金属离子对蒙脱石颗粒水化作用影响及机理

Effect of Metal Cations on Hydration of Montmorilloniteand its Mechanism

这是一篇矿业工程领域的论文。蒙脱石是对煤泥水沉降影响显著的黏土矿物,其表面带电和易发生水化作用等特性阻碍颗粒间的聚团,使悬浮液保持分散性,恶化煤泥水沉降。基于沉降实验,考查了煤泥水中常见金属离子Na^(+)、K^(+)、Mg^(2+)、Ca^(2+)及Al^(3+)对蒙脱石沉降特性的影响,并采用微量热仪、Zeta电位分析仪及红外光谱仪等表征手段揭示金属离子对蒙脱石水化作用及沉降行为的影响机理。结果表明,与Na^(+)、K^(+)、Mg^(2+)相比,蒙脱石悬浮液或含蒙脱石煤泥水在加入Al^(3+)、Ca^(2+)后,可获得较小的沉降压缩层体积和上清液浊度,沉降效果较好。机理分析表明,加入金属离子可压缩蒙脱石表面双电层厚度,抑制蒙脱石水化作用,有利于蒙脱石聚团沉降。研究结果对处理含蒙脱石煤泥水具有一定指导意义。

This is an article in the field of mining engineering.Montmorillonite is a kind of clay mineral which has significant impact on the sedimentation of coal slime water.Its charged surface and easy hydration hinder the mutual contact between particles,keeping the suspension stable dispersion and worsen the sedimentation of slime water.Based on sedimentationexperiments,we studied the effects of common metal cations Na^(+),K^(+),Mg^(2+),Ca^(2+)and Al^(3+)on the sedimental characteristics of montmorillonite.Meanwhile,the mechanism of various metal cations in the hydration and sedimentation behavior of montmorillonite was investigated by using microcalorimeter,Zeta potential analyzer and infrared spectrometer.The experiment results show that,adding Al^(3+)and Ca^(2+)to montmorillonite suspension or montmorillonite-containing slime water can result into smaller sedimentation compressed layer and lower turbidity of the supernatant.So,Al^(3+)and Ca^(2+)show better performance in thesedimentation when compared with Na^(+),K^(+),Mg^(2+).The mechanism analysis shows that metal cations compress the electric double layer on the surface of montmorillonite,thus inhibit the hydration of montmorillonite,and are conducive to the agglomeration and sedimentation of montmorillonite.The research results have scientific significance for the treatment of montmorillonitecontaining coal slime water.