1. School of Chemical and Environmental Engineering,China University of Mining and Technology(Beijing),Beijing　 100083,China; 2. School of Materials Science and Engineering,Anhui University of Science and Technology,Huainan　 232001,China

与黄铁矿硫共生的碳质提高了煤系黄铁矿在煤泥浮选过程中的可浮性,为了降低煤系黄铁矿的可浮性及脱除精煤中的黄铁矿,分析煤系黄铁矿碳质中碳元素的存在形式及其与疏水性关系的机理具有重要的意义。采用微量热仪和扫描电子显微镜比较了中国典型矿区的矿系黄铁矿和煤系黄铁矿的润湿热及表面碳质中碳元素含量差异,试验结果表明:与矿系黄铁矿相比,各煤系黄铁矿的润湿热绝对值均较小,碳质中碳元素含量较高,导致疏水性可能因表面吸附碳原子而较强。采用基于密度泛函理论(DFT)和平面波赝势的方法模拟了水分子在理想黄铁矿表面及含碳原子吸附的黄铁矿表面的吸附过程并计算了水分子的吸附能、键Mulliken布居及键长、电荷密度及电子态密度。计算结果表明:与理想黄铁矿表面相比,水分子在含碳原子吸附的煤系黄铁矿表面的吸附能由负值变为正值,吸附碳原子处的黄铁矿表面变成疏水性,黄铁矿表面铁原子的3d轨道先与碳原子的2p轨道形成强烈的Fe—C键,碳原子的2p轨道再与水分子中氧原子的2p轨道形成微弱C—O键,因C—O键作用微弱导致碳原子的吸附不利于水分子在黄铁矿表面的吸附,从量子化学的角度揭示了煤系黄铁矿表面吸附碳原子后对其疏水性影响的机理。

The carbonaceous substance physically accreted with pyrite improves the floatability of coal-pyrite. In order to reduce the floatability of coal-pyrite selectively and remove the pyrite in coal,it is very important to study the exist- ing style of carbon atom on the coal-pyrite surface and the mechanism between carbon atom and hydrophobicity. The wetting heat and carbon element content of mineral-pyrite and coal-pyrite were compared by the microcalorimeter and Scanning Electron Microscope. The experiment results showed that the wetting heat of coal-pyrite was bigger and the carbon element content of carbonaceous substance were higher than the mineral-pyrite generally. With the first-princi- ple method of density functional theory ( DFT) and the plane-wave ultrasoft pseudopotential method,the adsorption process of water on the perfect pyrite surface and surface adsorbed by carbon atom was simulated. And the adsorption energy,bond Mulliken population,electron density and density of states were calculated and discussed. The simulation results showed that compared with the perfect pyrite surface,the adsorption energy on the surface adsorbed by carbon atom was positive. The surface adsorbed by carbon atom became hydrophilic. The simulation results were consistent with the results of wetting heat. The mechanism of the influence of carbon atom’s adsorption on coal-pyrite hydropho- bicity was revealed from the view of quantum chemistry.

中央高校基本科研业务费资助项目(2010YH11)；

Xi Peng,Liu Wenli,Yang Zongyi,et al. Influence of carbon atom adsorption on coal pyrite hydrophobicity based on quantum chemistry [J]. Journal of China Coal Society,2017,42(5):1290-1296.