Effect of Acidified Water Glass on Flotation Separation of Fluorite and Calcite

Flotation separation of fluorite and calcite, by adding AWG (acidified water glass) as inhibitor and NaOL (sodium oleate) as collector, has been investigated by means of micro-flotation tests, flotation solution chemistry, zeta potential measurements, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) in this study. The micro-flotation results demonstrate that NaOL exhibits strong collecting power toward both fluorite and calcite, making effective separation of the two minerals unachievable in the absence of depressants. When AWG is applied as a depressant, it shows selective depression toward calcite, while exhibiting little effect on fluorite. Solution chemistry analysis, contact angle measurements, zeta potential measurements, FTIR, and XPS analyses collectively confirm that AWG can adsorb onto the calcite surface, but not onto fluorite. This adsorption prevents NaOL from interacting with the calcite surface. In contrast, the absence of AWG adsorption on fluorite allows NaOL to freely adsorb and thereby collect fluorite particles.