Effects of calcium ions on malachite flotation with octyl hydroxamate

Abstract

In this study, the effects of calcium ions on the flotation of malachite with octyl hydroxamate collector has been investigated using micro-flotation, zeta potential, contact angle, adsorption, and particle size measurements. Although the adsorption amount of collector and the hydrophobicity of malachite surface were not influenced by the addition of 1 × 10−2 mol/L CaCl2 at the optimized flotation pH 9, it was found that the malachite flotation recovery was enhanced by the addition of CaCl2 in the pH range of 6–11. In the presence of CaCl2, energy barrier between the malachite particles and the bubbles were lower, leading to the aggregation of malachite particles, and the enhanced malachite recovery. However, at pH > 11, the formation of Ca(OH)+ and Ca(OH)2 species on malachite surface inhibited its flotation.