Pressure aqueous oxidation of molybdenite concentrate with oxygen

The hydrometallurgical processing of molybdenite concentrate was investigated with oxygen as the oxidizing agent at elevated pressures and temperatures. The influencing factors, mechanisms and reaction kinetics of the pressure aqueous oxidation process were studied in detail. The most suitable reaction conditions were: liquid-to-solid ratio of 6:1, an oxygen partial pressure of 1 MPa, a stirring speed of 600 rpm, a particle size < 250 mesh and a temperature of 200 °C. The conversion of molybdenum can reach 99% after 120 min under the most suitable reaction condition. Moreover, it was confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) results that mineral oxidation and the dissolution of molybdenum oxides were the two main steps occurring in sequence during the overall process. The Raman spectroscopic analysis indicated that molybdenum was present in the leached solution in various forms including MoO42 −, H2Mo7O244 −, MoO22 + and Mo36O1128 −. Besides, based on kinetic data, the process is controlled by the chemical reaction.