Alkanes-esters mixed collector enhanced low rank coal flotation: Interfacial interaction between oil drop and coal particle

The interaction between oil collector drop and coal particle is important for low-rank coal (LRC) flotation. This paper investigated such interactions using dodecane (D), ethyl esters (E) and dodecane-esters mixed collector (MC). Measurements of oil drop-coal induction time and detachment force were conducted at a mesoscopic scale. The micro adsorption mechanism of oil collectors was revealed by wetting heats and FTIR measurements. Flotation results showed MC, especially dodecane-ethyl laurate, obtained high yield and low ash clean coal. There was a shorter induction time and higher adhesion strength between LRC particle and MC drop. The wetting heat of MC was greater than the sum of wetting heat of the two single collectors. FTIR analysis indicated that D validly adsorbed to the methyl or aromatic groups, and E bonded with the oxygen-containing groups. The macro flotation results was well interpreted by the interfacial interaction of collector-coal at the mesoscopic and micro scales.