Flotation separation of smithsonite and calcite in sodium oleate system using soluble starch as depressant

Owing to the similar surface properties of smithsonite and calcite, effective flotation separation of these two minerals is difficult in the mineral processing industry. In this study, we investigated the effect of soluble starch (SS) as a depressant on the flotation separation of smithsonite and calcite. Microflotation test, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculation were used to further explore the flotation mechanism. The results showed that soluble starch can effectively reduce the floatability of calcite. Different chemical bonds were formed during the interaction between soluble starch and mineral surfaces, resulting in different adsorption energies and leads to differences in flotation recovery rates.