Research on Sulfur Conversion Behavior in Oxygen Pressure Acid Leaching Process of High Indium Sphalerite

As an important treatment method of processing the sphalerite, the technology of pressure acid leaching has many benefits, such as process flow short, no waste pollution, low production costs, high leaching rate of Zn, and S output in elemental form, which can be sold as a product. This paper takes the high indium sphalerite provided by Kunming Metallurgical Research Institute as the research object. A metallurgical behavior of sulfur conversion process is studied under high temperature and high pressure. The results indicate that the conversion rate of sulfur increases with the increasing liquid-solid ratio, leaching temperature, initial acid concentration and partial oxygen pressure in a certain range. With increasing leaching time, the conversion rate of sulfur increases first and then decreases. Considering all the aspects, the optimum parameters in the condition of conventional electric heating and microwave heating of the process are as follows: liquid-solid ratio 8:1, leaching temperature 423 K, initial acid concentration 120 g/L, partial oxygen pressure 1.0 Mpa, leaching time 90 min. The conversion rate of sulfur reaches 72.00% under the condition of conventional electric heating, 65.74% under the condition of microwave heating.