Zinc in Secondary Dust of Rotary Hearth Furnace Recovered by Water Leaching and Acid Leaching

In this paper, water leaching and acid leaching were combined to treat secondary dust of a rotary hearth furnace to achieve zinc enrichment. First, the solubles ZnCl₂, KCl, and NaCl in the dust were dissolved into the water solution through water leaching treatment, and separated from the other insoluble components in the dust. Then in order to recover zinc from slag, acid leaching was used to treat the residue. The acid leaching experiment showed that the leaching rate of zinc would increase with the increase of HCl concentration. Finally, in order to recover the zinc, NaOH precipitator was added to the aqueous solution and the acid solution, respectively. The experimental results showed that the content of Zn₅(OH)₈Cl₂ increased first and then decreased with the increase of the precipitator. The total recovery rate of zinc metal can reach 79.46% after the dust is treated by water leaching and acid leaching.