On The Inverstigation Of Hot-Press Acid Leaching Treament To Copper Pyrites Residues

Desulfuration is an unavoidable and critical issue in heavy nonferrous metallurgy. On the review of current research and technology progresses, a technology to extract sulfur from the residue of copper pyrites leached by acid was studied in this work.Based on the analysis of real process operation and investigation of lab scale experiments, the work aims to develop a sulfur extraction process for residue of copper pyrites with easy to operate, safe in precedure, effective on technique.In the work, different sulfur extraction methods including high temperature filtration, floatation, dimethylbenzene, ammonium sulfide were compared. Taking the advantage and disadvantage, process safety and environmental consideration, and economical efficiency of these techniques as well as the components of the residue into account, the ammonium sulfide solvent method was chosen for treating such a residue according to the comparative experiments and analysis.The work aimed to improve the leaching yield of sulfur, find out the character of kinetics of leaching process, according to the shrinking core model and experimental data. The result showed that the process by utilizing the technique is a diffusion-through-layer-reaction-control procedure. Therefore, decreasing the particle size and increasing the leaching temperature will benefit to the reaction rate.The results show that the ammonium sulfide solvent method can achieve about 96% leaching efficiency extraction at the conditions of ammonium sulfide concentration 2.0mol/L, temperature 30℃, reaction time 60 min, ratio of ammonium sulfide to solid residue 8 : 1 when the method is applied. The thermal decomposition can reach 94% at temperature of 90℃, and duration of thermal decomposition 90 min. The purity of sulfur produced by the method can achieve 98%, which meets the standard of sulfur for industrial use.The process developed in this work has advantages with easy to operate, mild in reaction conditions, low cost, more environmental friendly, and higher sulfur extraction yield.