Aiming at the problems of high content of fluorine and chloride in zinc oxide smelting dust, corrosion of anode and cathode plate and poor quality of zinc electrodeposition caused by direct return system, a step process of "acid leaching—defluorination of leaching liquid lime—neutralization of zinc after defluorination" was studied to recover zinc from zinc oxide smelting dust. The results show that under the optimal conditions of leaching temperature of 80 ℃, leaching termination point pH=1.0, liquid volume to solid mass ratio of 4/1 and leaching time of 1 h, the leaching rates of Zn, F and Cl are 96.15%, 95.26% and 97.44%, respectively. When the pH of lime and fluorine-containing soot acid leaching solution is 5.2, the fluorine precipitation rate is 95.17%, while the zinc loss rate is only 1.73%. After fluoride removal, when the liquid is further neutralized with lime to pH=8.0, all zinc can be precipitated, and the mass fraction of zinc in the obtained neutralized slag is about 24%. The removal rates of fluorine and chlorine in the whole process are about 92% and 97%, respectively, the recovery rate of zinc is more than 90%, and the lead and silver can be recovered into the acid leaching residue. The process can realize the efficient removal of harmful elements fluorine and chlorine and the effective recovery of zinc, lead and silver, and has a certain popularization value.

zinc oxide smelting dust  /  zinc  /  electrodeposition  /  leaching  /  fluorine  /  chlorine  /  removal  /  cascade treatment process