School of Chemical & Environment Engineering,China University of Mining & Technology(Beijing),Beijing　 100083,China

针对不同超细粉碎方式的作用特点,选用搅拌磨、气流磨、胶体磨、球磨,研究不同粉碎方式对超净煤分选效果的作用,发现采用胶体磨加工处理得到的超净煤产率最高为84.55%,灰分最低为0.83%,更有利于提高超净煤的分选效果。为了研究磨矿方式对超净煤分选效果促进作用的机理,通过粒度分布曲线和SEM研究超细粉碎方式对煤粒几何特征的作用,结果表明胶体磨加工处理后粒度分布均匀,细化充分有效避免了细粒再次聚团;煤粒表面没有明显的断裂,存在大量凹凸,尖角被钝化。通过AFM,FTIR和润湿热曲线研究不同超细粉碎对煤粒的表面化学性质的作用,AFM结果表明,胶体磨处理的煤样表面粗糙度最大,Rq=2.96 nm,高度变化较大,暴露更多的官能团,因此煤样解离更充分;FTIR结果表明胶体磨处理后煤样表面官能团含量发生显著变化,疏水基与亲水基吸收峰面积比值最大为0.084,煤样中的有机质和无机质更有效的解离,煤样疏水性改善;润湿热曲线表明胶体磨处理后煤样与非极性油有更强烈的作用,润湿热为1.384 J/kg,有利于煤粒形成结构紧实、选择性好的絮团。形成密实稳定选择性好的絮团,可以有效地提高超净煤的分选效果。

In this paper,in order to study the effect of various ultra-fine grinding modes on ultra-clean coal separation effect,taking the different characteristics of ultra-fine grinding methods into consideration,choosing stirring mill,air mill,colloid mill and ball mill for comparisons,the coal samples were processed by four ultra-fine grinding to product ultra-clean coal. The results show that the flotation could obtain the highest yield of 84． 55% and the lowest ash of 0． 83 by using colloid mill,thus the colloid mill is more conducive to improving the ultra-clean coal separation effect. In order to study the mechanism of the effect of grinding on the separation efficiency of ultra-clean coal,the effect of ultra-fine grinding on the geometrical characteristics of coal particles was obtained through the study of size distribution and SEM. The results show that when the coal was processed by colloid mill,its size distribution was uniform,refine- ment was detailed and the fine agglomerates were avoided,the coal particle surface had no obvious fractures,a lot of ir- regularities occurred and the sharp corners were blunted. The effect of ultra-fine grinding on the surface chemical prop- erties of coal particles was obtained through the study of AFM,FTIR and wet heat curves. After the processing of colloid mill,the AFM results show that the surface roughness (Rq ) of the coal sample had the highest value of 2. 96 nm,the change of height was the largest and more functional groups were exposed,that meant the coal sample was dis- sociated effectively. The results of FTIR show that the contents of functional groups on the surface of coal sample were changed significantly,the ratio of hydrophobic functional groups to hydrophilic functional groups absorption peak area was the biggest with a value 0. 084,that meant,the organic matters and the inorganic matters in coal samples were dis- sociated efficiently,and the hydrophobicity of coal samples were improved. The wetting and heat curves showed that the coal sample had a stronger effect with the non-polar oil,the value of wetting heat was 1. 384 J / kg,which was beneficial for fine particles to form floccules with tight structure and high selectivity. The formation of a compact,stable and se- lective floccule can effectively improve the separation efficiency of ultra-clean coals.

国家自然科学基金资助项目(51474211)；

Zhao Jing,Fu Xiaoheng,Wang Jie,et al. Influence of ultra-fine grinding mode on ultra-clean coal separation effect[ J]. Journal of China Coal Society,2016,41(12):3108-3114.