Removal Mechanism of Mineral Impurities in Molybdenum Concentrate Treatment Process

The removal of impurities in molybdenum concentrate has become a new challenge for enterprises due to the cancellation of pickling. Whether impurity minerals can be converted into soluble ions during roasting is important for the impurity removal by current water washing. In this work, the interaction between various impurity elements in the treatment process of molybdenum concentrate was studied by process simulation experiments combined with X-ray fluorescence (XRF) and X-ray diffraction (XRD), inductively coupled plasma-optical emission spectrometer (ICP-OES), ion chromatography (IC), scanning electron microscope-energy dispersive spectrometry (SEM-EDS), the use of FactSage7.0 modeling and the mineral liberation analyzer (MLA). The results show that most of the impurity elements such as K, Si and Al exist in the form of alkaline minerals with large molecular weight. In the roasting process of molybdenum concentrate, K-containing minerals, such as muscovite and orthoclase, can be transformed into K+, Al3+ and other soluble ions, and then can be removed by water washing. Humidification increased the conversion degree of orthoclase to soluble ions, which was conducive to the removal of impurities by the washing process. The results of MLA microscopic analysis confirmed that impurities such as FeS2, CaSO4, SiO2, and especially FeS2, would form a high density mixture with MoO3 during the high temperature roasting process, and thus reduced the leaching rate of Mo. Therefore, the humidification and control of the molybdenum concentrate is an effective measure to remove impurities.