Recovery of molybdenum from spent lubricant

Abstract

The recovery of Mo from spent lubricant by applying carbothermic reduction was investigated. The carbothermic reduction of CaCO3-MoS 2-C, CaCO3-MoS2-Fe2O3-C and the spent lubricant-CaCO3-Fe3O4-C mixtures at 1073 K, 1173 K, 1273 K, 1373 K and 1473 K were carried out to investigate the reduction mechanism of MoS2 under various conditions. The reduction process was anlayzed by using quadruple mass spectroscopy (QMS) analysis, differential thermal analysis (DTA) and X-ray diffraction (XRD) analysis. Based on the investigated reaction mechanism, the carbothermic reduction of the spent lubricant-CaCO3- Fe3O4-C mixtures at 1 773 K was carried out to confirm the feasibility of the Mo recovery from the spent lubricant. Mo in the spent lubricant was found to be fully recovered as molten Fe-Mo alloy by the reaction, MoS2(s) + 2CaO(s) + 2C(s) → 2CaS(s) + 2CO(g) + Mo. The recovered Fe-Mo alloy contained about 40 mass% Mo and 4.3 mass% C. Thus, Mo recovery from the spent lubricant by carbothermic molten reduction is promising. © 2012 ISIJ.