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.

乔二乐(1988—),女,山西太原人,硕士研究生。E-mail:shen654520@aust.edu.cn

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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.