羧酸对低阶煤泥浮选的促进作用研究

Study on Promoting Effect of Carboxylic Acid on Flotation of Low-rank Coal

低阶煤表面含氧量高,表面疏水性差,柴油难以在煤表面高效吸附,药剂消耗量大,浮选效果不理想。将柴油与羧酸类的油酸、月桂酸、正癸酸、正辛酸复配对大同侏罗纪低阶煤进行浮选实验,基于煤样的表面性质对复配药剂的作用机理进行研究。结果表明:除正辛酸外,油酸、月桂酸、正癸酸的加入均会有效提高实验的浮选效果,油酸、月桂酸的提升效果最明显,相比于单独使用柴油在达到同等的浮选效果时节油率可达50%。此外油酸、月桂酸的加入可有效增加煤样表面的接触角,使煤样更疏水,正癸酸的效果弱于油酸与月桂酸。10%质量分数的四种羧酸与柴油的复配药剂中以油酸的复配药剂在矿浆中的分散粒径最小,月桂酸次之;且通过XPS分析,发现油酸的加入可有效增加煤样的C-C,C-H疏水性含氧官能团,降低C-O亲水性含氧官能团。药剂的分散性有效改善以及药剂作用后煤样的亲水性减弱,疏水性增强使浮选效果得到提升。

The surface oxygen content of low rank coal is high and the surface hydrophobicity is poor.It is difficult for diesel oil to adsorb on the coal surface efficiently.The reagent consumption is large and the flotation effect is not ideal.In this paper,diesel oil and carboxylic acid of oleic acid,lauric acid,decanoic acid and octanoic acid were combined to carry out flotation test on Datong Jurassic low rank coal.The results show that the addition of oleic acid,lauric acid and decanoic acid can effectively improve the flotation effect,and oleic acid and lauric acid have the most obvious effect.Compared with diesel oil alone,the oil rate can reach 50%.In addition,the addition of oleic acid and lauric acid can effectively increase the contact angle of coal sample surface and make the coal sample more hydrophobic.The effect of n-decanoic acid is weaker than that of oleic acid and lauric acid.Among the four carboxylic acids with 10%mass fraction and diesel oil,oleic acid has the smallest particle size in slurry,followed by lauric acid;and through XPS analysis,it is found that oleic acid can effectively increase the C-C,C-H hydrophobic oxygen-containing functional groups of coal samples,and reduce the C-O hydrophilic oxygen-containing functional groups.The dispersion of the reagent is improved effectively,and the hydrophilicity of the coal sample is weakened,and the hydrophobicity is enhanced,which improves the flotation effect.