Activation mechanisms of quartz flotation with calcium ions and cationic/anionic mixed collectors under alkalescent conditions

Abstract

High-efficiency flotation of quartz under alkalescent conditions remains challenging owing to the leak of an effective activator. In this research, high quartz flotation recovery was achieved with Ca2+ and cationic/anionic mixed collectors under alkalescency, while activation mechanisms were systematically investigated. Micro-flotation results indicated that 81.60% quartz were floated with 5 × 10−4 mol/L of CaCl2, 2.5 × 10−4 mol/L of sodium oleate (NaOL) and 3.0 × 10−5 mol/L of Dodecylamine (DDA) at pH 9.0. However, under 10% of quartz were recovered without adding CaCl2 or only using CaCl2 and NaOL. Zeta potential, infrared spectroscopy and X-ray photoelectron spectroscopy results confirmed that NaOL adsorbed on calcium-activated quartz surface via chemisorption and DDA could enhance the hydrophobicity of quartz via charge neutralization. Atomic Force Microscope imaging and revealed that Ca2+ could adsorb on quartz in patches, which was subsequently adsorbed with mixed NaOL/DDA. This outcome demonstrated that CaCl2 could promote co-adsorption of cationic/anionic mixed collectors on quartz at mildly basic pH.