Patent ID: 6126840
Filing Date: 2000-10-03
Classification: C02F,Y10S

Abstract:
A process for treating an aqueous effluent comprised of from about 100 ppm to about 10 g/l ferric/ferrous complexes, from about 500 ppm to about 10 g/l silver and water, said process comprising:a) adding to the aqueous effluent a first amount of a chelating agent, the chelating agent being selected from the group consisting of a water-soluble sulfur containing polymer chelating agent or a mixture of the polymer chelating agent and a water soluble non-polymeric sulfur containing compound capable of forming a water insoluble complex with silver, to form a precipitate and a first residual aqueous effluent;b) adding to the first residual aqueous effluent a second amount of the chelating agent to form a precipitate and a second residual aqueous effluent wherein the second amount of the water-soluble sulfur containing polymer chelating agent added to the first residual aqueous effluent is less than the first amount of the water-soluble sulfur containing polymer chelating agent added to the aqueous effluent; andc) separating the precipitate from the second residual aqueous effluent.