Separation of talc and molybdenite: challenges and opportunities

Abstract

Abstract Talc is one of the most problematic hydrophobic gangue minerals that occur in sulfide ores such as molybdenite and Pt-bearing nickel sulfide ores. Owing to its strong natural hydrophobicity, talc can easily float into the sulfide mineral concentrates, which not only lowers concentrate grade but also adversely affects subsequent smelting. Over the past several decades, many studies have been carried out to separate the hydrophobic gangue mineral talc from molybdenite by froth flotation and other techniques. However, the selective and efficient removal of talc from molybdenite concentrates remains a challenging issue, and the underlying mechanisms of depression are poorly understood. To better understand the flotation and depression behaviors of talc and molybdenite, a fundamental understanding of the surface properties, such as surface charge, wettability and their alteration, is required. Recently, significant progress in understanding the surface chemistry of talc and molybdenite has been made and novel depressants have been developed. In the current review, these recent advances are systematically discussed, together with a discussion of conventional practices and reagent systems for the molybdenite-talc separation. The remaining challenges and future directions for the molybdenite-talc separation are also presented.