Abstract:Address to low recovery rates of gallium in the process of zinc hydrometallurgy by two-stage countercurrent oxygen pressure leaching in a smelter, XRD, SEM-EDS, and ICP-AES were used to analyze the solutions and residues phases at each stage of the process, and the mechanism of the influence of pre-neutralization and zinc powder replacement on the low gallium recovery was investigated. The results show that the co-precipitation of gallium with jarosite or plumbojarosite due to the low acidity during the pre-neutralization of the primary leaching solution is the cause of gallium loss. In the process of zinc powder replacement, gallium cannot be precipitated completely by increasing pH value only by zinc powder. It is suggested that the acidity of the end point of the pre-neutralization is controlled to 6 g/L, the reaction time is one hour, and the reaction temperature is 85 ℃ to avoid gallium loss during the pre-neutralization process. In the replacement stage, the method of first neutralization and then replacement is adopted: 7 g/L high-quality zinc oxide is used for neutralization reaction for one hour, and then 3 g/L zinc powder is added for reaction for one hour at 85 ℃. After optimization, the precipitation rate of gallium can reach 100%.