A New Process Of Treating Fe2r Residue By Microwave Sulfation Roasting And Immersion

Due to the good performance of precipitation, filtration and washing, the jarosite process has been widely used to remove Fe from leach liquor of zinc hydrometallurgy. The long-term stockpiling of jarosite with a large quantity and a high heavy metals content is a big threat to the environment.In order to eliminate the harm of jarosite and to recover valuable metals, a new process to dispose of jarosite by sulfuric acid roasting using microwave, water leaching and geothite process for iron removing is presented in this paper. Firstly, the jarosite blended with H2SO4 was roasted by microwave. Then the roasted residue was subjected to water leaching, after liquid-solid separation, the leach liquor containing Fe, Zn, In, Cu, Ag, Cd and Pb-rich leach residue could be attained. Finally, after iron-removing by geothite process, the leach liquor could be sent to zinc hydrometallurgy system for recovering valuable metals Zn, In, Cu, Ag, Cd, etc. And the leach residue could be used for additive of lead metallurgy.According to the experimental results of sulfuric roasting and water leaching, the optimized experimental conditions were determined as: addition amount of H2SO4 36%, roasting temperature 250℃, roasting time 30min, temperature of water leaching 50℃, time of water leaching 1h, stirring rate 300r/min and liquid-solid ratio 4:1. Under these optimum conditions, the leaching ratio of Fe, Zn, In, Cu, Ag and Cd could reach 89.4%,80.7%,85.1%,90.7%,61.3% and 48.8% respectively, and the main composition in the leach residue was PbSO4.The results of geothite process showed that the optimized conditions for iron-removing were determined as:pH 3.0, dropping rate of leach liquor 3mL/5min, addition amount of seed crystal 20g/L. Under these conditions, a iron-removing ratio as high as 99.3% could be attained, and the loss of other valuable metals was low. The content of Fe in residue is 47.08%.