Investigation of micro bubbles enhanced quartz flotation combined with the extended DLVO theory

Micro and nano bubbles assisted mineral particle flotation can effectively improve the surface hydrophobicity of mineral particles, increase the probability of collision and adhesion between particles and air bubbles. Meanwhile, selecting suitable flotation combination collectors can also enhance the selectivity of mineral particles for further improving the flotation recovery of minerals. In this study, under the presence of micro bubbles, a high quartz flotation recovery of 98.3 % was obtained by a combination collector of DTAC/SDS with the molar ratio of 1: 1 and the dosage of 700 mg/L at pH 9. According to the extended DVLO theory, the relationship between Van der Waals interaction energy ( E v ), hydrophobic interaction energy ( E h ), electric double-layer interaction energy ( E e ) and flotation factors such as the type and concentration of flotation reagents, pH of solution and micro bubble treatment was the deeply investigated. The mechanism of micro bubbles enhancing quartz flotation behavior is regarded as the generated strong capillary bridge attraction between the air bubbles on the surfaces of two hydrophobic particles, which promotes large amounts of fine particles aggregating and forming larger hydrophobic particles. Thereby, the probability of collision and adhesion between bubbles and particles significantly increases and flotation efficiency improves. The experimental results are also evidenced by the calculation of total interaction energy ( E t ) and energy barrier.