煤泥水中微细颗粒界面间微观作用机理研究

Fine particles in coal slurry water have characteristics of extraordinary fine granularity, high clay mineral content, and strong electronegativity of particle surface, which bring great difficulties to the aggregation settlement, selective separation and dewatering of coal slurry. The basic theory of solving this problem is selective inhibition or enhancement the interactions between multi-component fine particles in coal slurry by interface control. This project took the main fine particles coal and clay minerals in coal slurry water as the research objects, to explore the interface structure properties by analysis of modern advanced technology based on solid/liquid interfacial physicochemical interaction theory, and the surface structure units and interface stability configurations of fine slurry particles were built with the help of quantum chemical/molecular dynamics simulation software. The competitive adsorption mechanism of different surface structure units and the water molecules on different surfaces of minerals were studied using density functional theory, to master the influence of the chemical properties of solution on the interactions between fine particles in coal slurry water. The statistical properties on the interfaces of mineral-water and mineral-mineral were studied by molecular dynamics simulation. The interaction forces between particles were measured directly by AFM, and the feasibility for the selective control of the interactions between fine particles were verified by the experiments of aggregation settlement and selective separation, which can verify the molecular simulation results. The research results will offer the theory proof for aggregation settlement, selective separation and dewatering of coal slurry water.

煤泥水中微细颗粒因粒度细、黏土矿物含量高、颗粒表面电负性强等特点，给煤泥的聚团沉降、选择性分选及脱水等带来极大困难，通过界面调控选择性抑制或强化煤泥水中多组分微细颗粒间相互作用是解决这一问题的基础理论。课题以煤泥水中主要微细颗粒煤和黏土矿物为研究对象，以固液界面物理化学作用理论为基础，通过现代先进分析技术探索煤泥颗粒界面结构性质，借助量子化学/分子动力学模拟软件构建煤泥水微细颗粒表面结构单元及界面稳定构型；采用密度泛函理论研究不同表面结构单元和水分子在矿物颗粒不同晶面的竞争吸附机制，掌握溶液化学性质对煤泥水微细颗粒间相互作用的影响规律；采用分子动力学模拟研究矿物-水及矿物-矿物界面的统计学性质。采用AFM直接测试颗粒间作用力，并通过聚团沉降和选择性分选试验验证煤泥水中微细颗粒界面间微观作用选择性调控的可行性，验证分子模拟结果。研究可以为煤泥水聚团沉降、选择性分选及脱水提供理论支持。

煤泥水中微细颗粒因粒度细、黏土矿物含量高、颗粒表面电负性强等特点，给煤泥的聚团沉降、选择性分选及脱水等带来极大困难。通过界面调控选择性抑制或强化煤泥水中多组分微细颗粒间相互作用是解决这一问题的基础理论。课题以煤泥水中主要微细颗粒煤和黏土矿物为研究对象，通过现代先进分析技术分析探索了煤泥颗粒界面结构性质，借助量子化学/分子动力学模拟软件构建了煤泥水微细颗粒表面结构单元及界面稳定构型；采用密度泛函理论揭示了不同表面结构单元和水分子在矿物颗粒不同晶面的竞争吸附机制；采用分子动力学模拟分析了矿物-水及矿物-矿物界面的统计学性质，明晰了煤泥水中多组分微细颗粒界面间微观作用机理；采用AFM测定了煤泥水中同类颗粒间的作用力，并进行了煤泥水中微细颗粒界面间微观作用选择性调控试验验证。研究表明，水分子主要通过氢键作用吸附在高岭石及氧化煤表面，随着水分子数的增加，水分子间排列的有序度不断减小，且水分子在颗粒表面逐渐形成多个水分子层；煤泥水中微细氧化煤与煤系高岭石颗粒间的微观作用主要是氧化煤表面含氧官能团与高岭石表面形成的氢键作用和氧化煤中苯环与高岭石表面间的静电引力作用，其中以静电引力作用为主导，高岭石中Fe杂质的存在显著增强了高岭石与氧化煤颗粒间的相互作用；胺/铵盐类药剂能够通过氢键和静电引力作用稳定吸附在煤系高岭石表面，通过氢键作用及分子间作用力与氧化煤颗粒发生吸附，但吸附不稳定；铵盐类药剂能够通过对颗粒表面疏水改性强化颗粒间相互作用促进煤泥颗粒形成疏水聚团，但其对氧化煤的聚团效果远小于对煤系高岭石颗粒的聚团效果；微细粒煤系高岭石能够在煤颗粒表面发生罩盖，显著影响煤泥浮选效率，通过药剂抑制浮选过程煤与高岭石颗粒间相互作用是解决这一问题的关键。