Patent ID: 7601200

Claim:
A method of separation/purification for high-purity silver chloride from a refining intermediate containing a sparingly soluble silver compound and one or more species of impurity elements, comprising: (1) a leaching step in which the refining intermediate is leached with an aqueous sulfite solution to extract silver with the solution and thereby form a silver-containing liquid resulting from the leaching and an insoluble residue, (2) a silver chloride generation step in which the liquid resulting from the leaching is neutralized and acidified to precipitate silver chloride and thereby form the silver chloride and a mother liquor, and (3) a silver chloride purification step in which the silver chloride is oxidized in an aqueous acidic solution by adding an oxidizing agent to dissolve and separate impurity elements and thereby form purified silver chloride and a solution containing the impurity elements wherein the oxidation treatment is carried out at an oxidation-reduction potential of 800 to 1200 mV, determined using a silver/silver chloride reference electrode, in the silver chloride purification step.