Process Mineralogy and Leaching Toxicity of High-Sulfur Residue from Oxygen Pressure Zinc Leaching

Oxygen pressure zinc leaching can produce many high-sulfur residues (HSR). Due to the lack of in-depth research on process mineralogy and leaching toxicity, it is difficult to treat and utilize the resource of HSR. Taking the HSR of a zinc plant in Inner Mongolia as raw material, the process mineralogy characteristics were studied by means of x-ray fluorescence spectrometer, inductive coupled plasma emission spectrometer, x-ray diffractometer, mineral liberation analyzer, etc. In addition, the leaching toxicity characteristics of HSR was studied by sulfuric acid-nitric acid method, horizontal vibration method and TCLP. The process mineralogy results show that HSR contains S, Fe and Zn, with the highest content of S at 40.03%. The main mineral composition of HSR includes elemental sulfur, pyrite, plumbojarosite, sphalerite, etc. The toxicity test results show that the leaching concentration of Zn, Cd and Pb in HSR is higher than the identification value. HSR has the characteristics of environmental hazard. According to the process mineralogical characteristics, it is recommended to add a screening process to separate the − 45 μ m fraction prior to flotation. This can reduce the adverse effect of fine gangue and plumbojarosite on sulfur flotation.