Successive gas-solid reaction model for the hydrogen reduction of cuprous sulfide in the presence of lime

As an alternative to conventional smelting processes for producing metals from sulfide ores, which suffer from SO₂ emission problems, direct reduction in the presence of lime has in recent years attracted much attention. In this work, a mathematical model of successive gas-solid reactions in a porous pellet has been applied to the hydrogen reduction of cuprous sulfide (Cu₂S) in the presence of lime. The model has been formulated by incorporating the intrinsic kinetics of the individual reactions obtained from separate experiments, and compared with the experimental results on the hydrogen reduction of chalcocite mixed with lime particles. The model predictions were in good agreement with experimental measurements of the overall rate of reaction and the degree of sulfur fixation over a wide range of experimental conditions. The mathematical model not only can predict the performance of a given system but also enables one to design the optimum pellet properties and reaction conditions in terms of the reaction rate and sulfur fixation. Formerly Graduate Student in the Department of Metallurgy and Metallurgical Engineering, University of Utah.