Research Progress with Scheelite Flotation Reagents: A Review

With the depletion of easily mined and separated wolframite, scheelite has become the primary source of tungsten. Flotation is the primary technique used to enrich scheelite. However, flotation separation of scheelite from calcium-bearing gangue minerals, such as calcite and fluorite, has always been challenging due to their similar surface properties. To date, various flotation reagents and related mechanisms have been proposed for scheelite, which have attracted considerable attention. This paper reviews the scheelite flotation reagents, including collectors and regulators, and introduces recent research progress on the mechanisms for the interactions between the flotation reagents and mineral surfaces. The advantages and limitations of different flotation reagents are discussed. Inorganic or organic inhibitors in combination with fatty acids, chelate collectors, and cationic collectors are commonly used to separate scheelite from calcium-bearing gangue. Flotation differences between the scheelite and calcium-bearing minerals can be explained by variations in the electrical charges and steric hindrance at the mineral surfaces. In the future, fatty acid collectors will be still the main collectors used in scheelite flotation due to their low cost and strong collecting ability, and new collectors with high selectivity (such as metal complex collectors, new chelate collectors, new environmental collectors) will become a new research hotspot in the future due to their good selectivity.