An investigation into the precipitation of copper sulfide from acidic sulfate solutions

摘要

Due to the local and global supersaturation of metal sulfides in aqueous solutions, the industrial metal sulfurization processes using soluble sulfur resources (Na2S/Na2S2O3/(NH4)(2)S/H2S) and elemental sulfur have insurmountable defects, including the unfilterable fine precipitates, weak chemical selectivity, high reagent toxicity, and generation of soluble polysulfides. In order to develop a cleaner and green sulfurization method, a surface/heterogeneous sulfurization system using wetted sulfur particles and sulfur dioxide was investigated through single-factor experiments and reaction mechanism tests. The results of disproportionation tests indicated that reaction parameters, such as temperature, powder contact angle, SO2 pressure and molar ratio of Cu-to-Sulfur, significantly affected the reaction efficiency. The reaction is mixed controlled by the temperature and powder contact angle. During the disproportionation-sulfurization process, the total reaction rate for the generation of HS- ions is dependent upon: the liquid diffusion of SO2 absorption, the powder contact angle of wetted sulfur particles, and the nucleophilic reaction between SO3H- with sulfur. Meanwhile, the total reaction is a shrinking nuclear reaction which the particles sizes continuously increasing after the metal sulfides formed.