80.degree. C., wherein one or more peroxide compounds from the group consisting of alkali metal and alkaline earth metal perborates, alkali percarbonates and alkaline earth metal peroxides is used, the peroxide compound being added to said wastewater to be detoxified in solid form or in solution or suspension in water or being formed in situ therein from hydrogen peroxide and a member of the group consisting of the metaborate, the alkali metal and the alkaline earth metal ions.
Dependencies are inferred from the claim text.