An Environmental Approach in Flue Dust Recycling of Copper Flash Smelting Furnace

The flue dust of flash smelting furnace at Sarcheshmeh copper complex includes high concentration of copper (۲۶.۷ wt%). In this research, the effect of various parameters in hydrometallurgical treatment of the flue dust was investigated. In this regard, the leaching efficiency was studied by looking into the key factors that influence the copper dissolution as temperature, solid to liquid ratio, sulfuric acid (H۲SO۴) concentration and the addition of oxidizing agents. Increasing the temperature from ۳۰°C to ۸۰°C improved the copper recovery from ۴۴% to ۵۸%. Decreasing the solid to liquid ratio from ۳۰% to ۱۵% increased the copper recovery from ۵% to ۳۰%, but decreased the copper concentration in the Pregnant Leach Solution (PLS) from ۵۱ g/l to ۱۲.۵ g/L. Increasing the H۲SO۴ concentration from ۵۰ g/l to ۱۹۰ g/l can improve the copper recovery from ۴۸% to ۶۴%. Kinetics studies showed a two-step mechanism was carried out for the duration of ۶۰۰-minute leaching tests at ۴۰°C, ۵۵°C, and ۷۰°C. In the first thirty minutes, the kinetics were controlled by liquid film diffusion, with an activation energy of ۳.۶ kJ/mol. In the second stage (۶۰-۶۰۰ minutes), the mechanism was controlled by the product layer diffusion, with an activation energy of ۲۰.۶ kJ/mol. The efficiency increased from ۴۵% to ۹۷% with the addition of H۲O۲ from ۰ to ۱M. The two-step leaching process combined with the use of an oxidizing agent resulted in the highest leaching yield of ۹۴% efficiency.

کلیدواژه ها:

Flash smelting ، Flue dust ، Kinetics study ، Rate determining step ، Leaching