To elucidate the microscopic mechanisms underlying the impact of hydrated cations on the surface hydration of slime mineral particles(specifically,kaolinite and quartz,the primary minerals in slime),this study focused on construct-ing two common hydrated cations in slime water:[Na(H2O)5]+ and[Ca(H2O)8]2+.Using density functional theory,the ad-sorption of these two hydrated cations on the surfaces of kaolinite(001),(00(-1))and α-quartz(001),as well as their compet-itive adsorption with water molecules were simulated.The simulation results revealed that the adsorption energy of hy-drated cations on all three surfaces was over 50%lower than that of water molecules.The adsorption stability on mineral surfaces was as follows:α-quartz(001)surface>kaolinite(001)surface>kaolinite(00(-1))surface.The adsorption energy of the competitively stable configuration was 34%-57%lower than that of a single hydrated cation on kaolinite and quartz.Additionally,the[Ca(H2O)8]2+ configuration exhibited a greater stability than the[Na(H2O)5]+ configuration under both adsorption conditions.When the hydrated cations adsorbed onto three surfaces,strong hydrogen bonds formed with sur-face,surpassing the strength of hydrogen bonds between water molecules and kaolinite/quartz surfaces.The hierarchy of hydrogen bonds between two hydrated cations on mineral surfaces was as follows:kaolinite(001)surface>α-quartz(001)surface>kaolinite(00(-1))surface.Under a competitive adsorption,the hydrogen bond between[Na(H2O)5]+ and mineral surface strengthened,while the bond between[Ca(H2O)8]2+ and mineral surface weakened.Although hydrogen bonding did not entirely correlate with changes in adsorption energy,electrostatic interactions in the adsorption configuration were identified.The electrostatic interaction in the single adsorption configuration of hydrated cations proved stronger than that in water molecular adsorption.Under a competitive adsorption,the electrostatic interactions between hydrated cations and mineral surfaces intensified,with[Ca(H2O)8]2+ demonstrating stronger interaction than[Na(H2O)5]+.Given the robust ad-sorption of hydrated cations on the surfaces of kaolinite and quartz,the dehydration of slime particles becomes more chal-lenging.This could increase hydration repulsion between particles,resulting in a more stable dispersion of particles in slime water.

To investigate the microscopic mechanism of CO2 adsorption on the M2+ (M = Fe, Ca, Mg)-doped kaolinite (denoted the M2+-Kao) (0 0 1) surface of low-priced metal cation, density functional theory (DFT) was employed to simulate CO2 adsorption on the perfect-phase kaolinite (denoted Kao) (0 0 1) surface and the M2+-Kao (0 0 1) surface. The results show that M2+ doping mainly enhances the activity of H atoms on the surface, and the order of CO2 adsorption on M2+-Kao (0 0 1) surface was Fe2+-Kao > Ca2+-Kao > Mg2+-Kao. The adsorption energy calculation results indicate that CO2 can be stably adsorbed on both the Kao (0 0 1) surface and the M2+-Kao (0 0 1) surface. The adsorption mechanism of CO2 on the M2+-Kao (0 0 1) surface involves the combined action of hydrogen bonding and electrostatic interactions, with the latter being the main contributor. The results provide valuable theoretical and technical insights for the preparation of clay-based CO2 mineralized functional materials.

To achieve efficient flocculation of fine montmorillonite particles, molecular simulation and flocculation test were investigated to explore the influence of cationic monomer on the performance of cationic polyacrylamide (CPAM) flocculating montmorillonite particles. Three cationic monomers including methylacryloxyethyl trimethyl ammonium chloride (DMC), acrylamide propyl trimethyl ammonium chloride (ATMAC), and methylacrylamide propyl trimethyl ammonium chloride (MAPTAC) were copolymerized with acrylamide (AM) to produce CPAM copolymers. The simulation results suggested the electrostatic interaction was the primary internal propelling force for the stable adsorption of three distinct CPAM copolymers on the montmorillonite/water interface, followed by hydrogen bonding. Flocculation test indicated that CPAM has better flocculation effect on fine montmorillonite particles only when it has strong electrostatic adsorption and bridging capacity. This research establishes a theoretical foundation for the structural design of new flocculants for fine clay minerals.

The origin of the difference in activity between calcined kaolinite and calcined montmorillonite is not well understood. Herein, reactive force field molecular dynamic (ReaxFF MD) simulations were adopted to study the thermal activation behavior of montmorillonite and kaolinite. It was found that during the calcination process, the removal of hydroxyl groups from kaolinite and montmorillonite not only leads to the break of Al (Mg)-O bonds, but also results in the formation of Si[5] and the break of Si-O bonds. The octahedral alumina sheet in kaolinite is more easily destroyed than that of montmorillonite. Most of the hydroxyl groups in kaolinite can be removed after calcination at 800 degrees C. While only 32.5% of the hydroxyl groups in montmorillonite are removed after calcination at 900 degrees C. The combination of free hydroxyl groups with Si[4] mainly causes the break of Si-O bonds in Si-O-Al(Mg) structure and the destruction of connection between the tetrahedral silica sheet and octahedral alumina sheet. While the Si-O-Si networks in both kaolinite and montmorillonite are difficult to disrupt. Disrupting the network structures of Si-O-Si sheet is the key to improving the activity of montmorillonite. This work provides an insight into the thermal activation of montmorillonite and kaolinite at atomic level, and is beneficial for exploring suitable pathways for simultaneous activation of kaolin and montmorillonite.

To enhance the filtration and dewatering performance while reducing the moisture content of coal preparation products, we conducted an investigation into the dehydration efficacy of various coal preparation products using different filter aids. The study involved examining the dehydration effects of both conventional filter aids and new filter aids on flotation cleaned coal and coarse fine slime at the Huaibei Linhuan coal preparation plant. Our findings revealed a significantly superior dehydration performance of the new filter aids compared to conventional hydrophobic ones. Subsequently, we explored the dehydration efficacy of a specific new filter aid, designated as 1239, on four types of coal samples sourced from the Huainan mining area. The results demonstrated that filter aid 1239 exhibited remarkable effectiveness on both flotation cleaned coal and coarse fine slime, with a discernible impact on coal slime as well. By modulating the hydrophobicity of particle surfaces, hydrophobic filter aids effectively facilitated the dehydration of coal preparation products. These findings bear substantial significance for improving the dewatering and transportation processes of coal preparation products.

To investigate the microscopic mechanism of CO2 adsorption on the M2+ (M = Fe, Ca, Mg)-doped kaolinite (denoted the M2+-Kao) (0 0 1) surface of low-priced metal cation, density functional theory (DFT) was employed to simulate CO2 adsorption on the perfect-phase kaolinite (denoted Kao) (0 0 1) surface and the M2+-Kao (0 0 1) surface. The results show that M2+ doping mainly enhances the activity of H atoms on the surface, and the order of CO2 adsorption on M2+-Kao (0 0 1) surface was Fe2+-Kao > Ca2+-Kao > Mg2+-Kao. The adsorption energy calculation results indicate that CO2 can be stably adsorbed on both the Kao (0 0 1) surface and the M2+-Kao (0 0 1) surface. The adsorption mechanism of CO2 on the M2+-Kao (0 0 1) surface involves the combined action of hydrogen bonding and electrostatic interactions, with the latter being the main contributor. The results provide valuable theoretical and technical insights for the preparation of clay-based CO2 mineralized functional materials.

In this work, a three-product slime flotation experiment was conducted utilizing a two-stage direct flotation method with the BS collector and dodecane reagent system to maximize the flotation efficiency and reduce the flotation tailings along with an increase in its ash content. Modern analytical methods, such as X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) were used for analyzing the surface characteristics of the samples and their interaction with collectors. The results demonstrated a significantly higher ash content of secondary flotation tail coal compared to the primary one with increasing reagent dose. Ash content for clean coal ranges from 8.00% to 9.00% when the overall net coal output surpasses 85%, and it rises to 30.00% to 50.00% for flotation tail coal. The surface hydration membrane and BS collector form a hydrogen bond through the -OH functional group, which results in increased hydrophobicity and effectiveness of flotation.

To investigate the changes in kaolinite surface hydration characteristics after Ca2+ substitution, water molecule adsorption onto the surface of Ca2+-substituted kaolinite was studied using density functional theory. Changes in the hydration film on the surface of kaolinite (001) and the mineral surface hydrophilicity after Ca2+ substitution were studied using molecular dynamics methods. Several Ca2+-substituted kaolinite samples were hydrothermally synthesized, and their hydration characteristics were analyzed using contact-angle and microcantilever humidity-test methods. The energy of a water molecule adsorbed on a Ca2+-substituted kaolinite surface is > 5 % lower than on pure kaolinite, and microscopic interactions between water molecules and the kaolinite surface are enhanced. Further, water molecules are more likely to be adsorbed onto the (00(1)over bar) surface than the (001) surface of kaolinite. After Ca2+ substitution, the hydration film on the kaolinite (001) surface becomes denser and the hydrophilicity of the mineral surface is enhanced. Using X-ray diffraction, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy to characterize the synthesized samples, we confirmed successful Ca2+ substitution within the kaolinite structure. Hydration-test results showed that the surface hydrophilicity of kaolinite is enhanced after Ca2+ substitution and increases with increasing Ca2+ substitution. The experimental results thus verified the simulations.

To explore the microscopic effects of Mg(II) doping amount on the hydration characteristics of kaolinite surface, the Mg(II) ions and kaolinite were used as the subjects of research in molecular dynamics simulations and experimental verification to investigate the microscopic effects of the lattice magnesium impurity on the surface hydration of kaolinite. The results indicate that the interaction between H2O and Mg(II)-doped kaolinite (Mg(II)-Kao) surfaces, along with hydrogen bonding at the interface, gradually increase with increasing Mg(II) doping amounts, implying that Mg(II) doping significantly enhance the surface hydration of kaolinite. The hydration of the Mg(II)-doped kaolinite (001) surface (Mg(II)-Kao(001)) is stronger than that of the Mg(II)-doped kaolinite (001¯) surface (Mg(II)-Kao(001¯)) with the same Mg(II) doping amount. As the quantity of Mg(II) doping increased, the contact angle and humidity of the kaolinite surface decrease and progressively increase, respectively, signifying that the hydration level of the kaolinite surface increase. Overall, the main influence of Mg(II) doping on the surface hydration properties of kaolinite is the enhancement of hydration activity and ionic hydration. The results can provide theoretical support for further study of the real clay surface hydration mechanism, efficient treatment of clay-containing mineral processing wastewater and resource utilization of coal measure clay.

The interaction between fine particles is widespread in nature and plays a crucial role in regulating various interfaces for minerals. In coal preparation wastewater treatment, the intricate mechanism of interaction between multi-component fine particles in coal slurry water (denoted as CSW) is a fundamental aspect in addressing the challenges of coal slurry water agglomeration, selective separation, and difficult dewatering. This paper presents a summary of the necessity, current research status, and progress in studying the microscopic interaction between mineral particles in CSW systems. It overviews theoretical calculation formulas for particle-particle interaction, factors that influence such interaction, and modern analysis techniques for studying microscopic particle interaction. These findings enhance and refine relevant theories, establish a theoretical foundation, and offer technical support for stabilizing and optimizing the performance of CSW systems. Additionally, it elucidates the mechanism of particle-particle interaction in CSW, which is of significant importance in achieving efficient separation of CSW.

Froth flotation, as one of the most widely used separation approaches in mineral processing, is commonly used to recover valuable components from minerals. However, maintaining high flotation efficiencies is a serious challenge for conventional froth flotation in the face of decreasing particle size of the minerals to be sorted. To date, there have been plenty of reports on the software of nano-bubbles (NBS) in flotation, and the experimental consequences show that nano-bubbles' introduction has given rise to improvement's different grades in the recovery of varieties of minerals, which highlights the great potential of nano-bubbles for mineral flotation. Nanobubbles have smaller bubble radii and unusually high stability compared to conventional flotation bubbles, and their related behavior in flotation has been a hot research topic. This paper reviews some of the methods of preparing nanobubbles, equipment techniques for characterizing nanobubbles, factors affecting their stability, and some of the popular doctrines. In particular, the reinforcing mechanism of nanobubbles in the particle flotation process is discussed, first, the nanobubbles improve the electrostatic attractiveness with the particles by achieving the charge inversion while the nanobubbles that was adsorbed on the particles' surface will cover a share of the charge, which decreases the electrostatic repulsive force between the particles; and second, the nanobubbles can act as a bridge between the surfaces of the two particles, which advances the agglomeration between the particles. This review aims to be able to further advance the research related to the industrialization of nanobubbles.

The interaction between chitosan and kaolinite has an important influence on the performance of their composites, the adsorption mechanism of chitosan onto kaolinite surface was investigated by density functional theory (DFT) calculation. The results show that the adsorption energies of chitosan have significant difference on different kaolinite surfaces, but has few difference at different sites on the same kaolinite surface. Chitosan structural unit can interact stablely with kaolinite (001) surface through two strong hydrogen bonds and two moderately strong hydrgeon bonds, and the hydrgeon bond formed between the N atom of chitosan and H atom of hydroxyl group is the strongest. However, the interaction between chitosan and kaolinite(001¯) surface is through two weak hydrogen bonds between the H(N-H, O-H) atoms on chitosan and O atoms on kaolinite(001¯) surface. The structural difference between kaolinite (001) and (001¯) surface is the main reason for the obvious difference in their interaction with chitosan.

To investigate the effect of Fe(II/III) doping on the microscopic mechanism of methylamine salt hydrophobic modifiers on kaolinite surfaces, the adsorption characteristics of various methylamine cations on Fe(II/III)-doped kaolinite (denoted as Fe(II/III)-Kao) surfaces are calculated by density functional theory (DFT). The simulation results, including the Fukui index, adsorption energy, Mulliken bond populations, and charge analysis, reveal that Fe(II/III) doping enhances the surface activity of kaolinite, with significant effects observed in proximity to the doping site. Consequently, Fe(II/III) doping strengthens the interaction between methylamine cations and kaolinite surfaces. The adsorption mechanism of various methylamine cations on Fe(II/III)-Kao surfaces is attributed to a combination of hydrogen bonding and electrostatic attraction, with electrostatic attraction dominating the adsorption process. By comparing the adsorption energy of methylamine cations and alkyl carbon chains on Fe(II/III)-Kao surfaces, it becomes evident that the alkyl carbon chain has minimal impact on the adsorption of the hydrophobic modifier on Fe(II/III)-Kao surfaces. This finding confirms that the ammonium salt hydrophobic modifier primarily adsorbs onto Fe(II/III)-Kao surfaces through its polar head groups. The research results establish a theoretical foundation for further investigations on fine clay particle interface control and hydrophobic modifier design, ultimately guiding practical production processes.

为探究Fe2+掺杂对十二胺分子(DDA)及其阳离子(DDA+)在高岭石层面吸附的微观影响机制,对DDA和DDA+在Fe2+掺杂高岭石(001)及(001)面的吸附进行了密度泛函理论(DFT)计算.结果表明:DDA和DDA+在Fe2+掺杂高岭石层面的吸附机理为氢键和范德华静电引力共同作用.DDA在Fe2+掺杂高岭石层面吸附以氢键作用为主,范德华静电引力作用为辅;DDA+在Fe2+掺杂高岭石层面吸附以范德华静电引力作用为主,氢键作用为辅.Fe2+的杂质缺陷增强了高岭石(001)面的表面活性,对(001)面的表面活性影响较小.研究结果可为进一步研究煤泥水中黏土颗粒表面的真实吸附状态及煤泥水高效处理药剂的设计提供理论依据.

To research the adsorption mechanism of single H2O on the surface of Fe-doped kaolinite (named Fe-kao), the adsorption process was simulated using the density functional theory (DFT) method. The analysis demonstrated that the adsorption of a single H2O on the Fe-kao surface is more stable than that on the ideal kaolinite surface. Additionally, it can be deduced that the most stable H2O adsorption occurs on the Fe(III)-Na-doped kaolinite (named Fe(III)-Na-kao) (001) surface. The adsorption of single H2O on Fe-kao surfaces relies heavily on hydrogen bonding and electrostatic attraction. Simultaneously, Fe-kao samples were synthesized by hydrothermal synthesis, and synthesized samples were tested by the Mo center dot ssbauer spectrum and capillary ascent method. The results show that the Fe element is successfully doped into the kaolinite lattice, and Fe doping heightens the surface hydration characteristics of kaolinite, which is similar to the simulation results. The outcomes will offer theoretical backing for slime water ensuing dewatering and sedimentation.

Alkali fusion of granite sawdust at a high alkali dosage can significantly improve geopolymerization activity, but also result in a high alkali consumption and a poor geopolymer performance. In this work, quartz, the most inert component in granite sawdust, was selected to explore the effect of low-alkali activation on its reactivity and the compressive strength of geopolymer. It was found that the amount of activated quartz is mainly determined by the amount of alkali used for activation. The surface of a quartz particle can be effectively activated by an alkali fusion process at a low alkali dosage of 5%. The metakaolin-based geopolymer synthesized with quartz activated by an alkali dosage of 5% shows a high compressive strength of 41 MPa, which can be attributed to the enhanced interfacial interaction between quartz and the geopolymer gel, suggesting that low-alkali activation is a potential way to improve the geopolymerization ability of granite sawdust.

This paper focuses on the influence of reagent interaction on induction time in the process of bubble-particle interaction. Induction time instrument was used to investigate the influence of single reagent and reagent interaction on induction time. Meanwhile, the influence mechanism of reagent interaction on coal particle surface wettability, surface tension, and surface functional groups was studied combined with contact angle and FTIR. The results showed that when the collector interacted with the frother, the addition of the frother reduced the induction time and increased the hydrophobicity of the coal particle surface. Compared with raw coal, the surface contact angle of collectorfrother-reacted coal particles increased, and its change law was inconsistent with that of collector-reacted coal particles. The larger the contact angle, the lower the surface tension, the higher the interfacial surface tension between coal particles and water, the lower the wettability and the more hydrophobic the particle surface. FTIR spectra indicated that the influence of collector-frother interaction on the surface functional groups of coal particles was mainly reflected in the absorption peaks at 3436 cm(-1) and 1400 similar to 1000 cm(-1). The effect of interaction varied with the structure of the reagent. 2-Octanol can produce multi-point adsorption on the surface of coal particles and promote the hydrophobic modification of coal particle surface. When ether alcohols interacted with arene, reverse adsorption occurred. Throughout this study, the mechanism affecting the adhesion characteristics of coal particles and bubbles caused by reagent interaction was clarified.

To investigate the micro-influence mechanism of Fe(II) doping on the surface hydration of kaolinite, molecular dynamics (MD) simulation method was utilized to simulate the interaction between H2O and Fe(II)-doped kaolinite (referred to as Fe(II)-Kao) surface under different conditions. Results demonstrate that the H2O can be adsorbed on Fe(II)-Kao surfaces, forming a hydration film composed of three H2O layers with a thickness of 8-10 & ANGS;. As the thickness of the H2O layer increased on Fe(II)-Kao surfaces, the interfacial effect between H2O and the surface gradually weakened. Furthermore, the interaction between H2O and Fe(II)-Kao (001) surface is weaker compared to that on the Fe(II)-Kao (001) surface. Additionally, the presence of Fe(II) doping enhanced the hydration of the kaolinite surface. The micro-influence mechanism of Fe(II) doping on the surface hydration of kaolinite can be attributed to the enhancement of the interface effect between equilibrium cations (such as Na (I)) and the surface, resulting in an increased ion hydration at the kaolinite surface. Overall, Fe(II) doping tends to promote the surface hydration of kaolinite. The elucidated mechanism of how impurity defects affect the surface hydration activity of kaolinite can provide theoretical support for tailings separation and wastewater treatment.

In order to explore the influence mechanism of Ca 2+ substitution on the crystal structure and surface properties of kaolinite, the cell model of Ca 2+ substituted kaolinite was constructed, and the bond length, bond angle, band structure and density of states, surface frontier orbit, Fukui index and charge were analyzed by density functional theory. The simulation results show that after substitution, the cell conductivity is enhanced and the reaction activity is stronger. The Na + equilibrium configuration is more stable than the K + equilibrium configuration. On the ■ planes, the surface reactivity of kaolinite after substitution is enhanced, in which the reactivity of H1 and O3 sites is enhanced, while water molecules tend to be adsorbed on the（001） plane more than on the ■ plane. Combined with the surface charge distribution, the electronegativity of substituted kaolinite（001） surface is enhanced, and the electrostatic interaction between Na + and（001） surface or ■ surface is dominated. Ca 2+ replaces Al 3+ , resulting in local expansion of the crystal and changes in the surrounding lattice structure. At the same time, the orbital energy and charge density change with the change of orbital electron distribution, and finally change the reaction activity.

To explore the influence of alcohol/ether alcohol frother on the flotation efficiency of common collector dodecane, the molecular dynamics simulation method was used to study the influence of the type and concentration of frother on the microscopic interaction mechanism between the collector and the coal surface, which was verified by the flotation test. The research shows that in a single reagent system, weak hydrogen bond was the main way of interaction between polar groups of two frothers and oxygen-containing functional groups on coal surface The hydrogen bond effect in ether alcohol system was stronger than that in 2-ctanol system, and the dispersion force between the carbon chain of the reagent and the coal surface was stronger when ether alcohol was adsorbed on the coal surface. In the mixed reagent system, both kinds of frothers can promote dodecane spreading on the coal surface for adsorption, and the synergism of ether alcohol was better. The dodecane can promote the adsorption of polar groups of ether alcohol on the coal surface while the ether alcohol formed weak hydrogen bonds with the coal surface, thus increasing the hydrophobic modification of the polar groups on the coal surface. Excessive frother concentration would reduce the hydrophobicity of the coal surface, which was accompanied by poor adsorption of the reagent. The flotation verification test results were consistent with the regularity obtained from molecular dynamics simulation. The research provides theoretical guidance for the development of flotation reagents from the micro level.