Application of novel ionic liquids in flotation separation of quartz and magnesite and its mechanism

Application of a novel ionic liquid as flotation reagent in the flotation separation of quartz and magnesite has been investigated. The flotation behavior and surface properties of quartz and magnesite flotation with dodecyl trimethyl ammonium-diethylphosphonic acid (N12111-DEPA) as flotation reagent were studied by microbubble flotation experiments, contact angle, fourier transforming infrared spectra (FT-IR), and X ray photoelectron spectroscopy (XPS) spectrometer analysis. The micro-flotation of single mineral results demonstrated that N12111-DEPA exhibited a good collection selectivity for quartz. Under the optimum flotation conditions of pulp pH 7.0 and 15 mg/L N12111-DEPA, the grade and recovery of MgO in concentrate were 41.21 % and 97.45 %, respectively. The analysis of contact angle shown that N12111-DEPA increased the surface hydrophobicity of quartz and decreases the surface hydrophobicity of magnesite, thus increasing the difference of floatability between the two minerals. The analysis of FT-IR and XPS confirmed that the cations of N12111-DEPA are mainly adsorbed on quartz surface through electrostatic affinity, while the anions of N12111-DEPA are mainly adsorbed on magnesite surface through chelation with exposed magnesium sites on mineral surface. This demonstrated that N12111-DEPA had a good application potential in reverse flotation separation of magnesite and quartz.