Flotation behavior and separation mechanism of quartz and iron minerals in α-bromolauric acid reverse flotation system

A new type collector alpha-Bromolauric acid (alpha-BLA) had been proved to be an efficient collector for quartz flotation. However, the effects of alpha-BLA on the flotation behavior of iron minerals and quartz-iron separation had not been investigated. In this study, collector alpha-BLA was synthesized in the laboratory. The flotation behavior of quartz, hematite and magnetite under alpha-BLA reverse flotation system were investigated and the separation mechanism of quartz-irons was studied by contact angle, zeta-potential and infrared spectroscopy. The results showed that the optimum flotation pH was 11.5 for quartz, 6.45 for hematite and 6.97 for magnetite. The best alpha-BLA concentrations was 75 mg/ dm(3) for quartz flotation, 125 mg/ dm(3) for hematite and magnetite flotation. The activator CaCl2 had little effect on the flotation of hematite and magnetite, but the minimum dosage 50 mg/ dm(3) of activator CaCl2 was necessary for quartz flotation. On the contrary, starch had no effect on the flotation of quartz, while the recoveries of magnetite and hematite tended to be 0% as starch concentration more than 80 mg/ dm(3). The separation mechanism of quartz from iron minerals under alpha-BLA reverse flotation system was that the starch could be selectively adsorbed on the surface of hematite and magnetite in the form of strong hydrogen bond adsorption. However, the same adsorption of starch did not occur on the surface of quartz, so the alpha-BLA can be successfully adsorbed on the surface of activated quartz to make the quartz strongly hydrophobic, and then to be floated out.