Treatment method and system for copper smelting complex waste acid

The invention discloses a treatment method and system for copper smelting complex waste acid, and the method comprises the following steps: adding scrap iron into a selenium-removed liquid, and carrying out a replacement reaction to obtain a copper precipitate and a first reaction liquid; carrying out filter pressing treatment on the first reaction post-solution to obtain copper sponge and a copper deposition post-solution; mixing the copper deposition post-solution with beneficiation wastewater to obtain low-copper-content waste acid; a vulcanizing agent is added into the low-copper-content waste acid, then filter pressing treatment is conducted, and copper sulfide slag and liquid obtained after vulcanization and copper removal are obtained; and sulfuric acid and a vulcanizing agent are added into the liquid obtained after vulcanization and copper removal, and arsenic sulfide slag is obtained. According to the method, the selenium-removed liquid is used as the high-copper-content waste acid, so that the proc