Leaching kinetics of calcification roasting calcinate from multimetallic sulfide copper concentrate containing high content of lead and iron

• Complex multimetallic sulfide copper ore was roasted with the aid of calcium oxide.
• Sulfur retention efficiency was 97.77% during calcification.
• Leaching kinetics model is derived on experimental data obtained in this work.

The multimetallic sulfide copper ore containing large amounts of lead and iron was roasted in air atmosphere in the presence of calcium oxide, and the calcinate obtained was leached in sulfuric acid solution to extract copper. Characterization of the raw materials, calcinates and leach residues was conducted by using XRD and SEM/EDS analysis. The calcification mechanism of the complex ore was studied. The effects of temperature, stirring speed, liquid/solid ratio and sulfuric acid concentration on the kinetics and mechanism of copper dissolution from the calcinate were also investigated. Results of experiments show that sulfur retention efficiency in the calcinate achieves 97.77%, and that increasing both reaction temperature and acid concentration are capable of resulting in the increase of dissolution rate of copper. Leaching kinetics follows the un-reacted shrinking core model with a rate controlling step by diffusion through the solid product layer and the corresponding apparent activation energy is calculated as 19.21 kJ/mol, and consequently the rate of the dissolution of copper on aspect of H2SO4 concentration, liquid/solid ratio, and stirring speed can be expressed as 1+2(1-x)-31-x2/3=6.44×10-4×CA1.72×L/S1.25×ω0.94exp(-2310/T)t.

Figure optionsDownload as PowerPoint slide