Anisotropic surface broken bond densities of six different surfaces of calcite and three surfaces of fluorite were calculated. In terms of the calculated results, the commonly exposed surfaces of the two minerals were...Anisotropic surface broken bond densities of six different surfaces of calcite and three surfaces of fluorite were calculated. In terms of the calculated results, the commonly exposed surfaces of the two minerals were predicted and the relations between surface broken bonds densities and surface energies were analyzed. Then the anisotropic wettability of the commonly exposed surfaces was studied by means of contact angle measurement. The calculation results show that the （101^-4）, （213^-4）and （01 1^-8）surfaces for calcite and （111） for fluorite are the most commonly exposed surfaces and there is a good rectilinear relation between surface broken bond density and surface energy with correlation of determination （R^2） of 0.9613 and 0.9969, respectively. The anisotropic wettability of different surfaces after immersing in distilled water and sodium oleate solutions at different concentrations can be explained by anisotropic surface broken bond densities and active Ca sites densities, respectively.展开更多
Surface energies of five different surfaces of scheelite crystal were calculated using density functional theory （DFT）. Based on the calculation results, the predominantly exposed surfaces in the morphologies of sch...Surface energies of five different surfaces of scheelite crystal were calculated using density functional theory （DFT）. Based on the calculation results, the predominantly exposed surfaces in the morphologies of scheelite crystals were predicted. {112} and {001} cleavage surfaces and {112} crystal surface are the commonly exposed surfaces, which are consistent with both previous literatures and the present experimental observations based on the XRD. Cleavage generates more easily along {112} surfaces than along {001} surfaces due to their different interlayer spacings. The surface roughness and appearance of different predominantly exposed surfaces were then investigated using AFM. The roughness of smooth {112} cleavage surface is the lowest among these three surfaces. On {001} cleavage surface, terraces are flat and separated by steps of about 10 nm in height. Subsequently, contact angle measurements were adopted to evaluate the wettability and surface energies of these surfaces. The surface energies evaluated directly correspond to the trend calculated with DFT.展开更多
The modification of Shenfu coals by a microwave treatment carried out under a hydrogen or a methane atmosphere, and the subsequent maceral separation by flotation, are described in this paper. The surface contact angl...The modification of Shenfu coals by a microwave treatment carried out under a hydrogen or a methane atmosphere, and the subsequent maceral separation by flotation, are described in this paper. The surface contact angle and the Zeta potential of the coal macerals were measured both with and without the treat- ment. The results show that the surface wettability of SFF (Shenfu Fusain) and SFV (Shenfu Vitrain) can be changed by the microwave treatment. An increase in the difference in surface wettability of SFF and SFV causes in a subsequent increase in the enrichment of inertinite and vitrinite. The results of the Zeta potential measurements show that the surface potentials of SFF and SFV are also changed by the treatment.展开更多
To reveal the potential effect of surfactant on improving surface wettability of copper ore,the droplet spreading behavior of sulfuric acid solution contained surfactant was visualized using high-speed camera and an i...To reveal the potential effect of surfactant on improving surface wettability of copper ore,the droplet spreading behavior of sulfuric acid solution contained surfactant was visualized using high-speed camera and an image processing method,and the solid-liquid interaction was discussed in this study.The results show that liquid surface tension and ore surface roughness are the main factors affecting surface wettability.The effect of sulfuric acid solution concentration and surfactants on the surface wettability of ore is revealed via quantitative spreading area,spreading coefficient,and contact angle.The results of droplet spreading experiment show that the higher concentration of surfactant and sulfuric acid solution result in improving the wettability of ore,spreading coefficient,and decreasing contact angle.The“leaching reaction coefficient”and“surface activity coefficient”are introduced to modify the mathematical expression of the equilibrium contact angle.展开更多
The wettability of the solid surface is often characterized by the contact angle of the liquid on the solid surface. However, it has long been found that the contact angle of liquid on a solid surface can take a range...The wettability of the solid surface is often characterized by the contact angle of the liquid on the solid surface. However, it has long been found that the contact angle of liquid on a solid surface can take a range of values between two extremes： the advancing and the receding contact angles. The difference between the advancing and the receding contact angles is conventionally called contact angle hysteresis. Knowledge of contact angle hysteresis is essential to understand surface wettability and control surface wetting behavior. The wettability can be affected, for example, by the roughness of the solid surface. In our work, textile is used as macroscopic roughness surfaces, and smooth plate surface is used as well to determine contact angle hysteresis. The advancing and receding contact angles are measured on polyamide materials.展开更多
基金Project (50834006) supported by the National Natural Science Foundation of ChinaProject (CX2011B122) supported by Hunan Provincial Innovation Foundation for PostgraduateProject (2011ybjz045) supported by Graduate Degree Thesis Innovation Foundation of Central South University
文摘Anisotropic surface broken bond densities of six different surfaces of calcite and three surfaces of fluorite were calculated. In terms of the calculated results, the commonly exposed surfaces of the two minerals were predicted and the relations between surface broken bonds densities and surface energies were analyzed. Then the anisotropic wettability of the commonly exposed surfaces was studied by means of contact angle measurement. The calculation results show that the （101^-4）, （213^-4）and （01 1^-8）surfaces for calcite and （111） for fluorite are the most commonly exposed surfaces and there is a good rectilinear relation between surface broken bond density and surface energy with correlation of determination （R^2） of 0.9613 and 0.9969, respectively. The anisotropic wettability of different surfaces after immersing in distilled water and sodium oleate solutions at different concentrations can be explained by anisotropic surface broken bond densities and active Ca sites densities, respectively.
基金Project(50831006)supported by the National Natural Science Foundation of ChinaProject(CX2011B122)supported by Hunan Provincial Innovation Foundation for Postgraduate,ChinaProject(2012BAB10B05)supported by the National Key Technologies R&D Program of China
文摘Surface energies of five different surfaces of scheelite crystal were calculated using density functional theory （DFT）. Based on the calculation results, the predominantly exposed surfaces in the morphologies of scheelite crystals were predicted. {112} and {001} cleavage surfaces and {112} crystal surface are the commonly exposed surfaces, which are consistent with both previous literatures and the present experimental observations based on the XRD. Cleavage generates more easily along {112} surfaces than along {001} surfaces due to their different interlayer spacings. The surface roughness and appearance of different predominantly exposed surfaces were then investigated using AFM. The roughness of smooth {112} cleavage surface is the lowest among these three surfaces. On {001} cleavage surface, terraces are flat and separated by steps of about 10 nm in height. Subsequently, contact angle measurements were adopted to evaluate the wettability and surface energies of these surfaces. The surface energies evaluated directly correspond to the trend calculated with DFT.
基金support provided by theShanxi Province "13115" Science and Technology Innovation Program (No. 2008ZDKG-53)the Shanxi International Scienceand Technology Cooperation Project of China (No. 2007KW-02)
文摘The modification of Shenfu coals by a microwave treatment carried out under a hydrogen or a methane atmosphere, and the subsequent maceral separation by flotation, are described in this paper. The surface contact angle and the Zeta potential of the coal macerals were measured both with and without the treat- ment. The results show that the surface wettability of SFF (Shenfu Fusain) and SFV (Shenfu Vitrain) can be changed by the microwave treatment. An increase in the difference in surface wettability of SFF and SFV causes in a subsequent increase in the enrichment of inertinite and vitrinite. The results of the Zeta potential measurements show that the surface potentials of SFF and SFV are also changed by the treatment.
基金Project(LJ2020JCL002)supported by Education Commission of Liaoning Province,ChinaProject(51604138)supported by the National Natural Science Foundation of China。
文摘To reveal the potential effect of surfactant on improving surface wettability of copper ore,the droplet spreading behavior of sulfuric acid solution contained surfactant was visualized using high-speed camera and an image processing method,and the solid-liquid interaction was discussed in this study.The results show that liquid surface tension and ore surface roughness are the main factors affecting surface wettability.The effect of sulfuric acid solution concentration and surfactants on the surface wettability of ore is revealed via quantitative spreading area,spreading coefficient,and contact angle.The results of droplet spreading experiment show that the higher concentration of surfactant and sulfuric acid solution result in improving the wettability of ore,spreading coefficient,and decreasing contact angle.The“leaching reaction coefficient”and“surface activity coefficient”are introduced to modify the mathematical expression of the equilibrium contact angle.
文摘The wettability of the solid surface is often characterized by the contact angle of the liquid on the solid surface. However, it has long been found that the contact angle of liquid on a solid surface can take a range of values between two extremes： the advancing and the receding contact angles. The difference between the advancing and the receding contact angles is conventionally called contact angle hysteresis. Knowledge of contact angle hysteresis is essential to understand surface wettability and control surface wetting behavior. The wettability can be affected, for example, by the roughness of the solid surface. In our work, textile is used as macroscopic roughness surfaces, and smooth plate surface is used as well to determine contact angle hysteresis. The advancing and receding contact angles are measured on polyamide materials.
