摘要
充分了解浮选颗粒与气泡间相互作用过程,有助于指导浮选实际生产过程中表面活性剂的选择与气-液-固三相界面的调控。通过表面改性得到亲/疏水颗粒和固体基底,利用先进手段研究了气泡颗粒间微纳尺度下相互作用过程。结果表明:亲水颗粒包覆角仅能达到28.38°,疏水颗粒包覆角则随时间不断增加,900 s时可达到168.55°,说明提高颗粒疏水性可改善其可浮性。在相对运动方面,亲水颗粒在气泡表面滑移过程中,颗粒与气泡中心距离保持不变;疏水颗粒在气泡表面滑移过程中,出现瞬间“下陷”现象,此时颗粒气泡间液膜薄化破裂,推算出破裂液膜厚度约为0.01 mm。在相互作用力方面,气泡与亲水表面间不存在黏附引力,由斥力主导;气泡与疏水表面间出现“跳入”引力达到45.80μN,在接触瞬间液膜薄化破裂,破裂液膜厚度约为0.02 mm(~15.16μm)。AFM测试得到疏水颗粒与微米气泡间液膜破裂厚度为114.34 nm,此数值较颗粒与毫米级气泡间破裂液膜厚度相差2个数量级,说明颗粒气泡发生黏附作用时,破裂液膜厚度与气泡尺寸有关。
A full understanding of the interaction process between particles and bubbles is helpful to guide the selection of surfactants and the regulation of gas-liquid-solid three-phase interface in practical flotation.In this paper,hydrophilic/hydrophobic particles and solid substrates were prepared by surface modification,and the interaction between bubbles and particles was studied by some advanced means on a micro-nano scale.The results show that the coating angle of hydrophilic particles is only 28.38°,but that of hydrophobic particles can reach to 168.55°at 900 s,indicating that the floatability of particles increase with the improvement of hydrophobicity.In terms of the relative motion,the center distance between the hydrophilic particle and the bubble remains unchanged during the sliding process of the hydrophilic particle on the bubble surface.In contrary,the hydrophobic particles suddenly"jump in"the bubble surface during the sliding process,the liquid film between the particle and the bubble becomes thin and ruptured at this time.The thickness of the rupture liquid film is about 0.01 mm.In terms of interaction force,the adhesion force is not found between the bubble and the hydrophilic surface,which is dominated by repulsion.The obvious“jump-in”attachment force between the bubble and the hydrophobic surface is up to 45.80μN,and the liquid film is thinning during approaching and breaks suddenly at the moment of contact,the thickness of the rupture liquid film is about 0.02 mm(~15.16μm).AFM results show that the thickness of liquid film between hydrophobic particle and micro bubble is 114.34 nm,which is 2 orders of magnitude less than that between particles and millimeter bubbles.It indicates that the thickness of rupture liquid film is related to the size of bubble when particles adhere to bubbles.
作者
张凡凡
曹亦俊
邢耀文
桂夏辉
孙丽娟
杨海昌
李明
ZHANG Fanfan;CAO Yijun;XING Yaowen;GUI Xiahui;SUN Lijuan;YANG Haichang;LI Ming(School of Chemical Engineering and Technology,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)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2022年第S01期276-284,共9页
Journal of China Coal Society
基金
国家自然科学基金资助项目(51920105007,21978318,51974310)
关键词
颗粒
气泡
相互作用
跳入黏附
破裂液膜厚度
particle
bubble
interaction
“jump in”attachment
thickness of rupture fluid film
作者简介
张凡凡(1990—),女,江苏徐州人,博士研究生。E-mail:zhangfanfan@cumt.edu.cn;通讯作者:曹亦俊(1969—),男,山东淄博人,教授。E-mail:caoyj@cumt.edu.cn
