AbstractThe rate of dissolution of synthetic cupric sulphide (CuS) which is the analogue of the naturally occurring sulphide mineral covellite, in sulphuric acid solutions of concentration range 5 × 10−3to 3 mole/l over the temperature range 20–65°c at atmospheric pressure was studied.Thermodynamic considerations suggested that the primary reaction taking place during the leaching is: CuS+1/2O2+ H2SO4→ CuSO4+ S+H2O.It is proposed that up to an initial sulphuric acid concentration of 1 mole/l, the reaction rate is controlled by the diffusion of H+ions through the sulphur film to the CuS/S interface. For higher sulphuric acid concentrations the oxygen dissolved in the acid decreases and the rate‐determining step is believed to be diffusion of dissolved oxygen through the sulphur film to the CuS/S interface. A parabolic model is suggested for the dissolution reaction, and this model is supported by the experimental data.The activation energy for the dissolution reaction was found to be 8000±2000 cal/mole and this was independent of the H+concentration and hence the nature of the diffusi