Pub Date : 2025-02-01DOI: 10.1016/j.powtec.2025.120716
Jiawei Wang , Longxu Zhou , Suinian Liu , Zhongcheng Deng , Zhao Cao , Pei Li
This article proposes an advanced calibration technique for contact parameters in ball mill DEM simulations, introducing 3 innovations. First, the friction coefficients between particles and grinding media are calibrated using the draw down test, accurately reflecting dynamic contact characteristics. Second, the coefficient of restitution is derived by combining both non-fracture and fracture conditions, using weighted calculations based on the distribution of fracture energy. Third, the minimum impact energy is defined using Tavares-King's damage-fracture model, setting it at the energy level that causes the cumulative fracture probability of the fine particle to exceed 50 % after 10 impacts, thereby avoiding meaningless data in the collision energy spectrum. These innovations may enhance DEM simulation accuracy by providing a more realistic mechanical environment for ball milling, laying a solid foundation for the application of the advanced comminution model.
{"title":"An advanced calibration technique for contact parameters in ball milling DEM simulations","authors":"Jiawei Wang , Longxu Zhou , Suinian Liu , Zhongcheng Deng , Zhao Cao , Pei Li","doi":"10.1016/j.powtec.2025.120716","DOIUrl":"10.1016/j.powtec.2025.120716","url":null,"abstract":"<div><div>This article proposes an advanced calibration technique for contact parameters in ball mill DEM simulations, introducing 3 innovations. First, the friction coefficients between particles and grinding media are calibrated using the draw down test, accurately reflecting dynamic contact characteristics. Second, the coefficient of restitution is derived by combining both non-fracture and fracture conditions, using weighted calculations based on the distribution of fracture energy. Third, the minimum impact energy is defined using Tavares-King's damage-fracture model, setting it at the energy level that causes the cumulative fracture probability of the fine particle to exceed 50 % after 10 impacts, thereby avoiding meaningless data in the collision energy spectrum. These innovations may enhance DEM simulation accuracy by providing a more realistic mechanical environment for ball milling, laying a solid foundation for the application of the advanced comminution model.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"454 ","pages":"Article 120716"},"PeriodicalIF":4.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143103821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.powtec.2025.120708
Xi Chen, Shuyan Wang, Nuo Ding, Baoli Shao, Xuewen Wang, Yimei Ma
K2CO3 is widely recognized as an effective CO2 capture material due to excellent adsorption performance and reaction activity. In this study, the second-order moment (SOM) model is employed to simulate the CO2 adsorption with K2CO3 sorbents in a fluidized bed reactor, considering the effect of particle velocity fluctuation anisotropy. The results indicate that the anisotropy can enhance the heterogeneous reaction and improve the CO2 conversion rate in the reactor. Compared to the kinetic theory of granular flow (KTGF) model, the SOM model is better verified with the experimental results and can more accurately capture flow field heterogeneity and anisotropic characteristics. Quantities such as the particle concentration, velocities, particle second-order moments, Reynolds stresses, temperature and reaction characteristics are presented. Within a specific range, a higher temperature can intensify particle fluctuations and anisotropy, concurrently enhancing both reaction rates and CO2 conversion rates. These findings provide theoretical insights for optimizing process conditions in CO2 capture within fluidized bed reactors.
{"title":"Study of the CO2 absorption with K2CO3 sorbents in gas-solid fluidized beds based on second-order moment model","authors":"Xi Chen, Shuyan Wang, Nuo Ding, Baoli Shao, Xuewen Wang, Yimei Ma","doi":"10.1016/j.powtec.2025.120708","DOIUrl":"10.1016/j.powtec.2025.120708","url":null,"abstract":"<div><div>K<sub>2</sub>CO<sub>3</sub> is widely recognized as an effective CO<sub>2</sub> capture material due to excellent adsorption performance and reaction activity. In this study, the second-order moment (SOM) model is employed to simulate the CO<sub>2</sub> adsorption with K<sub>2</sub>CO<sub>3</sub> sorbents in a fluidized bed reactor, considering the effect of particle velocity fluctuation anisotropy. The results indicate that the anisotropy can enhance the heterogeneous reaction and improve the CO<sub>2</sub> conversion rate in the reactor. Compared to the kinetic theory of granular flow (KTGF) model, the SOM model is better verified with the experimental results and can more accurately capture flow field heterogeneity and anisotropic characteristics. Quantities such as the particle concentration, velocities, particle second-order moments, Reynolds stresses, temperature and reaction characteristics are presented. Within a specific range, a higher temperature can intensify particle fluctuations and anisotropy, concurrently enhancing both reaction rates and CO<sub>2</sub> conversion rates. These findings provide theoretical insights for optimizing process conditions in CO<sub>2</sub> capture within fluidized bed reactors.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"454 ","pages":"Article 120708"},"PeriodicalIF":4.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143103820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.powtec.2025.120702
Jin Hou , Botao Qin , Qun Zhou
This paper investigated the dynamic wetting characteristics during droplet impact on spherical particle as the main monitoring object, and analyzed the effects of droplet impact velocity, and surface tension on droplet spreading coefficient (Dc) and particle force. The droplet-particle collision condensation test platform designed and constructed in this paper. In addition, a novel particle-droplet collision numerical model was constructed by combining VOF, dynamic mesh and mesh adaptation techniques to assist the research. The results shown that the rate of increase of Dc increased with the increase of the collision velocity. When the collision velocity was less than 1 m/s, the attraction force generated by droplet on particle was greater than the resistance generated by surface tension, which results in adsorption force. The resistance of droplet to particle increased with the increase of velocity, while the effect of adsorption decreased. When the collision velocity exceeded 1 m/s, the effect of adsorption force was negligible, the particle and droplet could not produce adsorption mode of bonding and need to overcome the surface tension for wrapping. Reducing the surface tension could increase the encapsulation speed of the droplet to the particle, for example, the droplet with a surface tension of 28mN/m took only half as long as the surface tension of 76mN/m. The results of this study provide a basic theoretical basis for further exploration of the particle-droplet collision and coalescence mechanism.
{"title":"Investigation on spreading behavior and influencing parameters of particle-droplet collision","authors":"Jin Hou , Botao Qin , Qun Zhou","doi":"10.1016/j.powtec.2025.120702","DOIUrl":"10.1016/j.powtec.2025.120702","url":null,"abstract":"<div><div>This paper investigated the dynamic wetting characteristics during droplet impact on spherical particle as the main monitoring object, and analyzed the effects of droplet impact velocity, and surface tension on droplet spreading coefficient (Dc) and particle force. The droplet-particle collision condensation test platform designed and constructed in this paper. In addition, a novel particle-droplet collision numerical model was constructed by combining VOF, dynamic mesh and mesh adaptation techniques to assist the research. The results shown that the rate of increase of Dc increased with the increase of the collision velocity. When the collision velocity was less than 1 m/s, the attraction force generated by droplet on particle was greater than the resistance generated by surface tension, which results in adsorption force. The resistance of droplet to particle increased with the increase of velocity, while the effect of adsorption decreased. When the collision velocity exceeded 1 m/s, the effect of adsorption force was negligible, the particle and droplet could not produce adsorption mode of bonding and need to overcome the surface tension for wrapping. Reducing the surface tension could increase the encapsulation speed of the droplet to the particle, for example, the droplet with a surface tension of 28mN/m took only half as long as the surface tension of 76mN/m. The results of this study provide a basic theoretical basis for further exploration of the particle-droplet collision and coalescence mechanism.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"454 ","pages":"Article 120702"},"PeriodicalIF":4.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-31DOI: 10.1016/j.powtec.2025.120703
Zachary Diermyer , Yidong Xia , Ahmed Hamed , Jordan Klinger , Vicki Thompson , Zhen Li , Jiaoyan Li
Mechanical size reduction is a critical pretreatment for hydrometallurgical recovery of valuable metals in electronic waste. The particle size resulting from milling ranges from a few micrometers to a few millimeters, presenting challenges of achieving sufficient leaching percolation in portions occupied by fine particles. This work investigates the hydrodynamics of percolation through micrometer-sized fine particle beds by using many-body dissipative particle dynamics flow simulations. The results show that higher effective pore size resulting from high aspect-ratio particle packing contributes to higher permeability than spherical particle packing. Increasing surface wettability enhances maximum saturation rates but reduces permeability. Moreover, increasing tortuosity negatively impacts permeability and the degree of reduction in permeability caused by increased surface wettability decreases with increasing tortuosity. These findings imply possible complex relationships between tortuosity, pore size, and surface wettability that collectively impact percolation in loosely packed fine particle beds and can be used to guide improvement in pretreatment.
{"title":"Mesoscopic flow simulation to understand the percolation through fine-ground electronic waste particle bed","authors":"Zachary Diermyer , Yidong Xia , Ahmed Hamed , Jordan Klinger , Vicki Thompson , Zhen Li , Jiaoyan Li","doi":"10.1016/j.powtec.2025.120703","DOIUrl":"10.1016/j.powtec.2025.120703","url":null,"abstract":"<div><div>Mechanical size reduction is a critical pretreatment for hydrometallurgical recovery of valuable metals in electronic waste. The particle size resulting from milling ranges from a few micrometers to a few millimeters, presenting challenges of achieving sufficient leaching percolation in portions occupied by fine particles. This work investigates the hydrodynamics of percolation through micrometer-sized fine particle beds by using many-body dissipative particle dynamics flow simulations. The results show that higher effective pore size resulting from high aspect-ratio particle packing contributes to higher permeability than spherical particle packing. Increasing surface wettability enhances maximum saturation rates but reduces permeability. Moreover, increasing tortuosity negatively impacts permeability and the degree of reduction in permeability caused by increased surface wettability decreases with increasing tortuosity. These findings imply possible complex relationships between tortuosity, pore size, and surface wettability that collectively impact percolation in loosely packed fine particle beds and can be used to guide improvement in pretreatment.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"454 ","pages":"Article 120703"},"PeriodicalIF":4.5,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-30DOI: 10.1016/j.powtec.2025.120726
Yanan Chen , Jiaxin Jing , Liang Ma , Shenggui Ma , Yongpeng Diao , Kai Zheng , Jianping Li , Xia Jiang , Hualin Wang , Pengbo Fu
Fine particulate matter (PM2.5) is difficult to separate due to its small particle size, the microchannel separator demonstrates excellent separation performance, while structural design and bed regeneration are the difficulties. In this study, the velocity and pressure drop in the axial and radial microchannel separator were compared by computational fluid dynamics—discrete element method coupling model (CFD-EDEM), and the effects of different structural parameters on the separation performance were explored in depth experimentally to enhance the separation of PM2.5. The results show that the radial microchannel separator wins by having a lower pressure drop, giving it a significant advantage in energy consumption. The average PM2.5 removal efficiency of the radial microchannel separator is as high as 97.17 % and a pressure drop of only 1.76 kPa. Moreover, the in-situ regeneration efficiency of granular bed medium can reach 63.48 %. This study provides an essential reference for the purification of PM2.5 in high temperature smoke and the optimization of the structural parameters of the microchannel separator.
{"title":"Structural optimization of a radial microchannel separator applied to the filtration of PM2.5","authors":"Yanan Chen , Jiaxin Jing , Liang Ma , Shenggui Ma , Yongpeng Diao , Kai Zheng , Jianping Li , Xia Jiang , Hualin Wang , Pengbo Fu","doi":"10.1016/j.powtec.2025.120726","DOIUrl":"10.1016/j.powtec.2025.120726","url":null,"abstract":"<div><div>Fine particulate matter (PM<sub>2.5</sub>) is difficult to separate due to its small particle size, the microchannel separator demonstrates excellent separation performance, while structural design and bed regeneration are the difficulties. In this study, the velocity and pressure drop in the axial and radial microchannel separator were compared by computational fluid dynamics—discrete element method coupling model (CFD-EDEM), and the effects of different structural parameters on the separation performance were explored in depth experimentally to enhance the separation of PM<sub>2.5</sub>. The results show that the radial microchannel separator wins by having a lower pressure drop, giving it a significant advantage in energy consumption. The average PM<sub>2.5</sub> removal efficiency of the radial microchannel separator is as high as 97.17 % and a pressure drop of only 1.76 kPa. Moreover, the in-situ regeneration efficiency of granular bed medium can reach 63.48 %. This study provides an essential reference for the purification of PM<sub>2.5</sub> in high temperature smoke and the optimization of the structural parameters of the microchannel separator.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"454 ","pages":"Article 120726"},"PeriodicalIF":4.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-30DOI: 10.1016/j.powtec.2025.120713
Leiming Wang , Liang Cheng , Shenghua Yin , Wei Chen , Hongjie Li , Shuo Li , Chao Zhang
In this paper, the evolution and fractal characteristics of the pore structure of sandstone uranium ore after leaching under various temperature conditions were systematically studied mainly by using mercury intrusion porosimetry(MIP) method, low-temperature nitrogen adsorption(LTNA) method and scanning electron microscopy(SEM). The results show that the nitrogen adsorption and mercury intake of the ore under 40 °C leaching conditions are the largest, the volume of the pores is more prominent, and the pore structure is more developed compared with other leaching conditions. Calculating the fractal dimension through various models shows that the fractal dimension of the leached ore under certain temperature conditions is smaller than that under room temperature conditions, indicating that the ore's complexity decreases when leaching the ore under certain temperature conditions. The pore complexity of the ore is the lowest under the leaching condition of 40 °C, which is favorable for the flow of the solution. This study helps to understand the impact of temperature on ore pore structure during in-situ leaching, which is crucial for optimizing the process, improving uranium recovery, and ensuring sustainable resource use.
{"title":"Pore structure evolution and fractal characteristics of sandstone uranium ore under different leaching temperatures","authors":"Leiming Wang , Liang Cheng , Shenghua Yin , Wei Chen , Hongjie Li , Shuo Li , Chao Zhang","doi":"10.1016/j.powtec.2025.120713","DOIUrl":"10.1016/j.powtec.2025.120713","url":null,"abstract":"<div><div>In this paper, the evolution and fractal characteristics of the pore structure of sandstone uranium ore after leaching under various temperature conditions were systematically studied mainly by using mercury intrusion porosimetry(MIP) method, low-temperature nitrogen adsorption(LTNA) method and scanning electron microscopy(SEM). The results show that the nitrogen adsorption and mercury intake of the ore under 40 °C leaching conditions are the largest, the volume of the pores is more prominent, and the pore structure is more developed compared with other leaching conditions. Calculating the fractal dimension through various models shows that the fractal dimension of the leached ore under certain temperature conditions is smaller than that under room temperature conditions, indicating that the ore's complexity decreases when leaching the ore under certain temperature conditions. The pore complexity of the ore is the lowest under the leaching condition of 40 °C, which is favorable for the flow of the solution. This study helps to understand the impact of temperature on ore pore structure during in-situ leaching, which is crucial for optimizing the process, improving uranium recovery, and ensuring sustainable resource use.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"454 ","pages":"Article 120713"},"PeriodicalIF":4.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Composite fuels based on various wastes are a promising alternative to conventional energy resources. Co-combustion of waste-derived components is characterized by synergistic effects that have a significant impact on combustion performance. This paper presents the results of an experimental study of thermal decomposition characteristics and combustion kinetic parameters for composite fuels based on typical lignite, coal refinery waste, sawdust and used motor oil. Thermogravimetric analysis revealed the influence of individual component properties on the characteristics of their combined thermal oxidation in mixtures. The experiments were carried out in a temperature range of 25–1100 °C, corresponding to industrial combustion chambers. Conditions were identified that ensure significantly higher rates of thermal conversion of fuel mixtures than those of individual components. The influence of heating rate on thermal decomposition of mixed fuels was determined. The dependences of the activation energy of thermal decomposition on the content of volatiles and carbon, as well as ash content and humidity, were obtained. The experiments have shown the conditions under which the size of solid particles, their hydrophilicity and hydrophobicity have a significant influence on the characteristics of the thermal oxidation of fuels. Mathematical expressions were obtained for calculating kinetic characteristics of thermal oxidation of different types of coal using the known properties of the components.
{"title":"Kinetics of thermal oxidation of coals, industrial wastes, and their mixtures","authors":"Vadim Dorokhov , Geniy Kuznetsov , Kristina Paushkina , Pavel Strizhak","doi":"10.1016/j.powtec.2025.120712","DOIUrl":"10.1016/j.powtec.2025.120712","url":null,"abstract":"<div><div>Composite fuels based on various wastes are a promising alternative to conventional energy resources. Co-combustion of waste-derived components is characterized by synergistic effects that have a significant impact on combustion performance. This paper presents the results of an experimental study of thermal decomposition characteristics and combustion kinetic parameters for composite fuels based on typical lignite, coal refinery waste, sawdust and used motor oil. Thermogravimetric analysis revealed the influence of individual component properties on the characteristics of their combined thermal oxidation in mixtures. The experiments were carried out in a temperature range of 25–1100 °C, corresponding to industrial combustion chambers. Conditions were identified that ensure significantly higher rates of thermal conversion of fuel mixtures than those of individual components. The influence of heating rate on thermal decomposition of mixed fuels was determined. The dependences of the activation energy of thermal decomposition on the content of volatiles and carbon, as well as ash content and humidity, were obtained. The experiments have shown the conditions under which the size of solid particles, their hydrophilicity and hydrophobicity have a significant influence on the characteristics of the thermal oxidation of fuels. Mathematical expressions were obtained for calculating kinetic characteristics of thermal oxidation of different types of coal using the known properties of the components.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"454 ","pages":"Article 120712"},"PeriodicalIF":4.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-29DOI: 10.1016/j.powtec.2025.120700
Haruhisa Kato, Ayako Nakamura
Understanding the dispersing mechanism of particles in aqueous phase using a surfactant is key to the effective preparation of particle suspensions. In this study, the mechanism was elucidated using dynamic light scattering, pulse field gradient nuclear magnetic resonance spectroscopy, and electrophoretic mobility measurements. In this research, calcium carbonate particle suspensions with a particle concentration of 0.2 mg mL−1 (0.0074 vol%) were created in water through ultrasonication, utilizing polyoxyethylene alkylether (Softanol-70) as the stabilizing surfactant. When dispersing particles in an aqueous phase using a surfactant, the concentration of surfactant that was not adsorbed on the particles was affected by the micellar size. When the surfactant concentration was relatively higher (above 0.2 mg mL−1), prolonged ultrasonication enabled the particles to reach and retain their smallest size by preventing re-agglomeration. This was due to the sufficient presence of non-adsorbed surfactant, which stabilized the micelle size. Conversely, at lower surfactant concentrations (less than 0.15 mg mL−1), short ultrasonic irradiation reduced particle sizes in the liquid phase; however, extending the ultrasonication duration led to re-agglomeration of the particles. The latter phenomenon was induced by the reduction of the micellar size of the surfactant from approximately 8 nm to 2–1 nm, which was related to the reduction of the amount of non-adsorbed surfactant on the particles. Interestingly, the zeta potential of the dispersing particles remained almost unchanged at approximately −24 mV during the dispersing process. This indicated that electrostatic repulsion between particles was not a significant factor in this particle suspension, whereas the micellar size of the surfactant was an important key. This finding could significantly contribute to the effective preparation of a particle suspension.
{"title":"Effect of surfactant concentration on dispersing mechanism of aqueous particle/surfactant suspension system prepared by ultrasonication","authors":"Haruhisa Kato, Ayako Nakamura","doi":"10.1016/j.powtec.2025.120700","DOIUrl":"10.1016/j.powtec.2025.120700","url":null,"abstract":"<div><div>Understanding the dispersing mechanism of particles in aqueous phase using a surfactant is key to the effective preparation of particle suspensions. In this study, the mechanism was elucidated using dynamic light scattering, pulse field gradient nuclear magnetic resonance spectroscopy, and electrophoretic mobility measurements. In this research, calcium carbonate particle suspensions with a particle concentration of 0.2 mg mL<sup>−1</sup> (0.0074 vol%) were created in water through ultrasonication, utilizing polyoxyethylene alkylether (Softanol-70) as the stabilizing surfactant. When dispersing particles in an aqueous phase using a surfactant, the concentration of surfactant that was not adsorbed on the particles was affected by the micellar size. When the surfactant concentration was relatively higher (above 0.2 mg mL<sup>−1</sup>), prolonged ultrasonication enabled the particles to reach and retain their smallest size by preventing re-agglomeration. This was due to the sufficient presence of non-adsorbed surfactant, which stabilized the micelle size. Conversely, at lower surfactant concentrations (less than 0.15 mg mL<sup>−1</sup>), short ultrasonic irradiation reduced particle sizes in the liquid phase; however, extending the ultrasonication duration led to re-agglomeration of the particles. The latter phenomenon was induced by the reduction of the micellar size of the surfactant from approximately 8 nm to 2–1 nm, which was related to the reduction of the amount of non-adsorbed surfactant on the particles. Interestingly, the zeta potential of the dispersing particles remained almost unchanged at approximately −24 mV during the dispersing process. This indicated that electrostatic repulsion between particles was not a significant factor in this particle suspension, whereas the micellar size of the surfactant was an important key. This finding could significantly contribute to the effective preparation of a particle suspension.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"454 ","pages":"Article 120700"},"PeriodicalIF":4.5,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-29DOI: 10.1016/j.powtec.2025.120690
Zemin Qiu, Qinghua Xiao
This study investigates the impact of driving mode on the clogging behavior of fluid-driven particles using the LB-IB-DEM method. By simulating the clogging process, we employ a power-law distribution to characterize the blockage and unblocking probabilities of particle flow. Our findings reveal that within a Reynolds number range of 5–150, the probability of particle flow blockage increases with driving force, demonstrating a “fast is slow” effect. This phenomenon is explained through a modified random walk model, highlighting the roles of geometry, chain formation probability, and chain structure evolution probability. Notably, the probability of chain structure generation rises with driving force, underpinning the “fast is slow” effect. Additionally, under flow rate control, the unblocking probability shows weak correlation with driving force, whereas under pressure control, the unblocking probability is negatively correlated with driving force. The ratio of import and export flow changes indicates that accumulation speed is crucial in determining the relationship between dredging probability and driving force, with faster accumulation reducing the likelihood of particle arch breakage.
{"title":"Exploring the ‘fast is slow’ effect in particle suspension clogging: Liquid driving and random walk models","authors":"Zemin Qiu, Qinghua Xiao","doi":"10.1016/j.powtec.2025.120690","DOIUrl":"10.1016/j.powtec.2025.120690","url":null,"abstract":"<div><div>This study investigates the impact of driving mode on the clogging behavior of fluid-driven particles using the LB-IB-DEM method. By simulating the clogging process, we employ a power-law distribution to characterize the blockage and unblocking probabilities of particle flow. Our findings reveal that within a Reynolds number range of 5–150, the probability of particle flow blockage increases with driving force, demonstrating a “fast is slow” effect. This phenomenon is explained through a modified random walk model, highlighting the roles of geometry, chain formation probability, and chain structure evolution probability. Notably, the probability of chain structure generation rises with driving force, underpinning the “fast is slow” effect. Additionally, under flow rate control, the unblocking probability shows weak correlation with driving force, whereas under pressure control, the unblocking probability is negatively correlated with driving force. The ratio of import and export flow changes indicates that accumulation speed is crucial in determining the relationship between dredging probability and driving force, with faster accumulation reducing the likelihood of particle arch breakage.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"454 ","pages":"Article 120690"},"PeriodicalIF":4.5,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-25DOI: 10.1016/j.powtec.2025.120705
Ke Chen , Ting Yao , Rui Qi , Sérgio D.N. Lourenço
Carbonate sand, widely distributed in coastal regions, presents challenge due to its high stress-dependent and time-dependent (creep) compressibility. While soil stabilization techniques have traditionally focused on enhancing the strength of carbonate sand, the evaluation on the compressibility performance of cemented carbonate sand remains a critical aspect for most envisaged practical applications. In light of recent developments in self-healing approaches for soil stabilization, this study investigated the potential of calcium alginate/Tung oil capsules to mitigate compressibility in carbonate sand. The encapsulated Tung oil serves as a healing agent, gradually releasing within the sand matrix when subjected to void ratio changes during compaction, hardening and bonding sand grains after a 30-day drying. Long-term stepwise one-dimensional compression tests were conducted on both clean sand and sand-capsule composite with different initial relative density and particle size. The overall and stress-dependent compressibility was reduced for fine sand-capsule composite, while capsules had adverse effect on the compressibility of medium and coarse sand-capsule composite. Capsules could not reduce the creep but increase the elastic response of all sand-capsule composites. The Tung oil bonding could reduce the compressibility by preventing particle breakage of sand during loading. The stabilization mechanism of capsules in carbonate sand with different particle size was further investigated through thermal analysis, CT scan and microscopic analysis, revealing that the compressibility mitigation by capsules depended on the amount of Tung oil release from capsule, which was controlled by the pore structure of sand-capsule composite.
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