Abstract: In order to investigate the effect of the molecular structure of dodecyl phosphate on the flotation performance of apatite，the molecular structure characteristics of dodecyl phosphate and its mechanism on the surface of apatite crystal were studied by means of quantum chemical simulation. Using CASTEP module of MS software，this paper firstly optimized the molecular structure of dodecyl phosphate in molecular state and ionic state，and obtained the net charge，Mulliken charge distribution，dipole moment and the composition and energy of HOMO of dodecyl phosphate molecule and its anion. Then，the interaction model of dodecyl phosphate anion on the surface of fluorapatite was simulated to obtain the interaction distance and adsorption energy between dodecyl phosphate anion and fluorapatite. The results show that compared with the dodecyl phosphate molecule，the dodecyl phosphate anion has stronger electron supply ability，van der Waals action ability and reaction activity. The results also indicate the adsorption energy between the dodecyl phosphate anion and the fluorapatite surface is negative，and the adsorption between the two can occur spontaneously and form chemical bonds，therefore， the dodecyl phosphate anion has the potential as a collector of fluorapatite. Finally，the simulation results are verified by single mineral flotation test: dodecyl phosphate can be used as flotation collector of fluorapatite.

Key words: Fluorapatite, Dodecyl phosphate, CASTEP module, Dipole moment, Collector, Flotation