磁性膨润土絮凝剂沉降煤泥水的机理分析

摘要

针对高灰高硫原煤洗选所产生的含有较多微细颗粒、呈酸性的煤泥水难沉降的缺陷,采用溶剂热法研制出新型的Fe3O4-壳聚糖/膨润土复合絮凝剂.通过着重分析煤泥水pH值对沉降过程的影响,并结合该絮凝剂的结构及理化性能,从扩展DLVO理论的角度上出发,系统地研究磁性膨润土复合絮凝剂与煤泥水微观作用机制,揭示二者之间的絮凝沉降机理.结果表明:交联剂与壳聚糖的加入成功制备了稳定结构的磁性膨润土复合絮凝剂;在煤泥水pH=5时,含有大量的—NH3+正电性基团的絮凝剂通过静电中和以及氢键缔合作用可明显降低煤泥表面的电负性,显著减小煤粒间的静电作用能,降低范德华作用排斥势能,增强煤粒间的凝聚能力,加速沉降.%Aiming at the settlement problem of coal silme water derived from the washing of high ash and sulfur coal,a new type of Fe3 O4-chitosan/bentonite composite flocculant was synthesized by solvothermal method.Through focusing on the effect of the pH value of coal slurry water on the settlement process,combining with the physical and chemical properties of the flocculant,the flocculation precipitation mechanisms between slime water properties and flocculation were investigated.The results indicate that the flocculant containing —NH3+electropositive groups can effectively reduce the electronegativity of the slurry surface,the electrostatic effect between coal particles and the Van der Waals repulsive potential energy and significantly improve the effect of slurry particle hydrophobic aggregation at pH=5.The flocculant possesses certain reusability with the help of additional magnetic field.