Research advances on reduction and treatment technology of pollutants discharged from zinc smelting

Large amount of wastewater and waste residue containing heavy metals were produced during the traditional zinc smelting process， which leads to the waste of resources and environment pollution. Aiming at the technical bottleneck of reduction and treatment for the pollutants discharged from zinc smelting， systematic researches of fundamental theory and applied technology were investigated. The combined dressing-metallurgy technology of zinc production for emission reduction was developed to realize the efficient separation of iron and zinc and substantial reduction of iron residue from the source of zinc smelting. In addition， new technology for further purification and reuse of Zinc smelting waste water by biological agents was invented to ensure that the concentration of heavy metals in purified water can reach the Emission standard of pollutants for lead and zinc industry （GB25466-2010）. The recycling rate of wastewater increased to 95 %. Moreover， novel technology of sulfidation treatment of heavy-metal-containing sludge for synthetic metal sulfide recovery was explored. The results indicated that more than 85 % of zinc in the sludge was transferred to the metal sulfides and the grade of sulfide ore was 40 %. The research results obtained in this study can provide advanced and suitable technical support for the source reduction of pollutants and the comprehensive management of waste from zinc smelting industry.