煤泥水中微细高岭石/蒙脱石颗粒表面水化分子动力学模拟研究

摘要

煤泥颗粒界面水化是煤泥水难以沉降脱水的主要原因,采用分子动力学模拟研究了煤泥水中主要微细黏土矿物颗粒高岭石及蒙脱石颗粒界面水化分子动力学特性,模拟计算了矿物颗粒界面水平衡构型、界面原子浓度、水分子扩散系数及金属离子的影响.研究结果表明:水分子能够通过氢键在高岭石及蒙脱石颗粒表面发生水化作用;随水覆盖率(或水分子数)的不断增加,矿物颗粒表面对水分子的束缚力逐渐减小,界面处的氢键作用逐渐减弱,其中水分子在亲水性的高岭石和蒙脱石界面能逐渐形成3个水分子层,总厚度为(8 ～ 10)×10-10 m;高岭石(001)面水化程度大于蒙脱石(001)面;二价金属离子对蒙脱石水化的促进作用强于一价金属离子.%The surface hydration is one of the main reasons for the difficulty of coal slurry water sedimentation and dewatering,the molecular dynamics simulation on the surface hydration of fine slurry particles was investigated in this study using the main fine clay mineral particles (kaolinite and montmorillonite) in coal slurry water as research objects.The results indicate that water molecules can hydrate on the surface of kaolinite and montmorillonite by hydrogen bonding.The binding force between mineral surfaces and water molecules decreased with the increase of water coverage (or the number of water molecules),the hydrogen bond at the interface gradually weakened,and the water molecules on hydrophilic kaolinite and montmorillonite surface can be gradually formed three water molecules shells,the total thickness is (8-10)× 10-10 m,and the degree of hydration on different particle surfaces is in order of:kaolinite (001) surface＞montmorillonite (001) surface.The effect of divalent metal ions on montmorillonite is stronger than that of monovalent metal ions.