难浮煤表面性质及亲水性研究

Study on Surface Characteristics and Hydrophilicity of Difficult Floatation Coal

低阶煤、氧化煤等煤泥浮选提质困难,很大程度上影响了选煤厂生产效率的提高。为探明低阶煤、氧化煤的难浮特性,从煤的宏观物质组成到微观的表面形貌和化学基团,系统分析了难浮煤表面性质;结合接触角和诱导时间测试,阐明难浮煤的亲水特性。结果表明,难浮煤表面粗糙,含有大量孔隙和裂隙,高灰微细矿物易吸附在煤粒表面,恶化浮选过程;难浮煤表面含有大量的亲水性官能团,不利于煤颗粒上浮;接触角测量和表面自由能计算结果表明,难浮煤表面极性成分多,煤-水相互作用较强;诱导时间测试结果进一步说明了难浮煤颗粒-气泡诱导时间长,其表面具有很强的亲水性,浮选提质难。

Coal slime such as low rank coal or oxidized coal is difficult to be floated and upgraded,which greatly affects the improvement of production efficiency of coal preparation plants.In order to study the difficult floatation characteristics of low rank coal or oxidized coal,the surface characteristics of difficult floatation coal were systematically analyzed from the macroscopic compositions to the microscopic surface morphology and chemical groups.And the hydrophilic characteristics of difficult floatation coal were clarified by means of contact angle and induction time tests.The results showed that the surface of difficult floatation coal was rough and contained a large amount of pores and fractures,and the high-ash fine minerals easily adsorbed on the surface of coal particles,which worsen the floatation efficiency.A lot of hydrophilic functional groups in the surface of difficult floatation coal were not conducive to the floatation of coal particles.The calculation results of contact angle and surface free energy showed that there were a lot of polar components on the surface of difficult floatation coal,and the interaction between coal and water was strong.The test results of induction time further showed that the particle-bubble induction time of difficult floatation coal was long,its surface had strong hydrophilicity,and it was difficult to be floated and upgraded.