Density functional theory study on natural hydrophobicity of sulfide surfaces
(1. School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China;
2. Guangxi China Tin Group Co., Ltd, Liuzhou 545006, China;
3. College of Materials Science and Engineering, Guangxi University, Nanning 530004, China;
4. College of Resources and Metallurgy, Guangxi University, Nanning 530004, China)
2. Guangxi China Tin Group Co., Ltd, Liuzhou 545006, China;
3. College of Materials Science and Engineering, Guangxi University, Nanning 530004, China;
4. College of Resources and Metallurgy, Guangxi University, Nanning 530004, China)
Abstract: Adsorption of water on sulfide surfaces and natural floatability of sulfide minerals were studied using density functional theory (DFT) method. All computational models were built in a vacuum environment to eliminate the effects of oxygen and other factors. H2O molecule prefers to stay with pyrite and sphalerite surfaces rather than water, whereas for galena, chalcocite, stibnite, and molybdenite, H2O molecule prefers to stay with water rather than the mineral surfaces. On the other hand, pyrite surface favors N2 more than water, while sphalerite surface cannot adsorb N2. These results show that galena, stibnite, chalcocite, and molybdenite are hydrophobic, while sphalerite is hydrophilic. Although pyrite has certain hydrophilicity, it tends to be aerophilic because the reaction of pyrite with H2O is weaker than pyrite with N2. Thus, pyrite, galena, chalcocite, stibnite and molybdenite all have natural floatability.
Key words: sulfide minerals; water adsorption; natural floatability; density functional theory