基于量子化学/分子动力学的煤泥水微细黏土颗粒界面调控机理研究

The separation, settlement and dewatering of coal slurry containing a considerable amount of clay minerals fine particles charged negative and hydrated are very difficult.The key scientific issue is the interfacial characteristics and its control of fine clay minerals particles. This project aims at interfacial characteristics and its control of fine clay minerals particles in coal slurry. The project bases itself on solid/liquid interfacial physicochemical interaction theory, with the help of quantum chemistry and molecular dynamics simulation, through the theory analysis and the modern instrument measurement, explores the physicochemical interaction mechanisms of fine clay minerals particles and coal slurry solution chemistry environment, and constructs rotation solid interface model. The effects of different groups and structure reagent, water molecular and cations on clay minerals particles frontier orbitals energy, atomic coefficient and reaction activation are investigated by density functional theory method. The adsorption mechanism of fine clay minerals particles surface with reagent molecular and et al. is explored by using electronic structure, Mulliken population, adsorption configuration and so on. The law of fine clay minerals particles interface control would be grasped. Microcalorimetry is applied to study the adsorption thermodynamics and dynamics model of regent on fine clay minerals particles surface. Hydrophobic coagulation experiments of slurry are carried out based on the study of interface control and hydrophobic coagulation technique of coal slurry is investigated. The research results will offer the theory proof for regent optimizing selection and developing of coal slurry particles interfacial control.

煤泥水中微细黏土矿物颗粒因其粒度细、表面荷电及水化等给煤泥分选、沉降及脱水等带来很大困难，而颗粒界面性质及调控是核心问题。课题以煤泥水中微细黏土矿物颗粒界面性质及调控为研究对象，以固液界面物理化学作用理论为基础，借助量子化学/分子动力学模拟，通过理论及现代仪器分析探索煤泥水溶液化学环境与微细矿物颗粒界面物理化学作用机制，构建界面稳定构型；采用密度泛函理论研究不同官能团和结构药剂分子、水分子及离子对微细矿物颗粒表面前线轨道能量、原子系数组成及表面反应活性的影响，通过分析电子结构、Mulliken布居、吸附构型等揭示药剂等分子在微细矿物颗粒界面的吸附机理，掌握微细矿物颗粒界面调控理论规律；利用微量热方法探索药剂在矿物颗粒界面吸附热力学过程，建立吸附动力学模型；进行煤泥颗粒界面疏水调控试验验证，提出微细煤泥颗粒疏水聚团技术原型。研究可以为微细煤泥颗粒界面调控药剂优化选择及药剂设计提供理论支持。

煤泥水中微细黏土矿物颗粒因其粒度细、表面荷电及水化等原因给煤泥分选、沉降及脱水等带来很大困难，而颗粒界面性质及调控是核心问题。课题以煤泥水中微细黏土矿物颗粒界面性质及调控为研究对象，借助量子化学/分子动力学模拟，通过理论及现代仪器分析探索煤泥水溶液化学环境与微细矿物颗粒界面物理化学作用机制，构建了界面稳定构型；通过分析电子结构、Mulliken布居、前线轨道、吸附构型等揭示了不同官能团和结构药剂分子、水分子及离子在微细矿物颗粒表面吸附机理，掌握了微细矿物颗粒界面调控理论规律；利用微量热方法探索药剂在矿物颗粒界面吸附热力学过程，并进行了煤泥颗粒界面疏水调控试验验证。研究表明，Mg2+、Al3+取代的蒙脱石等黏土矿物表面点位以及Na+等平衡离子及其周围O原子是反应活性点位；黏土矿物颗粒端面上-SiOH和-AlOH2、-AlOH等基团最容易发生质子化和去质子化反应；水分子主要通过静电和氢键作用吸附于黏土类矿物颗粒的表面，（010）端面对水分子具有更强的吸附作用，吸附能为-82.97~-62.71kJ/mol高于（001）等平面的吸附能（-72.12~-5.77 kJ/moL）；Mg2+、Ca2+、Na + 、K +对蒙脱石界面水化作用能力依次减弱；煤表面含氧官能团吸附水分子的稳定性大小为-COOH> -C=O>Ph-OH> -O-；水分子在黏土矿物颗粒表面形成3个水分子层，总厚度为(8 ~10)×10 -10 m)；阳离子胺/铵盐类疏水改性剂主要通过静电作用和N-H…O氢键作用吸附到蒙脱石等黏土矿物颗粒表面活性点位，并有效改善颗粒表面疏水性，降低颗粒表面电负性，促进颗粒聚团；阳离子胺/铵盐类疏水改性剂在黏土矿物颗粒表面的吸附能（-109.71~-140.96kJ/mol）大于水分子在其表面的吸附能；季铵盐在高岭石颗粒表面的吸附作用是放热反应，属于自发的过程；微细煤与高岭石间的相互作用机制主要是氢键作用和煤结构中苯环与高岭石表面间作用的综合作用；课题提出的煤泥水疏水聚团沉降技术原型可以为煤泥水沉降脱水新技术开发提供依据，黏土颗粒界面吸附活性点位、水分子、离子及不同药剂吸附研究成果可以为微细煤泥颗粒界面调控药剂优化选择及药剂设计提供理论支持。