Process for producing high grade molybdenum disulfide powder

A process for producing a high grade molybdenum disulfide powder suitable for use in the formulation of chemicals and as an intermediate for synthesizing high purity molybdenum compounds by which an impure particulated molybdenite concentrate feed material is pulverized and thereafter is subjected to a plurality of purification treatments to effect a progressive extraction of the contaminating mineral constituents entrapped within the molybdenite particles. The purification treatments comprise a wash treatment of the molybdenite concentrate containing up to 10% by weight of hydrocarbon oil employing an aqueous solution forming a slurry which is subjected to successive steps of high shear agitation and low shear agitation to break up the agglomerated molybdenite particles and to effect a release of the mechanically entrapped very fine mineral particles which remain suspended in the aqueous liquid phase. At the completion of the high and low shear treatment, the slurry is transferred to a separator in which the agglomerated molybdenite particles are extracted from the predominant portion of the liquid phase which contains a substantial proportion of the released mineral contaminants. The molybdenite concentrate and the aqueous wash solution are transferred through the plurality of purification treatments in a countercurrent fashion. The resulting agglomerated molybdenite concentrate, free of the contaminants, is then subjected to regular froth flotation to remove any coarse contaminants.