Mechanism of interaction between mixed collectors and low-rank coal: An experimental and simulation study

In this paper, Ordos low-rank coal was taken as the research object, methyl oleate and diethyl phthalate were used as test reagents, and the differences of coal slime flotation indexes under single collector and mixed collector conditions were compared and analyzed by the batch flotation testing of fine coal. Through DFT calculation, molecular dynamics simulation and Fourier transform infrared spectroscopy (FTIR) test, the mechanism of mixed collector improving the flotation index of low-rank coal was investigated. The results show that the flotation ability of single ester collector for low-rank coal is better than that of traditional oil collector, and the collector can further improve the flotation index of coal slime after mixing. There is a certain internal relationship between the frontier orbital energy and adsorption energy of collector molecules and their harvesting performance. When the single collector reaches adsorption equilibrium on the coal surface, the spatial orientation of the collector molecule is 'horizontal' on the coal surface, and the mixed collector is 'vertical' on the coal surface.