Preparation of Molybdenum Ore and Molybdenum Concentrate Reference Materials

Accurate analysis of chemical compositions is vital for exploration and comprehensive utilization of molybdenum minerals. Reference materials can provide criterion and technical support for the chemical composition analysis. At present, there are insufficient reference materials of molybdenum ore and concentrate in series. Most molybdenum ore and concentrate national materials are depleted in China. In order to meet the demand of molybdenum resources exploration, development and trade, three molybdenum ore and 1 molybdenum concentrate reference materials have been prepared, in which the contents of Mo are 0.066%, 0.15%, 0.54% and 50.08%, respectively. Original samples of these reference materials were collected from Henan province which has the largest reserves of molybdenum resource in China. Samples of molybdenum tailing (Mo: 0.02%), molybdenum ore (Mo: 0.09%) and molybdenum concentrate (Mo: 50.0%) were collected. Three molybdenum reference materials were prepared through a weight combination method with corresponding original samples. The molybdenum concentrate reference material was prepared by directly crushing the original sample of molybdenum concentrate. In order to prevent sulfides in molybdenum concentrate from oxidizing, a ball mill was filled with argon during the grinding procedure of the sample. According to the national standard reference materials criterion, a variety of methods at 13 laboratories were applied to determine the chemical compositions. 26 indices including metallogenetic elements (Mo), elements for comprehensive utilization (W, S, Cu, Pb, Zn, Fe, Bi), trace elements for mineral exploration (Ag, As, Cd, Mn, P, Pb, Sb), and principle components in gangue (SiO₂, Al₂O₃, Fe₂O₃, CaO, MgO, Na₂O, K₂O) were determined. These reference materials show good homogeneity, stability, standard value and reasonable uncertainty after corresponding statistical tests. They are a good supplement to improve existing reference materials and have already been certified and approved as national primary Certified Reference Materials (CRMs) by General Administration of Quality Supervision, Inspection and Quarantine of the People′s Republic of China (serial numbers: GBW 07141-GBW 07144), which can be used to give criterion and quality monitoring to analysis in the process of molybdenum minerals exploration, development, beneficiation, metallurgy and trade.