| abstract |
PROBLEM TO BE SOLVED: To control the sulfuric acid concentration when arsenous acid extracted from arsenic sulphide-containing substances and solidified to dissolve the arsenous acid, thereby preventing a decrease in reaction rate and a catalyst required as a catalyst. Provided is an efficient and low-cost method for producing arsenite, in which copper ions are generated in a system instead of a copper sulfate solution. SOLUTION: A first step of extracting arsenic from an arsenic sulfide-containing substance into an aqueous solution of copper sulfate, cooling a slurry containing an extraction residue and recovering a solid content containing arsenous acid, Add sulfuric acid-containing solution and adjust sulfuric acid concentration to 70g The second step of oxidizing and dissolving trivalent arsenic to pentavalent with high solubility by aeration while controlling to less than / l, and reducing pentavalent arsenic in solid-liquid separated solution to precipitate and recover arsenic acid And a third step. |