Molecular Dynamics Simulation Of Adsorption Of Combined Collectors Of Dodecylamine And Oleic Acid On Surface Of Lepidolite Surface

With the development of flotation theory,research of flotation system not only concentrated on flotation responses,the researchers through the emerging research methods-molecular simulation method,building the flotation system model,from the microscopic field more intuitive observation of the flotation reaction about collectors or water adsorbing on the mineral surface,deepened the understanding of the mechanism of flotation.In this paper,the band structure and density of states were studied by using quantum chemistry theory,and the relationship between the lepidolite crystal structure and its floatability was discussed.In addition,the dissociation surface(001)of lepidolite was analyzed in band structure and density of states.At the same time,the interaction energy of collector on the surface of lepidolite was calculated using the molecular dynamics software and was verified with the aid of pure lepidolite flotation results.The study of the electronic structure shows that density of states near Fermi level in the lepidolite crystal structure is mainly contributed by the 2p orbital of O atom and the 3p orbital of Si atom.Therefore,the O atom and the Si atom are the active sites on the surface of the lepidolite.During lepidolite flotation test,its surface dissociated and exposed a large number of K + and [SiO4]-,K + in aqueous solution easily soluble and it can be combined with a large number of hydroxyl,making lepidolite carry negative electricity within a large pH range and a low PZC,resulting in lepidolite has a good flotability with cationic collector lauryl amine,while has a poor flotability with anionic collector sodium oleate.Molecular dynamics simulations of collectors adsorbed on the lepidolite(001)surface indicates that the hydration of water molecules is not dominant in the interaction between K + and the lepidolite surface,and K + are still adsorbed on the lepidolite surface.The lepidolite(001)surface formed a water layer with adsorption energy of-11.35 kcal/mol,which less than the interaction energy of the collector adsorbed on the lepidolite surface,and thus the interaction configuration of the collector with the lepidolite(001)surface,which two layers was separated by water layer.The collecting ability of three reagents adsorbed on the the lepidolite(001)surface as combined collectors(dodecylamine and oleic acid)> dodecylamine> oleic acid,consistent with the vacuum environment.The interaction between the amine group and the lepidolite(001)surface is greater than that the hydroxyl group adsorbed on the lepidolite(001)surface.In flotation,the agent molecules through the carboxyl or amino militate with the spodumene layer(001)surface water molecules,through the role of the hydrophobic hydrocarbon chain pull lepidolite up.In lepidolite flotation,the flotation indexes of the oleic acid and dodecylamine combined in one to one was best,and its optimum flotation environment was in the neutral and alkali environment.Pure mineral flotation test was carried out to verify that the composite agent was greater than that of single collector under neutral conditions for collecting lepidolite,when the oleic acid and dodecylamine was combined in one to one.