Reduction of molybdenite with carbon in the presence of lime

The thermodynamics of the MoS2-C-CaO system has been studied in order to understand the carbothermic reduction of molybdenite in the presence of CaO. Kinetic studies were also conducted with mixtures of MoS2+C+CaO in the temperature range of 900 °C 1200 °C. The reduction of MoS2 with carbon in the presence of lime proceeds through the direct oxidation of MoS2 by CaO to form intermediate molybdenum oxidized species, MoO2 and CaMoO4, which subsequently undergo reduction by CO to yield mixtures of Mo, Mo2C, and CaS. Complete conversion of MoS2 can be obtained at 1200 °C in less than 20 minutes for molar concentrations of MoS2:C:CaO=1:2:2. The kinetic model ln (1−X)=kt was used to determine the rate constants. The activation energy found for the temperature range studied was 218.8 kJ/mol.