Powder Technology最新文献

{"title":"Improving inhalation delivery of biologics with extra-large particles produced by spray freeze drying","authors":"Susana Farinha ,&nbsp;Marco Galésio ,&nbsp;Joana Cristóvão ,&nbsp;Paulo Lino ,&nbsp;Miguel Ângelo Rodrigues ,&nbsp;João Pires ,&nbsp;Luís Marques","doi":"10.1016/j.powtec.2025.121020","DOIUrl":"10.1016/j.powtec.2025.121020","url":null,"abstract":"<div><div>Inhalation delivery of biologics as dry powders offers a promising alternative to liquid formulations, eliminating the need for cold storage. However, controlling particle properties for efficient lung delivery is challenging. While spray drying (SD) has been successfully used, it often requires excipients not approved for inhalation. In this study, spray freeze drying (SFD) was explored as an alternative technology. Human immunoglobulin G (hIgG) was used as a model molecule and dried in a mannitol-based formulation, approved for inhalation delivery. The effect of nozzle diameter (50–100 μm) and solids' concentration (5–10 %(<em>w</em>/w)) were investigated. Despite their large size (20–300 μm), SFD particles achieved fine particle doses over emitted doses (FPD/ED) up to 80 %, which was attributed to their low density (&lt;0.52 g/cm³). The study highlights the SFD potential to enhance the aerodynamic performance of dry powder formulations for inhalation delivery, as demonstrated in comparative tests with SD.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"459 ","pages":"Article 121020"},"PeriodicalIF":4.5,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143835382","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":"Experimental study on stability and hydration process of ultra-fine cement-based slurry","authors":"Zhang Weijie ,&nbsp;Bai Yuanlin ,&nbsp;Han Chenghao ,&nbsp;Wang Pengfei ,&nbsp;Guo Yue ,&nbsp;Wang Yixiang","doi":"10.1016/j.powtec.2025.121012","DOIUrl":"10.1016/j.powtec.2025.121012","url":null,"abstract":"<div><div>Ultra-fine cement overcomes the limitations of ordinary cement, such as large particle size that hinders injection into micro-cracks and pores, and reduces the high costs of chemical slurries. Rheological properties and water-bleeding significantly affect slurry diffusion and grouting effectiveness. This study investigates the impact of the water-cement ratio, admixtures, and hydration time on water precipitation and the rheological behavior of ultra-fine cement-based slurry. The hydration process, including water migration and transformation, was analyzed to reveal the conversion dynamics of slurry water types. The effects of the water-cement ratio and admixtures on slurry hydration behavior are also discussed. The primary findings of this research are as follows: (1) The rheological parameters, including shear stress and apparent viscosity, of ultra-fine cement-based slurry decrease as the water-cement ratio increases. At a constant water-cement ratio, the rheological behavior follows the order: Ultra-fine cement&lt;Bentonite&lt;Hydroxypropyl methylcellulose. (2) The rate of water-bleeding from the ultra-fine cement-based slurry increases with a higher water-cement ratio. The addition of bentonite slightly reduces the water-bleeding rate. Conversely, hydroxypropyl methylcellulose markedly inhibits the water-bleeding rate of the slurry. (3) This study reveals the mechanism of water migration from capillary pores to gel pores and demonstrates that bentonite slows the hydration rate, while hydroxypropyl methyl cellulose accelerates it. The findings offer valuable theoretical insights and practical guidance for optimizing the use of ultra-fine cement slurry in micro-crack sealing and permeability control applications.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"459 ","pages":"Article 121012"},"PeriodicalIF":4.5,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143807876","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":"Influence of the particle distribution on dust explosions in the 20 L sphere","authors":"Kasun Weerasekara ,&nbsp;Stefan H. Spitzer ,&nbsp;Sabine Zakel ,&nbsp;Holger Grosshans","doi":"10.1016/j.powtec.2025.120984","DOIUrl":"10.1016/j.powtec.2025.120984","url":null,"abstract":"&lt;div&gt;&lt;div&gt;It is essential to standardize the safety characteristics of dust explosions to mitigate their impact on the process industries. The 20 L sphere primarily investigates the safety characteristics, namely explosion pressure (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;ex&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;) and the rate of pressure rise (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;ex&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;), of dust explosions at the laboratory level. Ensuring uniform dust distribution inside the sphere is essential for accurate data acquisition and standardization. However, whirls created by the incoming flow through the nozzle yield particles to concentrate near the wall before ignition. This study simulated the explosion inside a 20 L sphere to investigate the impact of near-wall particle concentration on the safety characteristics. The OpenFOAM model based on the Euler-Lagrangian approach was benchmarked against experimental data of lycopodium dust explosions. A novel radial homogeneity parameter &lt;span&gt;&lt;math&gt;&lt;mi&gt;Φ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mi&gt;Φ&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; quantifies the near-wall particle concentration. The parameter &lt;span&gt;&lt;math&gt;&lt;mi&gt;Φ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; is calculated using a power law based on the radial component of particle coordinates, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;Φ&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; indicating a uniform distribution, and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;Φ&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; for all particles concentrating on the wall. Different particle distributions (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;Φ&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mo&gt;…&lt;/mo&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;) are initiated before ignition. As &lt;span&gt;&lt;math&gt;&lt;mi&gt;Φ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; decreases from 1, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;ex&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;ex&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; first decrease, but beyond a certain point, both parameters increase. At &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;Φ&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, both &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;ex&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;ex&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; reach their highest values, which are 1.75% and 10.1% higher than the uniform distribution, respectively. The lowest values arise at &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;Φ&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;7&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, with reductions of 0.25% and 5.6% compared to the uniform distribution. Thus, high near-wall concen","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"459 ","pages":"Article 120984"},"PeriodicalIF":4.5,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838408","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":"AI-assisted prediction of particle impact deformation simulated by Material Point Method","authors":"Saba Saifoori ,&nbsp;Somayeh Hosseinhashemi ,&nbsp;Mohammad Alasossi ,&nbsp;Carsten Schilde ,&nbsp;Saeid Nezamabadi ,&nbsp;Mojtaba Ghadiri","doi":"10.1016/j.powtec.2025.121018","DOIUrl":"10.1016/j.powtec.2025.121018","url":null,"abstract":"<div><div>A hybrid AI framework has been adopted to link the impact deformation of elastic-perfectly plastic particles with their material properties and impact velocity. Initially, Material Point Method (MPM) is employed to simulate the impact of an elastic-perfectly plastic particle with a rigid wall, covering an extensive range of material properties and impact velocities. The simulation results are then integrated into the AI framework to establish the relationship between the input and output parameters. Consequently, dimensionless equations are derived to predict the equivalent plastic strain and deformation extent based on the material properties and impact velocity of the particle, showing a strong agreement with the MPM results. The identified equations reveal that both the equivalent plastic strain and deformation extent depend on and can be determined from the yield strength of the material as well as the fraction of the incident kinetic energy that is spent on inducing plastic deformation. The validity of the equations is verified by comparing the MPM and predicted values of the equivalent plastic strain and deformation extent for cases with material properties and impact velocities beyond the initial dataset used for developing the equations. The equation identified by the framework for prediction of the deformation extent is further validated by impact experiments. Additionally, a correlation is suggested to estimate the coefficient of restitution based on the material properties, covering a wide range.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"459 ","pages":"Article 121018"},"PeriodicalIF":4.5,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143826012","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":"Co-combustion and pollutant formation characteristics of fine oil shale and lignite in a 75 t/h CFB boiler","authors":"Hongpeng Liu ,&nbsp;Xuexin Xiang ,&nbsp;Zhixue Wang ,&nbsp;Haiwen Sun ,&nbsp;Chunxia Jia ,&nbsp;Jianye Pu ,&nbsp;Hong Qin ,&nbsp;Qing Wang","doi":"10.1016/j.powtec.2025.121011","DOIUrl":"10.1016/j.powtec.2025.121011","url":null,"abstract":"<div><div>Oil shale gas heat carrier retorting is an effective utilization method of oil shale, oil shale fines are generated in this process which have a significant calorific value. Consequently, CFB combustion stands out as an effective methods to utilize these fine oil shale particles. This study conducted experiments blending low-calorific-value oil shale from Beipiao in a 75 t/h lignite CFB boiler. Using the CPFD method, numerical simulations were performed to investigate the combustion characteristics of these fine oil shale particles. The study explored seven different oil shale blending ratios and analyzed their impact, along with various feeding methods, on the combustion and pollutant emission characteristics of the CFB boiler. The findings revealed that increasing the blending ratio from 0 % to 35 % resulted in a decrease in the average hourly furnace temperature from 1145 K to below 1080 K. Additionally, the NO concentration rose from 188 mg/Nm³ to 289 mg/Nm³, the SO₂ concentration escalated from 2335 mg/Nm³ to 6765 mg/Nm³. The study suggests that without modifications to the boiler body, the blending ratio should not exceed 35 %. The optimal feeding method involves supplying oil shale from both sides. These results provide valuable insights into the utilization of low-calorific-value and high-ash fuels for CFB combustion.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"459 ","pages":"Article 121011"},"PeriodicalIF":4.5,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143826011","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":"Experimental study and numerical simulation of gas-solid flow characteristics in 1MWth compact-fast dual fluidized bed","authors":"Shubo Chen ,&nbsp;Fangjun Wang ,&nbsp;Shiyi Chen ,&nbsp;Wenguo Xiang ,&nbsp;Xiang Xu ,&nbsp;Xiquan Li","doi":"10.1016/j.powtec.2025.121009","DOIUrl":"10.1016/j.powtec.2025.121009","url":null,"abstract":"<div><div>This study presents the design and operational validation of a 1 MW_th compact-fast dual fluidized bed system for calcium looping biomass gasification, scaled up from a lab-scale 10 kW_th fluidized bed device. A series of cold-state gas-solid flow experiments were conducted to evaluate the hydrodynamic performance of the system. Results indicate stable pressure balance across various operating conditions, with U-type loop seals demonstrating effective pressure self-regulation. The distribution of bed materials in each reactor exhibited consistent and controllable variations in response to changes in loop seal aeration, highlighting the operational flexibility and stability of the loop seals in modulating solid circulation. The solid circulation flux was widely adjustable under different flow control strategies, ensuring compatibility with subsequent high-temperature biomass gasification tests. High-temperature gas-solid flow experiments further confirmed the system's stable operation under thermal conditions. Continuum Particle Fluid Dynamics (CPFD) simulations validated the hydrodynamic feasibility of the design. This work establishes a robust foundation for advancing biomass-to‑hydrogen production using compact-fast dual fluidized bed technology.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"459 ","pages":"Article 121009"},"PeriodicalIF":4.5,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823492","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":"The effect of surface roughness and particle size on the shear characteristics of spherical particle materials","authors":"Meng Miao,&nbsp;Fengyin Liu,&nbsp;Yu Yin,&nbsp;Yuqing Tang","doi":"10.1016/j.powtec.2025.121017","DOIUrl":"10.1016/j.powtec.2025.121017","url":null,"abstract":"<div><div>This study aims to systematically investigate the influence mechanism of particle size and surface roughness on the shear mechanical behavior of spherical particle materials. Rough glass beads with different particle sizes (2 mm, 3 mm, 4 mm) were prepared using sandblasting technique. Together with smooth glass beads, they were used as test raw materials for indoor triaxial consolidated - drained (CD) tests. Based on the quantitative characterization of particle surface roughness, the differences in the shear mechanical properties of spherical particle materials, including stress - strain curves, strength parameters, critical state characteristics, and stick - slip behavior, etc., were discussed from the aspects of the particle size effect (R), the surface roughness index (Ra), and the normalized roughness effect (Ra/R). The main research results show that: increasing the surface roughness of particles can improve various shear mechanical parameters to a certain extent. This includes effectively increasing the peak deviatoric stress, expanding the range of the strength envelope, and raising the deviatoric stress corresponding to the specimen in the critical failure state. It can significantly increase the peak friction angle <em>φ</em> by approximately 10 %–40 % and the critical state line slope (CSL slope) by about 5 %–23 %. Moreover, the increase becomes more pronounced as the particle size decreases. Meanwhile, as the normalized roughness effect (Ra/R) increases, the friction coefficient becomes larger, which greatly weakens the stick - slip behavior between particles.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"459 ","pages":"Article 121017"},"PeriodicalIF":4.5,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143815156","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":"On fluidization dynamics of Geldart D particles","authors":"Musango Lungu ,&nbsp;Jingdai Wang ,&nbsp;Yongrong Yang","doi":"10.1016/j.powtec.2025.121014","DOIUrl":"10.1016/j.powtec.2025.121014","url":null,"abstract":"<div><div>Geldart D particles have not received similar attention to other groups vis-à-vis fluidization behavior. An attempt to close this research gap is made using Coarse-Grained CFD-DEM simulations of the Small Scale Challenge Problem 1. The system's dynamics are investigated for different modeling conditions including drag correlations, particle deposition scheme, particle size distribution, statistical weight, and friction within the open-source code MFIX. The results are presented in terms of the fluidization/defluidization cycles and granular temperature. The minimum fluidization velocity (<em>U</em>_<em>mf</em>) deviation and modified dynamic Hausner Ratio (MDHR) are also employed to investigate the dynamic behavior. Geldart D literature correlations for <em>U</em>_<em>mf</em> are assessed and compared with numerical predictions and experimental measurements. Hydrodynamic forces (HDFs) rather than interparticle forces (IPFs) are the main drivers for fluidization for large particles. The selection of correct modeling options is essential for capturing accurate dynamic behavior.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"459 ","pages":"Article 121014"},"PeriodicalIF":4.5,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143815157","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":"Synergistic effect of alkali metals and fluorine on the reduction swelling properties of pellet ores: Influence of basicity","authors":"Yifan Chai ,&nbsp;Shuai Ma ,&nbsp;Yingjie Fan ,&nbsp;Peijun Liu ,&nbsp;Shengli An ,&nbsp;Suqian Gu","doi":"10.1016/j.powtec.2025.121010","DOIUrl":"10.1016/j.powtec.2025.121010","url":null,"abstract":"<div><div>Bayan Obo iron ore concentrate is a crucial raw material in steel production, but its high content of harmful elements like alkali metals and fluorine (F) affects the reduction swelling properties of pellet ores. This study aimed to clarify these effects at different basicity by simulating Bayan Obo iron ore concentrate using synthetic reagents. Comprehensive investigations were conducted using a high-temperature deformation analyzer, X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), and thermogravimetric analysis to explore the reduction swelling process, phase crystal structure, microstructure, and kinetic behavior during reduction. The results showed that under the different basicity and reduction conditions, pellet ores containing Na and F exhibited a higher reduction swelling index than those pellet ores containing K and F. The maximum total reduction swelling index for both types of pellet ores occurred at a basicity of 0.8, with values of 50.6 % and 96.5 %, respectively. Additionally, a detrimental synergistic effect between Na and F was observed, which promoted the incorporation of alkali metals into the iron oxide lattice, leading to higher lattice constants, residual stresses, and distortion. The iron whiskers in the pellet ores containing Na and F formed a coarse reticular structure, indicating a synergistic effect of Na and F in promoting the growth of iron whiskers. Thermogravimetric and kinetic analysis indicated that the synergistic interaction between Na and F decreased the initial and final reaction temperatures of the pellet ores, reduced the energy required for the reduction reaction, and accelerated the reaction process, which was a key factor in exacerbating the reduction swelling of the pellet ores.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"458 ","pages":"Article 121010"},"PeriodicalIF":4.5,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143807036","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":"Heat transfer characteristics in a liquid-solids fluidisation bed: Effect of particle diameter and fluids","authors":"Damodar Singh ,&nbsp;Ravisha Goswami ,&nbsp;Padmakar Mishra ,&nbsp;Vimal Kumar ,&nbsp;Indra Mani Mishra","doi":"10.1016/j.powtec.2025.121013","DOIUrl":"10.1016/j.powtec.2025.121013","url":null,"abstract":"<div><div>Present work deals with experimental study of heat transfer from column wall to fluidised bed for different fluids (Newtonian and non-Newtonian) and particle sizes. Fluids considered are water, sodium silicate (SS) and carboxymethyl cellulose (CMC) with different concentrations. The influence of bed-voidage (ε) and superficial liquid velocity (v_s) for different particle size, on heat transfer coefficient (<em>h</em>) is studied. For an increase in superficial liquid velocity, bed-voidage is increased and hence the heat transfer coefficient. The particle size is increased from 3.7744 mm to 6.09854 mm. For both Newtonian and non-Newtonian fluids, it is observed the value of heat transfer coefficient increased, attained a maximum value at a bed-voidage of ≈0.7 and then decreased. For 22 % SS, 2.5 % CMC and 3.5 % CMC, the fluidisation system is in aggregate regime, whereas for 14 % S.S. and water, regime changed from particulate to aggregate. Furthermore, heat transfer mechanism from wall-to-bulk of bed has been established and it is found that temperature profiles in radial direction is not flat and there is significant contribution to overall heat transfer resistance from the bulk of the bed.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"460 ","pages":"Article 121013"},"PeriodicalIF":4.5,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852314","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}