低阶煤浮选捕收剂及其作用机理研究进展

Advances in Flotation Collectors of Low-rank Coal and Its Interaction Mechanism

低阶煤约占我国主体能源煤炭的57%,其洁净高效加工利用对煤炭行业落实国家“双碳”目标具有重要意义。浮选是处理细粒(-0.5 mm)低阶煤最为有效的方法。但因低阶煤天然可浮性差、浮选捕收剂消耗量大等难题,其工业化至今未能实现。为了降低低阶煤浮选捕收剂消耗量,提高其浮选性能,综述了非离子型、离子型和复配型表面活性剂类捕收剂,探讨并总结了其与煤表面的作用机理。表面活性剂类捕收剂主要通过氢键作用、静电吸附等与煤粒表面作用。非离子表面活性剂类捕收剂中苯环的存在有助于其极性基团中极性氧原子在低阶煤表面的吸附;离子表面活性剂类捕收剂对煤表面酚羟基的掩蔽作用强于羧基;复配表面活性剂类捕收剂的吸附是由表面活性剂与煤表面之间的静电与氢键作用、药剂长链对煤表面极性基团的覆盖作用、不同捕收剂之间的协同作用共同实现的。捕收剂的乳化有助于提高药剂的分散效果,复配表面活性剂形成的活性油泡可作用于煤表面的特定部位(疏水和亲水位点),明显提高药剂的选择性和黏附强度,降低低阶煤浮选药剂消耗量。

It is of great significance for the coal industry to implement the Chinese strategic goals of the Carbon Peak and Carbon Neutrality by cleanly and efficiently separating low-rank coal,which accounting for about 57%of China′s coal reserves.Flotation is the most effective method for treating fine-grained(-0.5 mm)low-rank coal.However,due to the poor natural floatability of low-rank coal and the high consumption of flotation collectors,its industrialization has not yet been achieved.In order to reduce the consumption of flotation collectors of low-rank coal and improve their flotation performance,the non-ionic,ionic,and composite surfactants were reviewed.The interaction mechanisms between coal surfaces and reagents were explored and summarized.Surfactants mainly interact with the surface of coal particles through hydrogen bonding,electrostatic adsorption,etc.The adsorption of polar oxygen atoms in their polar groups on the surface of low-rank coal is facilitated in the presence of benzene rings for non-ionic surfactants.For ionic surfactants,a stronger masking effect on phenolic hydroxyl groups on coal surface is existed than carboxyl groups.The adsorption of composite surfactants is achieved by the electrostatic and hydrogen bonding interactions between surfactants and coal surfaces,the covering effect of long chain reagents on polar groups on coal surfaces,and the synergistic effect between different collectors.The emulsification of the collector helps to improve the dispersion of the reagents.The reactive oily bubbles formed by the composite surfactant can interact on specific parts of the coal surface(hydrophobic and hydrophilic sites).Then,the selectivity of collectors and the adhesion strength of the reagents is improved significantly,and the consumption of collectors for low-rank coal is also reduced.