Study on the mechanism of different metal ions synergistic with alkali etching treatment in the flotation of lepidolite and feldspar

Abstract

The two minerals were separated through alkali etching on the surface of lepidolite and feldspar, in conjunction with metal ion activation flotation. The activation of calcium (Ca2+) ion, magnesium (Mg2+) ion, copper (Cu2+) ion, and ferric (Fe3+) ion under alkali and non-alkali corrosion conditions was investigated, respectively. Micro-flotation experiments demonstrate that Ca2+ and Mg2+ can selectively recover lepidolite but not feldspar when the pH is above 6.5 during alkali etching. The activation of Cu2+ and Fe3+ flotation is not selective and can activate lepidolite and feldspar to some extent, irrespective of alkali etching. Through the valence bond theory, the selectivity of lepidolite and feldspar to dissolve and break bonds under alkali etching in a solution system was calculated. The adsorption differences and mechanisms of four types of metal ions were analyzed using solution chemistry, particle size analysis, and X-ray photoelectron spectroscopy (XPS) detections.