基于蒙脱石分散行为解析钙离子对煤泥水沉降性能的影响  

Effect of Calcium Ion on Montmorillonite Particle Behavior and Coal Slurry Settling

作　　者：张明青[1] 宋烁烁 景宏涛 ZHANG Mingqing;SONG Shuoshuo;JING Hongtao(School of Environmental Science&Spatial Informatics,China University of Mining and Technology,Xuzhou 221000,China)

机构地区：[1]中国矿业大学环境与测绘学院,江苏徐州221000

出　　处：《太原理工大学学报》2022年第5期830-837,共8页Journal of Taiyuan University of Technology

基　　金：国家自然科学基金资助项目(51874304)。

摘　　要：蒙脱石在水中会发生晶层集合体分散和晶层剥离两个过程,通过添加钙离子改善煤泥水沉降性能的相关研究还未涉及这两个过程。在煤系蒙脱石水化分散初期、中期和分散完成三个时间点添加钙离子制成三种分散体系,分析三种体系中颗粒的粒度分布、Zeta电位分布和体系黏度的变化规律,计算颗粒表面水化指数,并借助冷冻扫描电镜观察颗粒在溶液中的形貌特征,研究钙离子对蒙脱石分散和体系沉降性能的影响。结果表明:在分散初期添加钙离子可使蒙脱土保持沉积态大颗粒状,不出现荷电量高的40μm以下颗粒,体系黏度低,沉降性能良好,钙离子抑制颗粒晶层剥离是体系沉降性能改善的主要原因;分散完成后添加钙离子,颗粒电动电位降低,但体系中微细颗粒占比没有降低,体系沉降性能改善不明显,钙离子作用机理主要为压缩双电层。水化分散中期添加钙离子的体系中各项参数介于上述两种体系之间,沉降性能改善不及初期添加钙离子体系。钙离子对实际煤泥水沉降性能的影响与对蒙脱石体系的规律一致。The hydration and dispersion of clay in coal determine the sedimentation performance of coal slurry.In this paper,calcium ions were added three times at the initial,mid-stage,and completion points of the hydration and dispersion of montmorillonite from coal bed,to make three dispersion systems.Some parameters of the three systems including particle size distribution,Zeta potential distribution,system viscosity changes,surface hydration index,and morphological characteristics were analyzed.The effects of calcium ions on the sedimentation performance of montmorillonite were tested.The results show that the addition of calcium ions at the initial stage of dispersion can keep montmorillonite in a large particle state,without high-charged particles below 40μm,low viscosity of the system,and good sedimentation performance.Calcium ions inhibit particle hydration and dispersion,which improves the sedimentation performance of the system.The main reason:when calcium ions are added after the dispersion is completed,the electrokinetic potential of particles is significantly reduced,but the proportion of fine particles in the system changes a little,and the sedimentation performance of the system is not significantly improved.The action mechanism of calcium ions is mainly to compress the electric double layers.The parameters of the calcium ion system added in the mid-stage of hydration and dispersion are between the above two systems,and the improvement in sedimentation performance is not as good as the initial addition system.The effect of calcium ions on the sedimentation performance of actual coal slurry is consistent with the law of montmorillonite system.

关 键 词：蒙脱石 煤泥水 沉降性能 钙离子 分散抑制 

分 类 号：TD934.4[矿业工程—选矿]