| The silver is applied gradually in every area in recent years, which leads to demand of silver increases year by year. However, very few silver mineral resources exist in the form of independent mineral, most of they are associated with Cu-Pb-Zn minerals. In order to meet the growing needs of people, it becomes more important to reclaim silver from Cu-Pb-Zn minerals and secondary resources. Zinc is one of the primary carrier minerals of silver, but silver could not be reclaimed during zinc smelting or leaching process, it concentrates in zinc leaching slag. The results of flotation recovery silver from zinc leaching slag is very bad in many enterprise for the moment, mostly because of zinc leaching slag is an intermediate product of smelting process. Flotation recovery silver is influenced and restricted by many factors, higher temperature of pulp is one of the main factors. In this paper, the process of flotation recovery silver in high temperature from the slag of zinc hydrometallurgy is used to resolve this problem, at the same time, the mechanism of high temperature recovery process is studied.The pure mineral experiments shows that if the pulp temperature changes in the area from25to70℃, the floating rate of sphalerite is highest when it’s50℃, the flotability is best when the amount of collector is20mg/L, and when pH is2-6the flotability is good, but if pH is higher than8.0the flotability will descends.The neutral zinc leaching slag in this paper comes from Inner Mongolia sing-an copper zinc smelting Co., LTD, the process mineralogy research of the slag shows that it’s composition is complex. In the process of flotation recovery silver in high temperature from the slag of zinc hydrometallurgy, when in conditions of grinding fineness-0.074mm contains94%,pulp temperature is50℃,natural pH, sodium sulfide as the adjustment agent, butyl xanthate and D amine black medicine as collector, PZ as foaming agent, through the closed-circuit process of one rough flotation,two scavengers and four concentratings, qualified concentrate index is gotten: silver3215g/t, a recovery of70.55%, which realizes the recovery of valuable metal silver from neutral zinc leaching slag.The mechanism research shows that the results of electron microscopic and adsorption when sphalerite reacts with agents in different temperature verify the warming flotation phenomenon of pure sphalerite, they also similar to the flotation rule of actual mineral temperature conditions of neutral zinc leaching slag Through deriving the data, the dynamic formula of sphalerite warming flotation process is:In ε=5.10133-233.14/T, which is consistent with experiment results. The study of thermodynamics of Sphalerite surface oxidation finds that when the temperature of solution is50℃, the needed potential is lower than normal temperature when Sphalerite is oxidized to elemental sulfur or sulfate ions. It shows Sphalerite is oxidized easier in higher temperature and excessive oxidation will make flotability poor, so when the temperature increases a little, it is helpful to quicken the Sphalerite surface oxidized to elemental sulfur and the flotability will become better. Infrared spectral analysis finds that in the temperature of60℃the character absorption peak of sphalerite reacts with butyl xanthate is strongest, it will make new substances when the temperature rise to50℃or higher. The thermodynamic analysis of silver minerals react with agents shows the change of temperature has little impact on flotation recovery natural silver. |
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