褐煤颗粒界面与煤泥水溶液相互作用机制

A Study on interaction mechanism between lignite particle interface and slime water

为掌握褐煤颗粒界面与煤泥水之间的相互作用规律,作者研究了褐煤颗粒在不同搅拌强度、浸泡时间以及不同粒度下对煤泥水溶液的pH值和电导率以及离子组成的影响,探讨了pH值、搅拌强度、浸泡时间、阳离子种类与浓度对褐煤颗粒表面Zeta电位以及含氧官能团的影响。结果表明,搅拌和浸泡使煤泥水溶液的pH值由弱酸性逐渐增大至中性,溶液电导率也逐渐增大,随着粒度的减小,悬浮液的酸性增强电导率增加。Zeta电位绝对值随着搅拌强度和pH值的增加总体呈上升趋势,浸泡使褐煤颗粒表面Zeta电位绝对值先减小后增大,当浸泡3 d时达到最小值,不同阳离子改变褐煤颗粒表面Zeta电位能力顺序为Al3+>Ca2+>Mg2+>Na+。搅拌使颗粒表面羧基和醇羟基含量增加,酚羟基含量先降低后增加,浸泡使羧基含量先降低后增加,而酚羟基和醇羟基含量逐渐增加。

In order to investigate the interactions rule between lignite particle interface and coal slurry solution,impact of lignite coal particles with different stirring intensity,immersing time and different particle size on coal slurry’s pH value,electrical conductibility and ion composition were studied,meanwhile,pH value,stirring intensity,immersing time,cation types and concentration impact on lignite coal particle surface Zeta potential and oxygen containing functional groups were also investigated. Results show that stirring and immersing process can gradually increase pH value of coal slurry from weakly acidic to neutral,and gradually increase solution’s electrical conductibility. With decreasing particle size, suspension gets acid enhancement and its electrical conductivity increase. Zeta potential absolute value shows overall upward trend with increasing stirring intensity and pH value.Immersing process decreases first then increases lignite coal particle surface Zeta potential absolute value,and the value touch its bottom when immersing time is 3 d. The order of lignite coal particle surface Zeta potential value that changed by different cation types is Al3+>Ca2+>Mg2+>Na+. Stirring process enlarges particle surface’s carboxyl and alcohol hydroxyl group content,while decreases first then increases phenolic hydroxyl group content. Immerging process decreases first then increases carboxyl group content,while hydroxyl group content gradually increases.