Selective flotation of scheelite from calcite using a novel self-assembled collector. (1st September 2021) - Wang, Cong
Graphical abstract: Highlights: Pb-BHA-NaOL first used to separate scheelite from calcite without any depressants. Over 85% of scheelite achieved from binary mixed minerals at pH 9 using Pb-BHA-NaOL. The positively charged species in Pb-BHA-NaOL have more adsorption on scheelite. Pb-BHA-NaOL has a stronger chemical interaction with O sites on scheelite than on calcite. Interaction with O sites is better than with Ca sites to separate calcium minerals. Abstract: Both being Ca-bearing minerals, scheelite and calcite cannot be well separated by froth flotation due to their similar surface properties. To date, there is no report that scheelite and calcite can be well separated using collectors alone (including traditional NaOL and selective Pb-BHA complexes). Therefore, in this study, Pb(NO3 )2, benzohydroxamic acid, and sodium oleate with specific combination (Pb-BHA-NaOL) were firstly used to form a novel collector to selectively separate scheelite and calcite. The flotation results of single and binary mixed minerals showed that the mixture of Pb, BHA and NaOL (molar ratio 6:6:1) exhibited excellent separation selectivity for scheelite and calcite at pH 9.0. Zeta potential measurements indicated that the dominant species of Pb-BHA-NaOL were positively charged and had stronger adsorption on negatively charged scheelite surfaces. Infrared spectroscopy and X-ray photoelectron spectroscopy further showed that Pb-BHA-NaOL had strong chemical interaction with Ca sites in the form of Pb(OH)-BHA-OL −, especially with O sites in the form of Pb-BHA + on scheelite, but had no interaction with O sites on calcite. Therefore, the novel collector proposed in this work can provide a meaningful guide for the design of other novel collectors and have potential application prospects in scheelite flotation.