School of Material Science and Engineering,Anhui University of Science and Technology

低阶煤泥浮选过程中,由于其表面疏水性差,烃类油捕收剂能否顺利吸附在其表面,对最终的浮选效果具有重要影响。为强化烃类油捕收剂在低阶煤表面的吸附,采用理论计算、分子模拟和试验分析方法研究了高剪切调浆对低阶煤泥浮选的影响规律和强化机理。通过吸附量测试和理论计算研究了正十二烷油滴在煤颗粒表面的吸附规律;借助分子动力学模拟方法构建了正十二烷-水-低阶煤模拟体系,探索了正十二烷与煤表面的初始距离对最终吸附结果的影响;通过开展高剪切调浆浮选试验研究了叶轮转速对浮选精煤产率和灰分的影响规律。结果表明,高剪切调浆可显著提高捕收剂正十二烷在低阶煤表面的吸附量,当叶轮转速超2000r/min时,吸附量增幅逐渐降低,最终吸附量趋于稳定;正十二烷油滴与煤颗粒之间存在一个能垒,越过能垒后,总势能迅速降低;初始状态下正十二烷油滴与低阶煤表面的距离对最终模拟平衡结果有重要影响,初始距离较近时,油滴可在煤表面吸附并铺展,而初始距离较远时,则无法吸附;高剪切调浆可显著改善低阶煤的浮选效果,调浆叶轮转速为2000r时,浮选精煤产率增加了近13%,而灰分基本保持不变。

In the flotation process of low rank coal, the adsorption behavior of collector on the particle surface has an important impact onthe final flotation results. In order to strengthen the adsorption of oil collector on the surface of low rank coal, the strengthening mechanismof high intense condition on the flotation of low rank coal were investigated using theoretical calculation, molecular simulation and experimental analysis. The adsorption process of n-dodecane oil droplet on coal particle surface was studied by adsorption test and theoretical calculation. Collector - water - coal simulation system was constructed, and the influence of the initial distance between collectorand coal surface on the final adsorption results was explored. The effect of impeller speed on the yield and ash content of clean coal wasstudied. The results show that the adsorption capacity of n-dodecane on the surface of low rank coal can be significantly increased by highshear mixing. When the impeller speed exceeds 2 000 r/ min, the increase in adsorption gradually diminishes, reaching a stable level. Anenergy barrier exists between the n-dodecane oil droplet and the coal particle. After crossing the energy barrier, the total potential energy decreases rapidly. The initial distance between n-dodecane oil droplet and low rank coal surface has an important influence on the final simulation results. When the initial distance is closer, droplets can adsorb and spread on the coal surface, whereas a greater initial distance prevents adsorption. High-shear pulping significantly improves the flotation performance of low-rank coal. The yield of clean coal increasedabout 13% by high intense condition method compared with that of conventional flotation, while the ash content remains basically unchanged.

国家自然科学基金资助项目(52104241);中国博士后基金资助项目(2019M652163);安徽省博士后基金资助项目(2019B338)

乔二乐,闵凡飞,沈亮,等.高剪切调浆强化低阶煤泥浮选及其作用机理[J].洁净煤技术,2023,29(12):136-144.

QIAO Erle,MIN Fanfei,SHEN Liang,et al.High-shear condition for enhancing flotation of low rank coal and the associated mechanisms[J].Clean Coal Technology,2023,29(12):136-144.