Cooperative effect of electrolyte and oscillatory air supply on recovering graphite in column flotation

Abstract

Column flotation tests of natural graphite were carried out in electrolyte solutions free of any organic chemicals using an oscillatory air supply (at a switching frequency of 25 Hz with an on/off time ratio of 0.1). The results were compared with those obtained using conventional steady air supply. The electrolyte solutions were prepared at different ionic strengths (0.3–6 M) from single (NaCl or AlCl3) or mixed inorganic electrolytes (NaCl-CaCl2, NaCl-CaCl2-MgCl2-AlCl3). The present work identified a cooperative effect of electrolyte addition and use of oscillatory air supply on improving graphite flotation kinetics. It demonstrates a potential for making graphite flotation 80% faster without relying on commonly used freshwater or organic reagents in flotation.