湍流场中浮选颗粒-气泡脱附行为的尺寸效应研究  

Study on Size Effect of Flotation Particle-bubble Detachment Behavior in Turbulent Field

作　　者：史文庆 刘新宇[1,2] 丁世豪 尹青临 何琦[1,2] 曹亦俊 桂夏辉 邢耀文 SHI Wenqing;LIU Xinyu;DING Shihao;YIN Qinglin;HE Qi;CAO Yijun;GUI Xiahui;XING Yaowen(National Engineering Research Center of Coal Preparation and Purification,China University of Mining and Technology,Xuzhou 221116,China;School of Chemical Engineering and Technology,China University of Mining and Technology,Xuzhou 221116,China;School of Chemical Engineering,Zhengzhou University,Zhengzhou 450001,China)

机构地区：[1]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 [2]中国矿业大学化工学院,江苏徐州221116 [3]郑州大学化工学院,河南郑州450001

出　　处：《金属矿山》2023年第4期65-72,共8页Metal Mine

基　　金：国家自然科学基金面上项目(编号:21978318);国家重点研发计划项目(编号:2020YFC1908803)。

摘　　要：湍流诱发浮选颗粒-气泡脱附已达成广泛共识,但湍流场中颗粒的脱附行为机制仍未明晰。传统离心脱附理论认为当颗粒所受离心力大于毛细力时颗粒从气泡表面脱附,忽略了颗粒重力对浮选颗粒-气泡间稳定性的影响,且未考虑不同尺寸颗粒间的脱附行为差异。采用自制的微流体通道湍流槽探索了湍流涡中不同尺寸颗粒的脱附行为,运用Image-Pro Plus图像处理软件对颗粒脱附过程的动力学参数进行测量分析。结果表明,粗颗粒(2.0 mm)质量大,颗粒在气絮体升浮阶段发生直接脱附;而中颗粒(1.0 mm)和细颗粒(0.5 mm)质量小,气泡会带动颗粒由湍流槽底部向湍流涡中心旋转迁移,同时颗粒在气泡表面高速旋转发生离心脱附。此外,颗粒稳定性分析表明传统邦德(BO*)模型并不能对湍流场中的颗粒-气泡气絮体稳定性进行准确判断,颗粒易受湍流涡加速或气泡振荡的影响,导致颗粒脱附时邦德数在1左右波动。It has been well recognized that turbulence is the main reason inducing particle-bubble detachment in flotation,whereas the mechanism keeps unclear.The traditional centrifugal detachment theory suggests that when the centrifugal force of a particle is greater than its capillary force,the particle detaches from the bubble surface,excluding the influences of particle gravity and the disparate detachment behaviors of the particles with different sizes.The detachment behaviors of particles with different sizes in turbulent vortexes was studied by using a self-constructed microfluidic channel setup,and the kinetic parameters of particle detachment process were measured and analyzed by Image-Pro Plus.The results show that the coarse particles(2.0 mm)have a large mass,leading to the immediate detachment in the lifting stage.The mass of the middle particles(1.0 mm)and fine particles(0.5 mm)are much smaller,allowing the bubbles drive the particles to transfer and rotate from the bottom of the turbulent cell to the center of the turbulent vortex,and the particles′high rotating speed on the surface of the bubble introduce centrifugal detachment.In addition,the analysis of particle stability shows that the particles are easily affected by turbulent vortex acceleration or bubble oscillation,resulting in the fluctuation of Bond number around 1 during aggregate detachment,which means the Bond model can′t accurately judge the stability of particle-bubble aggregates in the turbulent field.

关 键 词：浮选 颗粒-气泡 湍流 离心脱附 颗粒尺寸 

分 类 号：TD923[矿业工程—选矿]