Calcite Flotation in Potassium Oleate/Potassium Dihydrogen Phosphate System

Calcite flotation in acidic media is a difficult task due to the solubility of calcite and consequently the release of calcium ions in the flotation pulp. In addition, the interaction of calcium ions with the flotation reagents requires the correct selection of these reagents. In this study, potassium oleate and potassium dihydrogen phosphate (KH₂PO₄) were used as collector and depressant, respectively. Micro‐flotation experiments were conducted to probe the effect of these chemical reagents as well as their interaction on calcite flotation using H₂SO₄ as a pH regulator. In addition, to elucidate the depressing action of KH₂PO₄ on calcite, electrokinetic properties of calcite have been measured in relation to pH and in the absence and presence of KH₂PO₄. Moreover, thermodynamic calculations were used to rationalize the reasons for calcite depression as well as the adsorption mechanism of KH₂PO₄ onto the calcite surface.