Features and mechanisms of self-sintering of molybdenite during oxidative roasting
(1. School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China;
2. National Engineering Laboratory for High Efficiency Recovery of Refractory Nonferrous Metals, Changsha 410083, China)
2. National Engineering Laboratory for High Efficiency Recovery of Refractory Nonferrous Metals, Changsha 410083, China)
Abstract: Roasting experiments were carried out with pure reagents as raw materials. The self-sintering behaviors of molybdenite (MoS2) during oxidation were investigated by thermodynamic calculation, XRD, SEM-EDS and high-temperature in situ analysis. The results indicate that the desulfurization efficiency of MoS2 pellet decreases with the increase of roasting temperature from 600 to 700 °C, owing to the expansion of sintered area. At the very beginning of roasting, sintered layer can be rapidly formed and cover the pellet surface on the windward side, and meanwhile, MoO2 and Mo4O11 intensively appear and constitute the sintered layer together with MoO3. Moreover, it is proven that MoO3-rich products containing low-valence molybdenum oxides have low melting points, thus easy to be melted during the occurrence of exothermic reaction between MoS2 and O2, which leads to the sintering of materials.
Key words: molybdenite; oxidative roasting; sintering; distribution characteristic; mechanism