金属阳离子影响捕收剂粘附细粒煤的机制研究

Study on the mechanism of metal cations affecting collector adhesion to fine coal

提高煤的浮选效率是提高煤炭清洁利用率的重要途径之一,矿浆中的金属离子对浮选效率有显著影响。试验利用高速运动摄像系统,结合分子动力学模拟手段探究了不同金属离子种类及浓度对煤油在矿物表面粘附的影响机制。结果表明,金属离子存在的条件下,油滴在石墨表面振荡消耗时间顺序为:NaCl<MgCl_(2)<AlCl_(3)。在离子浓度为10^(-2) mol/L时,形成三相接触线的速度顺序:AlCl_(3)<MgCl_(2)<NaCl。油滴的等效直径随NaCl和MgCl 2浓度的增加而增加,当浓度到达10^(-2) mol/L后,随离子浓度的增加油滴的当量直径减小。分子动力学模拟的结果表明,Na^(+)的水化能力最弱,油滴接触角最小,而Al^(3+)接触角最大。适当添加NaCl和MgCl_(2)可以显著提高石墨精矿的回收率,而添加AlCl_(3)会出现抑制浮选效率的现象。试验结果旨在丰富浮选调浆理论,为提高浮选效率提供有价值的参考。

Improving the flotation efficiency of coal is one of the important ways to improve the clean utilization rate of coal.The metal ions in the pulp have a significant effect on the flotation efficiency.In this experiment,the influence mechanism of different metal ion types and concentrations on the adhesion of kerosene on mineral surface was investigated by using high-speed motion camera system and molecular dynamics simulation.The results show that in the presence of metal ions,the oscillation consumption time of oil droplets on the graphite surface is in the order of NaCl<MgCl_(2)<AlCl_(3).When the ion concentration is 10^(-2) mol/L,the speed order of forming three-phase contact line is AlCl_(3)<MgCl_(2)<NaCl.The equivalent diameter of oil droplets increases with the increase of NaCl and MgCl_(2) concentration.When the concentration reaches 10^(-2) mol/L,the equivalent diameter of oil droplets decreases with the increase of ion concentration.The results of molecular dynamics simulation show that the hydration ability of Na+is the weakest,the contact angle of oil droplets is the smallest,and the contact angle of Al 3+is the largest.Appropriate addition of NaCl and MgCl_(2) can significantly improve the recovery rate of graphite concentrate,while the addition of AlCl_(3) will inhibit the flotation efficiency.The experimental results are aimed at enriching the theory of flotation pulp conditioning and providing valuable reference for improving flotation efficiency.