煤泥水中微细高岭石颗粒聚团分选机理研究

The presence of large numbers of fine kaolinite particles in coal slurry not only does harm to the sedimentation clarification of coal slurry, but also seriously affects the flotation of slurry. This project, based on the heterogeneity of kaolinite particles and the difference of interfacial properties between kaolinite and other slime particles, firstly, by the analysis of mineral composition, surface structure and potential, chemical elements and groups composition, to get the surface structure property information of kaolinite in the coal slurry and establish the stable molecular structures by molecular dynamic simulation. Secondly, the morphology of absorbed particle, best activity ligands of reagents adsorbs on particle surfaces and the best activity place of particle surfaces will be researched by molecular dynamic simulation and experimental research. Meanwhile, the surface energy and the adsorption energy will be calculated to analyze the adsorption mechanism and difference of commonly used agents on different crystal plane of kaolinite particles and the effects of water quality on the adsorption characteristics of reagents on different particle surfaces to explore the agglomeration and separation mechanism of fine kaolinite particle in coal slurry. Finally, the flocculation settling and flotation tests of fine kaolinite particle in the single mineral system will be conducted, for both simulated coal slurry and real coal slurry. The experimental results are compared and analyzed with the simulation results. The results of this research will provide a theoretical support for the efficient treatment of high muddied coal slurry and resource utilization of the fine kaolinite particles from coal slurry.

煤泥水中大量微细高岭石颗粒的存在对煤泥浮选及煤泥水的沉降澄清处理具有严重的不利影响。项目从高岭石颗粒各晶面异质性及与其他煤泥颗粒界面性质的差异出发，拟通过矿物组成、表面结构和电位、元素和基团组成分析，获取煤泥水中高岭石颗粒表面结构参数信息并进行分子动力学弛豫优化，构建稳定的分子结构模型；采用分子动力学模拟和试验相结合的方法研究药剂在颗粒表面的吸附形貌、最佳配位活性基团及颗粒各晶面最佳配位活性位置，并计算表面能和吸附能，分析水分子、离子、药剂在高岭石颗粒各晶面和其他煤泥颗粒表面的吸附微观机理及彼此间的竞争吸附机制和差异，掌握水质条件对药剂在煤泥颗粒各晶面吸附特性的影响规律，探索煤泥水中微细高岭石颗粒的聚团分选机理；开展单一矿物、人工混合和真实煤泥水中微细高岭石颗粒的聚团沉降和浮选试验研究，并与模拟结果对比分析。研究成果可以为高泥化煤泥水的高效处理和煤泥水中微细高岭石的资源化利用提供理论支持。

煤泥水中大量微细高岭石颗粒的存在对煤泥浮选及煤泥水的沉降澄清处理具有严重的不利影响。本项目用试验和密度泛函理论研究方法模拟研究了Fe、C等杂质元素在煤伴生高岭石颗粒表面的赋存机理及Al/Si的类质同像置换规律，构建了煤伴生高岭石颗粒各面的分子结构模型，从高岭石颗粒各晶面及不同矿物颗粒界面性质出发，研究了煤泥水中聚团药剂在煤伴生高岭石颗粒各晶面的吸附微观机理，掌握煤泥水溶液化学性质对药剂在颗粒各晶面吸附特性的影响规律。研究结果表明：煤的酚羟基（Ph-OH）单元在Fe(Ⅱ)_K、Fe(Ⅲ)_K表面吸附平衡后单元中的苯环近似平行于表面，而碳羟基（C-OH）单元吸附平衡后单元中的碳环近似垂直于表面；C-OH单元更容易在Fe(Ⅱ)_K（001）面发生吸附，而Ph-OH单元更容易在高岭石Fe(Ⅲ)_K（00-1）面发生吸附；水分子主要通过类似于“洞水”分子的A型和类似于“连接水”分子的B型两种形式吸附在高岭石颗粒表面，从而形成一层紧密、稳固的水化膜，其中A型是水分子在颗粒表面的主要吸附形式；十二胺极性头基，其离子形式在高岭石（001）和（00-1）面上的吸附能均比分子形式大得多；对于油酸钠极性头基，分子形式在这些表面上的吸附能比离子形式的更大；十二胺比油酸在高岭石颗粒各晶面的吸附性能更好；Mg2+、Al3+取代的蒙脱石等粘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，十二烷基伯胺阳离子以三个N-H…O氢键，仲胺阳离子以两个N-H…O氢键，叔胺阳离子以一个N-H…O氢键而吸附在蒙脱石颗粒表面，其最佳吸附位置均位于蒙脱石颗粒表面Mg2+→Al3+晶格取代上方的表面氧六元环上，甲基胺类阳离子的吸附能顺序为十二烷基伯胺>十二烷基仲胺>十二烷基叔胺>十二烷基季铵。同时开展了微细高岭石、蒙脱石、石英颗粒单一及混合体系的聚团分选试验研究，对模拟结果进行了初步验证，研究结果对微细高岭石颗粒的聚团分选及创新高泥化煤泥水处理方法和新药剂开发都具有重要的理论和应用价值。