Leaching of copper(I) sulphide by sulphuric acid solution with addition of sodium nitrate

Finely grained samples of copper(I) sulphide were leached by H2SO4 solution with added NaNO3. The occurrence probability of chemical reactions was analysed based on literature data and products which were formed during the process and the overall leaching reaction was defined. The effect of temperature, concentration of NaNO3 and H2SO4, stirring speed, phase ratio and time, on the leaching degree of copper was studied. The quantity of copper dissolved increases with growth of the values of all the parameters. Kinetic analysis shows that the leaching mechanism is very complex. By using appropriate mathematical kinetic models, it is found that the leaching rate is chemically controlled. It was concluded that the leaching reaction is first order with respect to the concentration of NaNO3 and second order with respect to the concentration of H2SO4.