煤泥水的水化学性质对颗粒间相互作用有重要的影响。煤泥浮选需要煤颗粒与杂质颗粒在矿浆中充分分散，而煤泥水澄清需要颗粒有效凝聚。为解决浮选环节和澄清环节所需颗粒间分散-凝聚状态相矛盾的问题，以及所需水化学环境相矛盾的问题，以煤与高岭石颗粒为例，通过Zeta电位分布和原子力显微镜测力，从微观层面上研究了水化学性质对颗粒间作用行为的影响。金属离子对颗粒Zeta电位分布的影响研究表明，Ca2+使煤和高岭石颗粒各自的Zeta电位分布变窄，使同种颗粒间发生凝聚;Ca2+浓度由1 mmol/L增大到5 mmol/L时，煤与高岭石混合颗粒的Zeta电位分布由双峰变为单峰，煤与高岭石颗粒发生凝聚。Ca2+可以促进煤与高岭石颗粒间发生同类和异类凝聚，Na+对颗粒间凝聚行为的影响较小。用原子力显微镜直接测量颗粒间作用力，发现随着Ca2+浓度的增加，煤与高岭石颗粒间的作用斥力和作用范围逐渐减小，颗粒越来越容易发生凝聚，当Ca2+浓度增大到5 mmol/L时，煤和高岭石颗粒间出现引力;而Na+对颗粒间作用力的影响微弱。不同pH条件下颗粒间作用力的测试结果表明，随着pH值的减小，煤与高岭石之间的作用力由斥力转变为引力。通过原子力显微镜对煤颗粒间作用力的测定，发现煤颗粒间存在较强的疏水引力，同时表明，煤颗粒易发生同类凝聚，煤泥水澄清环节需重点考虑煤与黏土矿物颗粒、黏土矿物与黏土矿物颗粒的凝聚效果。

Water chemistry properties of coal slime water have an important influence on the interparticle interaction in coal preparation plant.Coal particles and impurity particles should be fully dispersed in the flotation process,and the clarification process of coal slime water requires particles to be effective coagulated.In order to solve the problem of the contradiction between the dispersion-coagulation state of particles required in the flotation process and clarification process,as well as the contradiction between the required water chemistry environment,the effect of water chemistry properties on the inter-particle interaction behavior between coal and kaolinite particles were studied at the micro level by Zeta potential distribution and atomic force microscope.Research on the influence of metal ions on the Zeta potential distribution of particles shows that Ca2+ can narrow the Zeta potential distributions of coal or kaolinite particles,causing particles homogeneous coagulation.When Ca2+ concentration increases from 1 mmol/L to 5 mmol/L,the Zeta potential distribution of the mixed coal-kaolinite changes from two peaks to one peak,indicating that coal and kaolinite particles coagulate.Therefore,Ca2+ can promote the homogeneous and heterogeneous coagulation of coal and kaolinite particles,while Na+has little effect on the coagulation of particles.The direct force measurement between particles was carried out using atomic force microscope.The repulsive force and interaction range between coal and kaolinite particles gradually decrease with the increase of concentration of Ca2+,and the particles are more and more prone to coagulation.When Ca2+ concentration increases to 5 mmol/L,an attractive force appears between the coal and kaolinite particles.However,Na+has no obvious effect on the interaction force between particles.The test results of interparticle forces under different pH conditions show that the interaction between coal and kaolinite changes from repulsion to attraction with the decrease of pH value.It is found that there is strong hydrophobic attraction between coal particles by measuring the force between two coal particles.It is also shown that coal particles are prone to homogeneous coagulation.Therefore,it is necessary to focus on the coagulation of coal-clay particles and clay-clay particles in the clarification process of coal slime water.The research can provide a theoretical guidance for the regulation of water chemistry properties in the flotation and clarification process,and is helpful to realize the efficient flotation and clarification cycle of coal slime water.

1 颗粒间相互作用

   1.1 颗粒的分散-凝聚行为

   1.2 颗粒间作用力

2 实验方法

   2.1 样品和试剂

   2.2 Zeta电位分布测定

   2.3 颗粒间作用力测定

3 结果与讨论

   3.1 水化学性质对颗粒Zeta电位分布的影响

   3.2 水化学性质对颗粒间作用力的影响

4 结论