Mechanism of manganese ion interaction with the surface of scheelite and calcite and its effect on flotation separation

Abstract

Scheelite and calcite have similar surface physicochemical qualities and share the same calcium ion active sites in the mineral surface, making their separation more challenging. In this work, the effect of manganese chloride on the flotation separation of scheelite and calcite was explored utilizing flotation tests, Zeta potential tests, Fourier-transform infrared spectroscopy (FTIR), adsorption amount estimation, and X-ray Photoelectron Spectroscopy (XPS). The flotation test revealed that scheelite recovery increases gradually with increasing manganese chloride following manganese chloride addition, while the recovery of calcite gradually decreases. The recovery difference between the two minerals reached 82.84% points, achieving a better separation of scheelite and calcite. Manganese chloride produced manganese ions on the surface of scheelite, as confirmed by infrared spectroscopy, adsorption measurements, and X-ray Photoelectron Spectroscopy (XPS). Manganese ions were adsorbed on the surface of scheelite when manganese dichloride was added, increasing the number of cations on the surface and improving scheelite sodium oleate (NaOL) interaction. Furthermore, the addition of manganese ions increased the selectivity of sodium silicate, which increased its inhibition on the calcite surface, reducing sodium oleate adsorption on the calcite surface and thus reducing flotation recovery, achieving the goal of separating the two minerals.