不同密度细粒煤泥对粗粒煤泥浮选的影响机理

分别将0.074 mm粒度以下的低密度(-1.4 g/cm3)、中间密度(1.4~1.8 g/cm3)和高密度(+1.8 g/cm3)细粒煤泥掺入到粗粒煤泥中进行浮选试验,研究不同密度细粒煤泥对粗粒煤泥浮选产率的影响,通过AFM测定低密度、高密度细粒煤泥颗粒与低灰粗颗粒煤之间的作用力,采用SEM观察浮选精煤、尾煤中粗颗粒煤的表面形貌,结合EDLVO理论对其影响机理进行了探讨。结果表明:中间密度细粒煤泥对粗粒煤泥浮选的抑制作用最大,低密度细粒煤泥次之,高密度细粒煤泥最小;粗粒煤泥的粒度越大,其浮选产率受中间密度细粒煤泥的影响越严重;AFM测定的作用力-距离曲线证实了疏水作用力的存在,颗粒疏水性越强,颗粒间的疏水力越大;通过SEM观察发现中间密度细粒煤泥在粗粒煤泥表面的罩盖现象显著。

Mechanism of the effect of fine coal with different densities on coarse coal flotation

Three fractions of different density (-1.4 g/cm3，1.4-1.8 g/cm3 and +1.8 g/cm3) fine coals sized -0.074 mm were separately mixed with the coarse coal sized +0.074 mm，and then a flotation experiment was carried out to study the effect of different density fine coals on coarse coal flotation.The interaction force between -1.4 g/cm3，+1.8 g/cm3 fine particle with the low ash coarse coal was identified separately by AFM.The concentrate and tailings were observed by SEM and the mechanisms were discussed through the extended DLVO theory.The results show that the middle fraction (1.4-1.8 g/cm3) greatly reduces the flotation recovery of the coarse coal，the fraction of -1.4 g/cm3 also has a depression on that of coarse coal，however，the fraction of +1.8 g/cm3 has less effect.The AFM test confirmed that the presence of hydrophobic force between two hydrophobic particles.The greater surface hydrophobicity，the larger hydrophobic forces.The SEM shows that middle fraction fine coal obviously covers the surface of coarse coal particles.