| 摘要 |
PROBLEM TO BE SOLVED: To reduce the quantity of arsenic to be disposed of by decreasing arsenic content in a waste acid in the treatment of the waste acid discharged from processes of the chlorination of arsenious acid and the distillation and purification of arsenic trichloride and containing large quantity of hydrochloric acid and arsenic trichloride at the time of producing metal arsenic by chlorinating arsenious acid with hydrogen chloride, purifying the formed arsenic trichloride and reducing it with hydrogen under heating. SOLUTION: Arsenious acid is obtained by adding a dil. waste acid reduced in hydrochloric acid content into the concd. waste acid containing large quantity of arsenic trichloride and hydrochloric acid to hydrolyze arsenic trichloride and is separated to be reused. The dil. waste acid is prepared by bringing the waste acid residual liquid after arsenic trichloride is hydrolyzed by adding the dil. waste acid to the concd. waste acid and arsenious acid is separated, into contact with water through an ion exchange membrane and transferring the hydrochloric acid portion in the waste acid residual liquid into water. |
