二价金属阳离子对沥青与二氧化硅表面间胶体作用力的影响  

Effect of Divalent Cation on the Interaction between Bitumen and Silica Surface

作　　者：张燕[1] ZHANG Yan(School of Traffic and Transportation,Lanzhou Jiaotong University,Lanzhou 730070,China)

机构地区：[1]兰州交通大学交通运输学院,兰州730070

出　　处：《兰州交通大学学报》2022年第1期116-122,共7页Journal of Lanzhou Jiaotong University

基　　金：甘肃省教育厅资助项目(2019A-045);甘肃省自然科学基金(20JR10RA227)。

摘　　要：为了从微观角度探索Ca^(2+)和Mg^(2+)对沥青水基提取过程的影响,在1 mmol/L KCl溶液中加入不同浓度的Ca^(2+)和Mg^(2+),调节pH值,采用原子力显微镜检测SiO_(2)与沥青表面间的胶体作用力.当溶液pH值分别为3.5,5.5和8.5时,随着Ca^(2+)或Mg^(2+)浓度的增加,沥青与SiO_(2)表面间的长程排斥力减小,表面电负性减弱;且Ca^(2+)和Mg^(2+)对沥青与SiO_(2)表面的电性能影响大小相似;二价阳离子在沥青与SiO_(2)表面间的静电吸附和选择性吸附是主要影响因素.当溶液pH值为10.5时,加入2.5 mmol/L的Ca^(2+)或Mg^(2+),沥青与SiO_(2)之间的长程排斥力减小,甚至在Mg^(2+)溶液中变为吸引力;Mg^(2+)对沥青与SiO_(2)表面间作用力的影响比Ca^(2+)大,是因为Mg^(2+)的溶度积比Ca^(2+)小.结果表明:SiO_(2)与沥青液滴的表面性能会受到二价金属阳离子的影响,因此在水基提取沥青过程中,为了提高沥青回收率,并获得高质量的泡沫,必须控制矿浆的pH值和矿浆中的二价阳离子浓度.In order to explore the influence of Ca^(2+) and Mg^(2+) on the water-based extraction process from the microscopic perspective,different concentrations of Ca^(2+) and Mg^(2+) were added into 1 mmol/L KCl solution to adjust the pH value,and the colloidal force between SiO_(2) and asphalt surface was detected by atomic force microscopy.When the pH value of solution is 3.5,5.5 and 8.5,the long range repulsion between asphalt and SiO_(2) surface decreases and the surface electronegativity weakens with the increase of Ca^(2+) or Mg^(2+) concentration,while the effects of Ca^(2+) and Mg^(2+) on the electrical properties of asphalt and SiO_(2) surface are similar.When the solution pH value is 10.5,adding 2.5 mmol/L Ca^(2+) or Mg^(2+),the long-term repulsion between asphalt and SiO_(2) decreases,and even becomes attractive in Mg^(2+)solution.The effect of Mg^(2+) on the surface interaction between asphalt and SiO_(2) is greater than that of Ca^(2+),because the solubility product of Mg^(2+) is smaller than that of Ca^(2+).The results show that the surface properties of SiO_(2) and asphalt droplets are affected by divalent metal cations.Therefore,in the process of water-based asphalt extraction,in order to improve the recovery rate of asphalt and obtain high-quality foam,it is necessary to control the pH value of pulp and the concentration of divalent cations in the pulp.The results show that the surface electrical properties of silica and bitumen droplets will be affected by divalent cations.Therefore,in order to improve the recovery rate of bitumen and obtain high quality foam,the pH value and the concentration of divalent cation in pulp must be controlled.

关 键 词：原子力显微镜 长程作用力 粘着力 钙离子 镁离子 

分 类 号：O647.11[理学—物理化学]