1.School of Chemical Engineering and Technology,China University of Mining and Technology,Xuzhou　 221116,China;2． National Engineering Research Center of Coal Preparation and Purification,Xuzhou　 221116,China

煤泥浮选中,煤的可浮性与其表面润湿性质密切相关,选用表面润湿性差异较大的褐煤和焦煤为对象,研究气泡与煤炭表面碰撞过程中的三相接触周边的形成过程。分析了两种煤炭界面性质的差异,并采用I-SPEED 3高速动态摄像机记录并分析气泡与煤炭表面碰撞和黏附的微观过程。结果表明,在一定的碰撞速度条件下,气泡和煤炭表面要经过"接触—弹回—再接触"的数次碰撞过程,并最终形成气液固三相接触周边。焦煤表面与气泡经过2次碰撞后形成的铺展面积为8.2 mm~2,而褐煤表面的三相接触周边形成之前经过了3次碰撞,且气泡在其表面的最终铺展面积为4.6 mm~2。煤炭表面的接触角越大,三相接触周边形成的时间就越短,气泡在煤炭表面的铺展面积也越大,这从微观角度验证了浮选过程中煤炭表面疏水性对气泡矿化过程的影响。

In slime flotation,the flotation of coal is closely related to its surface wettability. In this paper,the lignite and coking coals with different surface wettability are investigated. The formation process of the three phases contact during the collision between bubble and coal surface is studied. First,the differences of the two kinds of coal interface properties are analyzed. At the same time,the I-SPEED 3 high speed dynamic camera is used to record and analyze the micro process of the collision and adhesion between air bubble and coal surface. Results show that under a certain con- dition of collision velocity,the bubble and coal surface should go through several collision process,contact-bounce-con- tact,and finally form the gas-liquid-solid three phase contact periphery. Three-phase contact surrounding is formed in the coking coal surface with bubble after the second collision,and the area is 8． 2 mm2 . Three-phase contact surround- ing is formed after 3 times of collision in the surface of lignite,and the bubble in coal surface spreading area is 4． 6 mm2 . The greater contact angle of coal surface is,the shorter the three-phase contact formed around the time will be, and the greater bubble in the spreading area of coal surface will be. From the microscopic point of view,the effect of surface hydrophobicity of coal on the process of bubble mineralization is verified.

国家自然科学基金资助项目(51504254,51274198)；中央高校基本科研业务费专项资金资助项目(2015XKMS039)；

Li Guosheng,Han Jiazhan,Deng Lijun,et al. Collision and adhesion process of air bubbles on coal surface[J]. Journal of China Coal Soci- ety,2016,41(11):2841-2846.