Powder Technology最新文献

{"title":"Coupled thermo-electric discrete element model for spark plasma sintering","authors":"F. Nisar ,&nbsp;J. Rojek ,&nbsp;S. Nosewicz ,&nbsp;K. Kaszyca ,&nbsp;M. Chmielewski","doi":"10.1016/j.powtec.2025.120957","DOIUrl":"10.1016/j.powtec.2025.120957","url":null,"abstract":"<div><div>Spark Plasma Sintering (SPS) is an emerging powder consolidation technique that employs electric current to generate heat through the Joule effect while applying pressure to achieve densification efficiently. A common concern in this process is the localization of Joule heat at the contacts between particles where electrical resistance is highest. This study investigates the coupled thermo-electric phenomena in sintered material using an original discrete element model (DEM). The model employs a two-particle sintering geometry, with particles interconnected by the neck. Neck size is evaluated using volume preservation criteria, and a correction factor compensating for non-physical overlaps as well as additional grain boundary resistance is introduced. The DEM model is verified by comparing with FEM simulations. A simple three-particle geometry is used to demonstrate that the simple DEM model gives the same potential evolution, resultant currents and temperature evolution as the more complex finite element model. Thereafter, the DEM model is validated on geometry generated using real particle size distribution to ensure heterogeneous microstructure. The effect of density on the electrical potential evolution, Joule heating and resulting increase in temperature is analysed. It is shown that the Joule heat is concentrated in the smaller particles and is conducted throughout the sample, resulting in a homogeneous increase in temperature. Ultimately, the effect of densification on heating rate is analysed. This study improves the overall understanding of thermo-electric behaviour in the SPS process, providing significant insights into the microscopic phenomena.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"458 ","pages":"Article 120957"},"PeriodicalIF":4.5,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800541","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}

{"title":"Experimentally validated DEM for large deformation powder compaction: Mechanically-derived contact model and screening of non-physical contacts","authors":"William Zunker ,&nbsp;Sachith Dunatunga ,&nbsp;Subhash Thakur ,&nbsp;Pingjun Tang ,&nbsp;Ken Kamrin","doi":"10.1016/j.powtec.2025.120972","DOIUrl":"10.1016/j.powtec.2025.120972","url":null,"abstract":"<div><div>Despite widespread industrial reliance on powder compaction in manufacturing, a complete understanding of the underlying physical mechanisms that lead to pore structure, mechanical strength, and defects remains elusive, challenging ongoing efforts to optimize the process and improve product quality. The discrete element method (DEM) is a promising tool for studying powder compaction due to its algorithmic simplicity and particle-level insights, but its application is limited by the lack of accessible, physically justified contact models for large deformations. In this work, we help address this problem by extending the recently proposed mechanically-derived adhesive elastic–plastic contact model (Zunker and Kamrin, 2024, 2024) suitable for large deformation to the case of many-interacting particles. A topological penalty algorithm for the screening of non-physical contacts occurring through obstructing particles, a phenomenon unique to large deformation DEM, is also proposed. The extended version of the contact model and topological penalty algorithm are implemented into the open-source DEM software LAMMPS (<span><span>https://github.com/lammps/lammps</span><svg><path></path></svg></span>) and validated against the multi-particle finite element method (MPFEM). The contact models unique ability to reconstruct deformed particle shapes is highlighted by comparison to FEM predictions. The industrially relevant problem of pharmaceutical tableting is simulated and comparisons to experimental data for the compaction of Avicel PH102 (microcrystalline cellulose) are made. Good agreement is observed between the experiment and numerical simulation for the axial and radial stress measurements as a function of relative density. Notably, the simulation is able to predict a similar residual radial stress after release of the axially confining pressure to that of the experiment.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"459 ","pages":"Article 120972"},"PeriodicalIF":4.5,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837892","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}

{"title":"Flow properties of uranium dioxide control-shaped powders: Link with the particle morphology and size of asperities","authors":"Christophe D’Angelo,&nbsp;Anne-Charlotte Robisson,&nbsp;Christelle Duguay","doi":"10.1016/j.powtec.2025.120824","DOIUrl":"10.1016/j.powtec.2025.120824","url":null,"abstract":"<div><div>In a nuclear fuel fabrication process, knowledge of flow properties is essential. Indeed, fuel manufacturing is based on a powder metallurgy process and each of its stages requires a good flowability. In this work, we propose to establish a quantitative link between the morphology and asperities of uranium dioxide powder particles and their flow properties. To this end, model uranium dioxide powders with a controlled particle size distribution and a controlled shape have been fabricated. A method was used, based on the image analysis resulting from the 2D projection of each particle, to characterize the morphology of the powder particles. These images were obtained using a scanning electron microscope on resin-coated particles. The morphological parameters chosen to characterize the powder are elongation, circularity and solidity. Rheological properties are obtained using an FT4 powder rheometer: the powder undergoes different tests (permeability, compressibility, and shear) to quantify its flowability. We were able to confirm that the finer the particles making up the powder, the worse the powder flow, and that the more spherical the particles making up the powder, the better the powder flow. Finally, we characterize the asperities of uranium dioxide powder particles and discuss the link between flow and Bond number using our data and data from the literature.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"459 ","pages":"Article 120824"},"PeriodicalIF":4.5,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143848647","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}

{"title":"From cloudy suspensions to clear data: Particle imaging enabled by automated dilution","authors":"Daniel Biri ,&nbsp;Ashwin Kumar Rajagopalan ,&nbsp;Marco Mazzotti","doi":"10.1016/j.powtec.2025.120965","DOIUrl":"10.1016/j.powtec.2025.120965","url":null,"abstract":"<div><div>We present a novel dilution device designed for accurately and robustly diluting dense suspensions to enable real-time particle characterization using optical imaging systems. The device employs tangential flow filtration, allowing for continuous operation at high solid weight fractions typical in industrial crystallization processes. It demonstrates the ability to monitor suspensions continuously over 24 h and to quickly adapt to changing particle densities, whilst continuously enabling accurate measurements. This paper presents also a study of the impact of particle density on measurement accuracy; extensive testing confirms the reliability of the dilution device for distributions of various particle sizes and shapes. The dilution device successfully tracks the evolution of the particle size and shape distribution (PSSD) during cooling crystallization. The innovation presented here, overcomes the limitations of existing methods hindered by high particle densities, providing a significant advancement in real-time monitoring and characterization capabilities under realistic conditions. This technology holds potential for broad applications, including the validation of new crystallization theories and, thus enhanced development of efficient crystallization processes.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"458 ","pages":"Article 120965"},"PeriodicalIF":4.5,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800469","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}

{"title":"Effect of friction on the angle of repose of elongated particles","authors":"Manuel Cárdenas-Barrantes,&nbsp;Carlos Ovalle","doi":"10.1016/j.powtec.2025.120974","DOIUrl":"10.1016/j.powtec.2025.120974","url":null,"abstract":"<div><div>The angle of repose (<span><math><mrow><mi>A</mi><mi>O</mi><mi>R</mi></mrow></math></span>) is a key parameter in powder engineering, primarily influenced by the pouring process, the inter-particle constitutive laws and particle shape. Therefore, the <span><math><mrow><mi>A</mi><mi>O</mi><mi>R</mi></mrow></math></span> of a bulk material is intuitively linked to its macromechanical internal friction angle. Previous studies indicate that more irregular particle shapes, such as angular or elongated particles, increase both shear strength and <span><math><mrow><mi>A</mi><mi>O</mi><mi>R</mi></mrow></math></span>. However, in granular materials with highly irregular shapes and low interparticle friction (or frictionless conditions), this trend reverses for the shear resistance. Despite these results, studies on the <span><math><mrow><mi>A</mi><mi>O</mi><mi>R</mi></mrow></math></span> of such materials are rare and the physical mechanisms of this behavior are unclear. This study investigates the <span><math><mrow><mi>A</mi><mi>O</mi><mi>R</mi></mrow></math></span> of dry, cohesionless granular piles composed of elongated particles using 3D DEM simulations. To represent a wide range of conditions specific to various industrial processes — including pharmaceuticals, food engineering, geotechnics, and mining — we extensively vary particle characteristics, focusing on particle elongation and interparticle friction. The particles, modeled as rounded-cap cylinders, have aspect ratios (length/diameter) ranging from 1 (spheres) to 4. For high interparticle friction (<span><math><mrow><mi>μ</mi><mo>&gt;</mo><mn>0</mn><mo>.</mo><mn>2</mn></mrow></math></span>), the <span><math><mrow><mi>A</mi><mi>O</mi><mi>R</mi></mrow></math></span> increases systematically with elongation. However, at low friction, a critical aspect ratio of 1.5 emerges, beyond which the tendency changes and the <span><math><mrow><mi>A</mi><mi>O</mi><mi>R</mi></mrow></math></span> decreases. We show that this counterintuitive behavior is related to the solid fraction, which depends on particle shape, and can be traced to purely geometrical characteristics such as coordination number and statistical particle orientation. Non-intuitively, the elongation of the particles does not influence the force distributions within the piles.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"458 ","pages":"Article 120974"},"PeriodicalIF":4.5,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143777577","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}

{"title":"Optimal design of continuous integrated crystallization-filtration processes","authors":"Psalm Josiah Tan ,&nbsp;Ming-Chun Fang ,&nbsp;Bo-Zun Lai,&nbsp;Jeffrey D. Ward","doi":"10.1016/j.powtec.2025.121006","DOIUrl":"10.1016/j.powtec.2025.121006","url":null,"abstract":"<div><div>Industrial crystallization is typically followed by filtration to separate the solid particles from the mother liquid and there is often a tradeoff between crystallizer and filter design: Investing more money in a larger crystallizer can increase crystal size and lower filtration costs. Thus, process simulation and optimization are essential to identify the optimal design of such integrated process. However such analyses are rare in the literature due to challenges in estimating cake resistance from a crystal size distribution (CSD). Recently it has been proposed to address this issue by combining the Kozeny-Carman equation with the discrete element method (DEM).</div><div>In this work, this approach is applied to optimize continuous integrated crystallization-filtration processes including those where the CSD is modified by product classification or fines removal. Results show that the optimal design depends on crystallization kinetics and slurry viscosity. For systems with low nucleation rate and low slurry viscosity, the optimal design is to minimize the crystallizer cost. For systems with high nucleation rate and high viscosity, a rigorous process model is required to determine the optimal crystallizer volume and fines dissolver design.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"459 ","pages":"Article 121006"},"PeriodicalIF":4.5,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143807875","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}

{"title":"“Nanoencapsulation of astaxanthin using gum arabic and whey protein isolate as wall materials: Characterization and invitro release kinetics”","authors":"Samira Habib ,&nbsp;Sajad Mohd Wani ,&nbsp;Khansa Rasool ,&nbsp;Barjees Ashaq ,&nbsp;Nadira Anjum ,&nbsp;Shahid Ahmad Padder ,&nbsp;Syed Zameer Hussain ,&nbsp;Nageena Nazir ,&nbsp;Shabeena Majid ,&nbsp;Sehrish Mustafa","doi":"10.1016/j.powtec.2025.120982","DOIUrl":"10.1016/j.powtec.2025.120982","url":null,"abstract":"<div><div>Astaxanthin (AST) has various biological activities, such as antioxidant, antitumor, and anti-inflammatory, but poor water solubility, instability, and low bioaccessibility greatly limit the development of its industrial application. Nanoencapsulation offers an effective method to enhance AST's stability and bioavailability. This study investigated the nanoencapsulation of AST from <em>Xanthophyllomyces dendrorhous</em> using gum arabic (GA), whey protein isolate (WPI), and GA/WPI complex as wall materials. The nanoemulsions were characterized for viscosity, droplet size and zeta potential. Analyses also included nanoencapsulated powder properties, encapsulation efficiency, encapsulation yield, FTIR, thermal stability, morphology and invitro release kinetics. Parameters such as viscosity, droplet size and zeta potential showed significant differences (<em>p</em> ≤ 0.05) among various nanoemulsions. The moisture content and water activity were in the range of 3.95–6.23 % and 0.32–0.35, respectively, which is suitable for long-term storage. The best results were achieved in GA/WPI-AST, where it had the highest encapsulation efficiency (90.31 %). FTIR revealed that the AST was well encapsulated in the nanocapsules. The results of DSC showed that the encapsulated AST changed from a crystalline state to an amorphous state. Nanocapsules displayed controlled release under simulated gastrointestinal conditions, and all the data showed good correlation with Korsmeyer-Peppas model kinetics.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"458 ","pages":"Article 120982"},"PeriodicalIF":4.5,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800472","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}

{"title":"A micromechanical framework for understanding the role of fines in the monotonic and cyclic response of granular mixtures","authors":"Kangle Zuo ,&nbsp;Xiaoqiang Gu ,&nbsp;Jing Hu ,&nbsp;Jun Yang","doi":"10.1016/j.powtec.2025.121002","DOIUrl":"10.1016/j.powtec.2025.121002","url":null,"abstract":"<div><div>The discrete-element method was employed to simulate a series of monotonic and cyclic triaxial tests on host sands (i.e. clean sands) with varying particle gradations, mixed with a range of non-plastic fines. The cyclic liquefaction resistance, critical state, and micromechanical responses of both clean sands and sand-fines mixtures were investigated. The findings reveal that both fines content (FC) and the uniformity coefficient of host sand (<em>C</em>_us) significantly influence liquefaction resistance, the critical state line in <em>e</em>-log<em>p</em>’ space, and force transmission within contact network. However, the critical stress ratio is unaffected by FC and <em>C</em>_us. Microscopic analysis indicates that, under both monotonic and cyclic loadings, sand-sand contacts primarily contribute to the deviatoric stress, while fines-fines contacts, despite their high proportion, contribute negligibly. A new contact state variable, termed the soil skeleton coordination number (MCN_sk), is proposed to capture active contacts within soil skeleton and effectively characterize the critical state behavior and liquefaction resistance of granular mixtures, independent of particle size distribution. Furthermore, liquefaction resistance is well interpreted within both macroscopic and microscopic frameworks of critical state soil mechanics. The integration of macro- and micro-level results enhances understanding of the force transmission network and associated mechanical behavior in sand-fines mixtures with varying particle size distributions.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"458 ","pages":"Article 121002"},"PeriodicalIF":4.5,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143777574","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}

{"title":"Synthesis of low-cost kaolinite-based cobalt blue composite pigments by eco-friendly mechanochemical method","authors":"Kai Chen,&nbsp;Sikai Zhao,&nbsp;Jingyu Zhang,&nbsp;Mingtao Tang,&nbsp;Qiang Zhao,&nbsp;Shuling Gao,&nbsp;Yanbai Shen","doi":"10.1016/j.powtec.2025.121007","DOIUrl":"10.1016/j.powtec.2025.121007","url":null,"abstract":"<div><div>Cobalt blue (CoAl₂O₄) pigment is widely used in various fields such as coatings, glass, ceramics, and plastics due to its brilliant blue color and excellent stability. However, the high energy consumption and the pollution of conventional preparation methods of cobalt blue pigments, as well as the gradual depletion of cobalt resources, lead to high production costs and hinder its further adoption. In this study, we prepared novel kaolinite-based CoAl₂O₄ composite pigments through a mechanochemical method followed by a calcination process, significantly reducing cobalt consumption. The experimental results showed that, with the addition of sodium carbonate at 450 %, addition of kaolinite at 40 wt%, molar ratio of added Co to Al at 0.14, and calcination temperature at 1100 °C, the prepared composite pigment exhibited optimal blue color (L^⁎ = 56.62, a^⁎ = 4.50, b^⁎ = −49.92, and C^⁎ = 50.12) coupled with good chemical stability (∆E^⁎ ≤ 1.15). Further characterization analysis revealed that the enhanced color performance was mainly attributed to the uniformly dispersed CoAl₂O₄ particles with high crystallinity on the surface of kaolinite, which led to a strong reflectance of blue visible light. Therefore, this study is expected to serve as a reference for the cost-effective and eco-friendly preparation of cobalt blue composite pigments.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"458 ","pages":"Article 121007"},"PeriodicalIF":4.5,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800542","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}

{"title":"Study on spatial flow field instability in a disturbing rotary centrifugal air classifier based on simulation and experimental methods","authors":"Xinhao Li ,&nbsp;Runyu Liu ,&nbsp;Yuhan Liu ,&nbsp;Jiale Yuan ,&nbsp;Chenlong Duan ,&nbsp;Jida Wu ,&nbsp;Hong Wang ,&nbsp;Haishen Jiang ,&nbsp;Long Huang","doi":"10.1016/j.powtec.2025.120990","DOIUrl":"10.1016/j.powtec.2025.120990","url":null,"abstract":"<div><div>Efficient particle classification in air classifiers is essential for optimizing industrial processes. However, the instability of the flow field under loading conditions remains a challenge. The gas-solid phase is subject to complex drag forces in the flow field. An imbalance in these forces can result in phenomena such as vortex eccentricity, which adversely affects the separation of target particles. In this paper, a new disturbing rotary centrifugal classifier is designed. Furthermore, numerical simulations and experimental analyses are utilized to investigate how the operating parameters influence regional flow field instability in air classifiers under loading conditions. Following the experiments, the motion of the gas-solid phase cyclone under the influence of a double-vortex structure is explored. The results indicate that the flow field in the toothed blades area exhibits a double-vortex structure with inner quasi-forced vortices and outer quasi-free vortices. The curved impeller area flow field presents a double-vortex structure with outer axial circulation and inner secondary flow. The flow field stability depends on the stability of the double-vortex structure. The impact of double-vortex structure instability on the flow field is mitigated at a critical rotational speed of 950 rpm. Comprehensive signal and experimental analyses reveal that the flow field stabilizes and classification efficiency increases to 94.9 % at a disturbing frequency of 45 Hz (950 rpm), a feed rate of 0.3 kg/s, and an inclination of - 2°. The causes of flow field instability in classifiers are clarified, and alleviation strategies are proposed in this paper, offering valuable insights for large-scale equipment applications.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"458 ","pages":"Article 120990"},"PeriodicalIF":4.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143777573","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}