Thermodynamic behavior and flotation kinetics of an ionic liquid microemulsion collector for coal flotation

Abstract

To develop a new type of coal slime collector, an ionic liquid microemulsion was prepared using 1-alkyl-3-methylimidazolium chloride ([Cnmim]Cl, where n = 12, 14, or 16) as a surfactant, n-alcohol (n-butanol, n-pentanol or n-hexanol) as a cosurfactant, and n-dodecane as the oil phase, and the interfacial composition and thermodynamic changes of these systems were investigated using Schulman’s titration. Therefore, the [C16mimCl]/n-dodecane/n-pentanol/water microemulsion system was chosen as the microemulsion collector. Moreover, the droplet size and polydispersity index (PDI) of the microemulsion collector were determined, and the average droplet radius of the microemulsion was about 32 nm and the PDI was less than 0.06. The average droplet radius was found to range from 30 to 50 nm by transmission electron microscopy analysis. Furthermore, the coal slime flotation experiments and flotation kinetics analysis showed that the microemulsion collector applied for coal slime flotation yielded the same behavior as that of n-dodecane, but the collector dose can be reduced by about 43% and the cost is only 71% without the need for a frother. And, of the four kinetic models tested, the flotation process using the microemulsion collector was consistent with the first-order matrix distribution model.