Thermodynamic Modelling of Molybdenite Roasting in a Multiple-Hearth Furnace

A thermodynamic model was developed to study the roasting of molybdenite ore into molybdenum trioxide in a multiple-hearth furnace roaster. The model was developed using FactSage ™ , a software specializing in thermochemical simulations. The model assumes thermodynamic equilibrium between the solid and gaseous phases on each hearth. The results from the model were compared with operational data obtained from an earlier paper regarding molybdenite conversion at the then Climax Molybdenum Co. roaster in Langeloth, PA, USA. A good correlation has been observed between the conversion of molybdenum-containing species on each hearth and experimental data from the Climax roaster. The developed model also describes the behavior of some of the minor compounds typically present as impurities in molybdenite concentrates.