基于不同疏水性煤模型制备的气泡与煤表面黏附机制研究  

Study of mechanism of adhesion between bubble and coal particle surface using coal models prepared with different hydrophobicities

作　　者：朱春云 于锋 李明[1,2,3] 孙丽娟[1,2,3] 邢耀文 桂夏辉[1,2] ZHU Chunyun;YU Feng;LI Ming;SUN Lijuan;XING Yaowen;GUI Xiahui(State key Laboratory of Coking Coal Resources Green Exploitation,China University of Mining and Technology,Xuzhou 221116,China;National Engineering Research Center of Coal Preparation and Purification,China University of Mining and Technology,Xuzhou 221116,China;School of Chemical Engineering&Technology,China University of Mining and Techno-logy,Xuzhou 221116,China;Wuhai Energy Co.Ltd.,China National Energy Group,Wuhai 016000,China)

机构地区：[1]中国矿业大学炼焦煤资源绿色开发全国重点实验室,江苏徐州221116 [2]中国矿业大学国家煤加工与洁净化工程技术研究中心,江苏徐州221116 [3]中国矿业大学化工学院,江苏徐州221116 [4]国家能源集团乌海能源有限责任公司,内蒙古乌海016000

出　　处：《选煤技术》2024年第4期30-36,共7页Coal Preparation Technology

基　　金：国家自然科学基金面上项目(21978318,52274278)。

摘　　要：常规气泡探针研究中常采用云母、金片等作为矿物模型,难以准确反映煤样表面微纳结构与化学性质,进而难以充分反映气泡与煤表面间的黏附机制。为此,通过在二氧化硅表面旋涂沥青并进行不同时间的氧化处理,制备得到了化学性质与煤更相似且具有不同疏水性的煤模型;基于对制备得到的煤模型进行接触角测试、粗糙度测试、碰撞黏附行为的高速动态测试以及AFM气泡探针测试,明确了气泡与不同疏水性煤表面间的黏附机制。制备得到的强疏水性、中等疏水性、弱疏水性煤模型表面的静态接触角分别为95.19°,75.24°,55.23°,算术平方根粗糙度分别为0.29,0.46,0.43nm。宏观黏附行为中,流体力和表面力共同支配气泡与煤表面的相互作用过程;高速动态测试中,流体力强于表面力导致气泡与不同疏水性煤表面间碰撞次数无明显差异;准静态环境中,在表面力驱动下气泡与强疏水性煤表面间液膜于345ms破裂,与中等疏水性煤表面间液膜于845ms发生破裂,与弱疏水性煤表面间液膜则并未发生破裂。气泡探针测试中,驱动速度为1μm/s时,气泡与强疏水性煤表面在进针过程中斥力为23.08±3.93nN的位置处发生了跳入黏附,当驱动速度速度增加至10μm/s时,气泡与煤表面间黏附发生了滞后,而驱动速度增加至30μm/s时,黏附行为则被完全抑制;随着煤表面疏水性的降低,不同驱动速度下气泡均未发生黏附,仅在退针过程中测得引力且与驱动速度呈正相关;对于强疏水性煤表面,降低流体力有利于表面力驱动液膜薄化破裂从而促进黏附,而对于中等及弱疏水性煤表面,增加流体力则可增大颗粒与气泡远离过程中的流体倒吸引力从而有利于提高颗粒与气泡的黏附概率。The conventional bubble probing technique using mica or gold sheet as coal models cannot accurately reflect the coal specimen′s surface micronano structure and chemical property,thus making it difficult to bring to light the bubble-coal particle surface adhesion mechanism.To address this issue,the coal models are prepared with SiO2 which is coated with asphalt through rotodip process and oxidization treatment of different time periods.The models are similar to coal in chemical property and have different hydrophobic surfaces.Through testing on contact angles,roughness,high-speed dynamic test on collisional adhesion behavior,and AFM bubble probing,the mechanism of adhesion between bubble and coal particle with different hydrophobic surfaces is brought to light.As revealed by test results,the measured contact angles of the highly,moderately and weakly hydrophobic models′surfaces are 95.19°,75.24°,55.23°,respectively,with their respective arith-metic square root roughness being 0.29,0.46,0.43 nm.Viewed from the macro adhesion behaviors,the bubble-particle surface interaction process is jointly governed by hydrodynamic force and surface force;as shown by result of high-speed dynamic test,there shows no significant difference in the number of times of collisions between bubble and different coal surfaces as the surface force is shielded by hydrodynamic force;after the turn of environment to a quasi-static state,the liquid film between bubble and coal surface ruptures under the effect of driving of surface force at 345 ms for highly hydrophobic surface and at 845 ms for moderately hydrophobic surface,and no rupture of film is observed for the weakly hydrophobic surface.In the bubble probe test,at a driving speed of 1μm/s,the bubbles start to adhere to the highly hydrophobic surface at a repulsive force of 23.08±3.93 nN during the probe insertion process,but the adhesion process tends to lag behind with the in-crease of the driving speed to 10μm/s,and the adhesion behavior is seen to be completely suppressed a

关 键 词：煤泥浮选 黏附机制 煤模型制备 高速动态测试 AFM气泡探针测试 表面力 流体力 黏附概率 

分 类 号：TD943[矿业工程—选矿]