초록 ▼

There is disclosed a method for recovering silver from photographic processing solution by electrolysis, in which method the cathode potential is set at a potential range wherein a precipitate of silver sulfide is formed in the electrolytic cell. According to the method, intensive silver recovering

There is disclosed a method for recovering silver from photographic processing solution by electrolysis, in which method the cathode potential is set at a potential range wherein a precipitate of silver sulfide is formed in the electrolytic cell. According to the method, intensive silver recovering leading to low concentration of residual silver in the solution is achieved. Structure of electrolytic apparatus enabling easy separation of silver sulfide precipitates is also disclosed. Application of lead peroxide to the material of anode improves the life of the anode. Further advantages of the method are remarkable decreases in COD and iron contents of waste solution.

대표청구항 ▼

A method for recovering silver from a silver-containing photoprocessing waste solution derived from the processing of silver halide color photographic materials and including thiosulfate and iron complex salts, which comprises electrolyzing said waster solution under the condition that the applied v

A method for recovering silver from a silver-containing photoprocessing waste solution derived from the processing of silver halide color photographic materials and including thiosulfate and iron complex salts, which comprises electrolyzing said waster solution under the condition that the applied voltage between a pair of electrodes is set at or higher than the potential at which the generation of sulfide ion takes place, said electrolysis being continued to an extent that a substantial amount of thiosulfate initially present is decomposed and the photoprocessing waste solution is not suitable for reuse as a photoprocessing solution. The method as claimed in claim 1, wherein the precipitate of silver sulfide is formed in an electrolytic cell.