煤泥浮选过程中，颗粒与气泡的稳定黏附对颗粒能否被气泡成功捕集起着决定性的作用。经起泡剂改性后的气泡与低阶煤颗粒之间相互作用力的变化影响2者的黏附行为，起泡剂用量对低阶煤颗粒与改性后气泡间的微观作用机理尚未明晰。以鄂尔多斯地区不黏煤与经起泡剂(仲辛醇)改性前后的浮选气泡为研究对象，利用原子力显微镜探究了经不同浓度起泡剂改性后气泡与低阶煤颗粒之间相互作用力的变化规律，并利用分子模拟技术，对起泡剂在气液界面的微观作用机理进行揭示。最后，通过对颗粒-气泡间黏附效率的直接测定，从宏观尺度上对微纳尺度下的低阶煤颗粒-气泡间作用力的测量结果进行了直接验证。结果表明:气泡表面经起泡剂改性后，低阶煤颗粒与气泡接近过程中的“跳触”现象随着起泡剂浓度的增加而逐渐消失，2者的相互作用力也发生明显变化，随着起泡剂浓度的提高，颗粒-气泡间的黏附力显著减弱，甚至出现消失的趋势;低阶煤颗粒-气泡间的黏附效率也随之降低。分子动力学模拟表明，起泡剂在气液界面吸附时，起泡剂的亲水基团(—OH)与水分子形成的氢键，束缚了水分子在气泡表面的扩散运动，且随着起泡剂分子数量的增加，这种束缚作用更加强烈，因而大大降低气泡表面的疏水性。因此，起泡剂对气泡表面进行改性后，气泡表面疏水性的降低造成低阶煤颗粒-气泡间黏附力减弱，进而影响了2者的黏附行为。

The stable adhesion between particles and bubbles plays a decisive role in whether particles can be successfully trapped by bubbles in flotation process.The change of interaction force between bubbles modified by frother and low rank coal particles affects their adhesion behavior The influence mechanism of frother on the interaction between low-rank coal and bubbles is not clear yet.Non caking coal from Inner Mongolia and air bubbles modified by frothers (2-Octanol) are used as research objects.Atomic force microscopy (AFM) is used to probe the interaction force between low-rank coal and bubbles treated with different concentrations of frother.Molecular dynamics simulation is used to reveal the microscopic action mechanism of frother at the gas-liquid interface.Finally,by directly measuring the adhesion efficiency between particles and bubbles,the measurement results of the interforce between particles and bubbles at micro and nano scales are directly verified on a macro scale.The results show that the “jump contact” disappeared gradually with the increase of foaming agent concentration.The interaction force between low-rank coal particles and bubbles modified with frother also changes obviously.With the increase of the concentration of frother,the adhesion force between particles and bubbles weakens significantly,and even appears a tendency to disappear.The adhesion efficiency between particles and bubbles of low rank coal decreases accordingly.Molecular dynamics simulation showes that the hydrogen bond formed between the hydrophilic group (—OH)of frother and water molecules bound the diffusion movement of water molecules on the surface of bubbles when frother was adsorbed at the gas-liquid interface.With the increase of the number of frother molecules,the binding effect became more intense,thus greatly reducing the hydrophobicity of the surface of bubbles.Therefore,after the modification of bubble surface with frother,the reduction of hydrophobicity on bubble surface weakens the adhesion force between low-rank coal particles and bubbles,and then affects the adhesion behavior between them.

1 实验与材料

   1.1 实验材料

   1.2 实验方法

2 结果与讨论

   2.1 低阶煤颗粒与改性气泡间的相互作用力

   2.2 起泡剂在气液界面作用的微观机理

   2.3 低阶煤颗粒与改性气泡间的黏附效率

3 结论