煤泥颗粒表面水化是煤泥脱水困难的重要因素之一，通过弱化煤泥颗粒表面水化膜促进煤泥高效脱水是一种新的技术方法。为掌握基于弱化水化膜促进煤泥脱水机理，采用密度泛函理论方法模拟了不同长链烷基季铵阳离子(表面活性剂)在煤泥水主要矿物颗粒表面的吸附，通过对吸附构型、Mulliken键布局及电荷的分析，研究了水及药剂在高岭石(001)面、α-石英(001)面和蒙脱石(001)面的吸附机理;通过开展煤泥脱水试验和接触角测试，探讨长链烷基季铵盐药剂对煤泥水分和表面润湿性的影响规律。结果表明，水分子在不同种类矿物(001)面的吸附稳定性顺序为石英>高岭石>蒙脱石，石英对煤泥脱水影响大于高岭石和蒙脱石;长链烷基季铵盐药剂在矿物表面的吸附稳定性明显高于水分子，说明药剂与水分子的竞争吸附作用顺序是蒙脱石>石英>高岭石;长链烷基季铵盐与几种矿物(001)表面吸附均是以静电引力为主，弱氢键为辅。随着长链烷基季铵盐药剂用量的增加，煤泥滤饼水分先减少后增加，当药剂用量为500 g/t效果最好，水分降低2.25%以上;随着药剂用量和链长的增加煤泥表面疏水性显著增加。控制药剂用量是实现高效煤泥脱水的技术关键，添加适量的表面活性剂有利于弱化矿物表面的水化膜，过量长链烷基季铵盐阻碍煤泥脱水。

The hydration of coal slime particle surface is an important reason for the difficulty in coal slime dewatering. Promoting the high efficiency dewatering of coal slime by weakening the hydration layer on the coal slime particle sur- face is a new technical method. To understand the mechanism of dewatering based on the weakened hydration layer on the coal slime surface,the density functional theory(DFT) was employed to study the adsorption mechanism of water molecules and surfactants on the kaolinite(001) surface,α-quartz (001) surface and montmorillonite (001) surface.The adsorption configuration,Mulliken bond populations and charge of long-chain alkyl quaternary ammonium salts on the main mineral particle surfaces were simulated and analyzed. Also,the effects of long-chain alkyl quaternary ammo- nium cations on the moisture content and surface wettability of coal slime particles were investigated by means of coal slime dewatering and contact angle tests. The results show that the adsorption stability of water molecule on different mineral surfaces is in the order of α-quartz (001) surface>kaolinite (001) surface>montmorillonite (001) surface, and the effect of quartz on the dewatering of coal slime is greater than that of kaolinite and montmorillonite. The ad- sorption stability of long-chain alkyl quaternary ammonium cations on the mineral surface is significantly higher than that of water molecule,and the order of competitive adsorption between surfactants and water molecules on the mineral surface is montmorillonite>quartz>kaolinite. The different long-chain alkyl quaternary ammonium cations adsorption on the mineral surfaces is via weak hydrogen bond and electrostatic attraction,and the electrostatic attraction is dominant. With the increase of the dosage of long chain alkyl quaternary ammonium salt,the moisture content of filter cake first decreases and then increases. When the dosage is 500 g / t,the dewatering efficiency reaches the optimum,wherein the moisture content decreases by 2. 25% . As the dosage and chain length of alkyl quaternary ammonium salt increase,the hydrophobicity of coal slime surface increases significantly. The key to achieve an efficient dewatering of coal slime is to control the dosage of surfactant. An appropriate dosage of surfactant is conducive to weakening the hydration layer on the mineral surface. Excessive long-chain alkyl quaternary ammonium salt would hinder the dewatering of coal slime. The hydrophobic modification of the coal slime particle surface based on the surfactant provides a theoretical ba- sis for the efficient dewatering of coal slime.