Treatment method of waste acid generated in copper smelting

摘要

PROBLEM TO BE SOLVED: To provide a method of treating waste acid generated in copper smelting which reduces work necessary for maintenance inspection, including monitoring of a dehydration installation and replacement of a filter cloth, in individual dehydration steps for a slurry rich in sulfide precipitates obtained in primary and secondary steps and is efficient and excellent in economy.SOLUTION: A method of treating waste acid generated in copper smelting includes: a primary sulfurization step of mixing waste acid with a sulfurizing agent to sulfurize heavy metals and separating the resultant mixture into a primary slurry containing sulfide precipitation and a primary clear liquid; a gypsum production step of mixing the primary clear liquid with a neutralizer to convert sulfuric acid to gypsum and solid/liquid-separating the resultant mixture to obtain a gypsum final liquid; and a secondary sulfurization step of mixing the gypsum final liquid with a sulfurizing agent to sulfurize heavy metals and separating the resultant mixture into a secondary slurry containing sulfide precipitation and a secondary clear liquid. In the secondary sulfurization step, the secondary slurry after separation of the secondary clear liquid is returned to the primary sulfurization step to mix with waste acid.