Attachment characteristics between oily bubbles and low rank coal particles

Bubble-mineral particles attachment and mineralization process are critical to flotation technology which can realize the effective separation of coal and gangue. It is indispensable for understanding the mechanism of mineraliza- tion process in flotation to investigate the interaction between low rank coal particles and reactive oily bubbles by elec- trochemistry studies and induction time measurements. In this paper,the influence of pH of solution and surfactants on the interaction between low rank coal particles and reactive oily bubbles which can be estimated by the DLVO theory was investigated. And the attachment efficiency was evaluated by the induction time measurements. The results showed that the isoelectric point(IEP) of coal particles and diesel oily bubbles was observed over the range of pH 2 -3 and pH 3-5,respectively. No interaction energy barrier between coal particles and diesel oily bubbles was observed in the tested solution of pH 3,while the interaction energy barrier appeared and gradually increased with the increase of pH value when it exceeded 3. It indicated that the interaction energy barrier and induction time between coal particles and diesel oily bubbles modified by surfactants 2-ethylhexanol and didodecyldimethylammonium bromide were lower than diesel oily bubbles,with the maximum decrease of 74. 35% and 86. 45% respectively.