煤泥水中黏土颗粒对钙离子的吸附实验研究及机理探讨

通过静态(搅拌)实验，研究了吸附时间、pH值、钙离子浓度等因素对钙离子在煤系黏土(主要为高岭土和蒙脱土)表面的吸附规律，实验结果表明：随着吸附时间的延长，钙离子在2种实验样品表面吸附量先不断增大而后趋于平衡；蒙脱土表面的钙离子吸附量随溶液pH值的升高而增加，高岭土表面钙离子的吸附量在溶液pH值介于6．5到7．0时最小，小于6．5时吸附量随pH值的增大而缓慢减小，大于7．0时吸附量随pH的增大而迅速增加；2种吸附过程都符合langmuir等温吸附规律．钙离子在样品表面3种可能的吸附形式为一羟基络合、Ca(OH)2沉淀和离子静电吸附．

Adsorption Properties and Mechanism of Calcium Ions on Clay Particle Surface in Coal Slurry

The adsorption properties of calcium ions on clay particle surface (such as kaolin and montmorillonite) in coal slurry under the influence of adsorption time, pH value, and calcium ion concentration were studied by static experiments. Experiment results show that adsorption amount of calcium ions increases gradually at the beginning and then tends to a constant as adsorption time increases. Two kinds of adsorption process follow the Langmuir adsorption isotherm. The adsorption amount of calcium ions on montmorillonite surface increases as pH value increases. To the adsorption amount of calcium ions on kaolin, when pH value is less than 6.5, the adsorption amount reduces as pH value increases; when pH value is greater than 7. 0, the amount increases rapidly as pH value increases; when pH value is between 6. 5 and 7. 0, the adsorption amount is the minimum. Experiment analysis also shows that hydroxy complexation, Ca(OH)2 precipitation and ion electrostatic adsorption are the three possible adsorption forms of calcium ion on sample surface.