The global annual industrial waste production is enormous, influencing the environmental parameters affecting the whole universe. Due to rapid industrialization, cement production is increasing to meet the demand of the construction industries, harming the atmosphere and prompting scarcity of natural resources. Thus, the need for a supplementary cementitious material is essential, replacing cement either partially or completely. In the current investigation, red mud, which has some cementitious and hydraulic characteristics, is being utilized as a supplementary cementitious material and is used as a partial replacement to cement in concrete production at different percentage levels like 0% (the control concrete), 5%, 10%, 15%, 20%, and 25% with an intension to establish the optimal replacement level established on various fresh and hardened concrete characteristics. All workable mixes are subjected to physical tests (density measurement), mechanical tests (ultrasonic pulse velocity test, rebound hammer test, compressive and tensile strength test), and durability tests (acid resistance test, sulfate resistance test, and chloride resistance test). The discussions on the concrete characterization variations can be substantiated through various microstructure level tests like scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction analysis (XRD) tests. The detailed characterization tests mutually confirmed that the optimal red mud replacement level in conventional concrete is evaluated to be 15%, leading to a sustainable production evolving reasonable waste management.
Graphical Abstract
全球每年产生的工业废物数量巨大，影响着整个宇宙的环境参数。随着工业化进程的加快，水泥产量不断增加，以满足建筑业的需求，这不仅破坏了大气环境，而且导致自然资源匮乏。因此，需要一种补充胶凝材料来部分或完全替代水泥。在当前的研究中，具有一定胶凝和水力特性的赤泥被用作一种补充胶凝材料，并在混凝土生产中以不同的百分比水平部分替代水泥，如 0%（对照混凝土）、5%、10%、15%、20% 和 25%，目的是根据各种新拌和硬化混凝土的特性确定最佳替代水平。所有可施工混合料都要经过物理测试（密度测定）、机械测试（超声波脉冲速度测试、回弹锤测试、抗压和抗拉强度测试）和耐久性测试（耐酸测试、耐硫酸盐测试和耐氯化物测试）。通过各种微观结构测试，如扫描电子显微镜（SEM）、能量色散 X 射线光谱（EDX）和 X 射线衍射分析（XRD）测试，对混凝土特性变化的讨论得到了证实。详细的表征测试相互证实，传统混凝土中最佳的赤泥替代水平被评估为 15%，从而实现了可持续生产和合理的废物管理。
{"title":"Optimal Red Mud Replacement Level Evaluation in Conventional Concrete Based on Fresh and Hardened Concrete Characteristics","authors":"Soumyaranjan Panda, Monalin Pradhan, Saubhagya Kumar Panigrahi","doi":"10.1007/s40831-024-00837-y","DOIUrl":"https://doi.org/10.1007/s40831-024-00837-y","url":null,"abstract":"<p>The global annual industrial waste production is enormous, influencing the environmental parameters affecting the whole universe. Due to rapid industrialization, cement production is increasing to meet the demand of the construction industries, harming the atmosphere and prompting scarcity of natural resources. Thus, the need for a supplementary cementitious material is essential, replacing cement either partially or completely. In the current investigation, red mud, which has some cementitious and hydraulic characteristics, is being utilized as a supplementary cementitious material and is used as a partial replacement to cement in concrete production at different percentage levels like 0% (the control concrete), 5%, 10%, 15%, 20%, and 25% with an intension to establish the optimal replacement level established on various fresh and hardened concrete characteristics. All workable mixes are subjected to physical tests (density measurement), mechanical tests (ultrasonic pulse velocity test, rebound hammer test, compressive and tensile strength test), and durability tests (acid resistance test, sulfate resistance test, and chloride resistance test). The discussions on the concrete characterization variations can be substantiated through various microstructure level tests like scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction analysis (XRD) tests. The detailed characterization tests mutually confirmed that the optimal red mud replacement level in conventional concrete is evaluated to be 15%, leading to a sustainable production evolving reasonable waste management.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"32 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140929098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recovering fluoride from industrial alkaline solutions will benefit the environmental protection and improve product quality. This paper presented a novel approach to fluoride recovery by precipitating the coarse NaF from sodium aluminate solution. The equilibrium concentration of fluoride ion in the sodium aluminate solution was first presented as a function of caustic soda concentration and temperature. Coarse NaF and high NaF precipitation efficiency were obtained by the fine particle agglomeration under conditions of inhomogeneously distributed at weak agitation (IDWA) and the addition of activated seeds. Based on particle number calculated from the particle size distribution curves, the agglomeration rate was linearly dependent on the supersaturation of NaF in sodium aluminate solution. The agglomeration mechanism was described by the fresh ultrafine particles acting as a “binder” to agglomerate the fine particles (< 10 μm) into the coarse particles (> 30 μm). Therefore, 91.15% precipitation efficiency of NaF was achieved by adding the activated seeds, adopting the special schedule of decreasing temperature, and regulating the supersaturation under IDWA. Furthermore, about 65 μm NaF with more than 98% purity was received. These results provide a novel approach for recovering NaF from the sodium aluminate solution and benefit the green development of the alumina industry.
{"title":"Seeded Precipitation of the Coarse Sodium Fluoride with High Purity for Efficient Removal of Fluoride Ion from Sodium Aluminate Solutions","authors":"Jie Tang, Guihua Liu, Tiangui Qi, Qiusheng Zhou, Zhihong Peng, Xiaobin Li, Yilin Wang, Leiting Shen","doi":"10.1007/s40831-024-00833-2","DOIUrl":"https://doi.org/10.1007/s40831-024-00833-2","url":null,"abstract":"<p>Recovering fluoride from industrial alkaline solutions will benefit the environmental protection and improve product quality. This paper presented a novel approach to fluoride recovery by precipitating the coarse NaF from sodium aluminate solution. The equilibrium concentration of fluoride ion in the sodium aluminate solution was first presented as a function of caustic soda concentration and temperature. Coarse NaF and high NaF precipitation efficiency were obtained by the fine particle agglomeration under conditions of inhomogeneously distributed at weak agitation (IDWA) and the addition of activated seeds. Based on particle number calculated from the particle size distribution curves, the agglomeration rate was linearly dependent on the supersaturation of NaF in sodium aluminate solution. The agglomeration mechanism was described by the fresh ultrafine particles acting as a “binder” to agglomerate the fine particles (< 10 μm) into the coarse particles (> 30 μm). Therefore, 91.15% precipitation efficiency of NaF was achieved by adding the activated seeds, adopting the special schedule of decreasing temperature, and regulating the supersaturation under IDWA. Furthermore, about 65 μm NaF with more than 98% purity was received. These results provide a novel approach for recovering NaF from the sodium aluminate solution and benefit the green development of the alumina industry.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"16 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140929402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-06DOI: 10.1007/s40831-024-00829-y
I. Adhiwiguna, K. Vellayadevan, Y. Tekneci, M. Walz, D. Algermissen, R. Deike
This study comprehensively assesses the ecotechnological consideration and perspective of implementing a lime-based desulfurization process in the cast iron industry to replace the utilization of magnesium partially. By adopting an injection process to introduce the lime powder into molten cast iron, this research elucidated that the new alternative concept can successfully be integrated with daily operations without any disparities in cast iron quality, as proved by the production of cast iron products with vermicular graphite. A mixture of lime powder and carbon was utilized, and it was substantiated that the aim of a sulfur content lower than 0.015% can be reliably achieved. Furthermore, an ecological analysis was also conducted to justify the possible environmental advantages. The results indicated that considering the cradle-to-gate approach, the maximum amount of CO2eq connected to the lime-based desulfurization is approximately 43 g for 1 kg of desulfurized cast iron. This amount of calculated emission is still expected to be lower than the minimum calculated emission associated with the magnesium-based process, which can reach an amount of 76 g for a similar functional unit.
{"title":"Industrial Ecotechnological Assessment of Lime as a Sustainable Substitute for Desulfurization of Cast Iron","authors":"I. Adhiwiguna, K. Vellayadevan, Y. Tekneci, M. Walz, D. Algermissen, R. Deike","doi":"10.1007/s40831-024-00829-y","DOIUrl":"https://doi.org/10.1007/s40831-024-00829-y","url":null,"abstract":"<p>This study comprehensively assesses the ecotechnological consideration and perspective of implementing a lime-based desulfurization process in the cast iron industry to replace the utilization of magnesium partially. By adopting an injection process to introduce the lime powder into molten cast iron, this research elucidated that the new alternative concept can successfully be integrated with daily operations without any disparities in cast iron quality, as proved by the production of cast iron products with vermicular graphite. A mixture of lime powder and carbon was utilized, and it was substantiated that the aim of a sulfur content lower than 0.015% can be reliably achieved. Furthermore, an ecological analysis was also conducted to justify the possible environmental advantages. The results indicated that considering the cradle-to-gate approach, the maximum amount of CO<sub>2</sub>eq connected to the lime-based desulfurization is approximately 43 g for 1 kg of desulfurized cast iron. This amount of calculated emission is still expected to be lower than the minimum calculated emission associated with the magnesium-based process, which can reach an amount of 76 g for a similar functional unit.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"37 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140929301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The utilization of coal fly ash has been of great concern in recent years due to the growing awareness of waste recycling and environmental protection. Alumina recycling from coal fly ash is a good path to realize the state-of-the-art utilization of coal fly ash. The present work proposes a novel strategy for recovering alumina and producing Fe–Si alloy from coal fly ash employing Na2SO4 as the additive. The enhancing mechanism of the Na2SO4 addition on the mullite (Al6Si2O13) decomposition and alumina extraction during vacuum carbothermic reduction of coal fly ash was systematically investigated. The thermodynamic calculation results show that the theoretical decomposition temperature of mullite can be decreased from 1048 to 683 K with the assistance of Na2SO4, which means that the addition of Na2SO4 can effectively eliminate the mullite phase. Furthermore, the aggregation of Fe–Si alloy particles was enhanced efficiently in the presence of Na2SO4, which was proved to be conducive to the alumina and Fe–Si alloy separation in the subsequent magnetic separation process. As the Na2SO4 addition amounts changed from 0 to 12 wt% at 1423 K for 4 h, the average size of the Fe–Si alloys particle exhibited an enlargement from 21.39 to 39.94 μm, by which the recovery efficiency of alumina increased from 61.03 to 75.26% correspondingly.
{"title":"The Enhancing Mechanism of Na2SO4 on Mullite Decomposition and Alumina Recovery During the Vacuum Carbothermic Reduction of Coal Fly Ash","authors":"Joseph Emmanuel Nyarko-Appiah, Wenzhou Yu, Lanjiang Song, Peng Wei, Hao Chen","doi":"10.1007/s40831-024-00832-3","DOIUrl":"https://doi.org/10.1007/s40831-024-00832-3","url":null,"abstract":"<p>The utilization of coal fly ash has been of great concern in recent years due to the growing awareness of waste recycling and environmental protection. Alumina recycling from coal fly ash is a good path to realize the state-of-the-art utilization of coal fly ash. The present work proposes a novel strategy for recovering alumina and producing Fe–Si alloy from coal fly ash employing Na<sub>2</sub>SO<sub>4</sub> as the additive. The enhancing mechanism of the Na<sub>2</sub>SO<sub>4</sub> addition on the mullite (Al<sub>6</sub>Si<sub>2</sub>O<sub>13</sub>) decomposition and alumina extraction during vacuum carbothermic reduction of coal fly ash was systematically investigated. The thermodynamic calculation results show that the theoretical decomposition temperature of mullite can be decreased from 1048 to 683 K with the assistance of Na<sub>2</sub>SO<sub>4</sub>, which means that the addition of Na<sub>2</sub>SO<sub>4</sub> can effectively eliminate the mullite phase. Furthermore, the aggregation of Fe–Si alloy particles was enhanced efficiently in the presence of Na<sub>2</sub>SO<sub>4</sub>, which was proved to be conducive to the alumina and Fe–Si alloy separation in the subsequent magnetic separation process. As the Na<sub>2</sub>SO<sub>4</sub> addition amounts changed from 0 to 12 wt% at 1423 K for 4 h, the average size of the Fe–Si alloys particle exhibited an enlargement from 21.39 to 39.94 μm, by which the recovery efficiency of alumina increased from 61.03 to 75.26% correspondingly.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"4 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140929314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-02DOI: 10.1007/s40831-024-00821-6
Xiaoqing Fang, Wenqiang Sun, Chunyou Zuo, Menglin Liu
In pursuit of energy-efficient solutions for air supply systems in steel plants, this study introduces a novel hybrid air supply system, amalgamating Waste Heat Recovery (WHR) and Excess Pressure Recovery (EPR) units. The system integrates an expander in the WHR unit and a gas turbine in the EPR unit, coaxially aligning them with the blower. A 4E model is established to evaluate the system’s energy, exergy, economic, and environmental performance. Results highlight R236ea as optimal, boasting a net power output of 1072.07 kW and an exergy efficiency of 35.62%. The WHR and EPR units contribute 73.36 and 26.64%, respectively, resulting in an electricity saving of 8.38% for the blast furnace. The minimum cost per unit of net power output with R236ea is 0.0229 $/kWh, with a dynamic payback period of 1.66 years. Compared to traditional electro-driven systems, the proposed system yields a 14.23% total cost saving. R1233zd(E) facilitates the largest net emission reduction at 202.86 kt per year, operating at an evaporation temperature of 84.3 °C. This hybrid air supply system demonstrates significant practical value, offering simultaneous benefits in energy savings, cost reduction, and emission reduction, suggesting a promising avenue for future research and development in air supply systems.
{"title":"Design and 4E Analysis of a Hybrid Air Supply System for Blast Furnaces Driven by Excess Pressure and Waste Heat Recovery","authors":"Xiaoqing Fang, Wenqiang Sun, Chunyou Zuo, Menglin Liu","doi":"10.1007/s40831-024-00821-6","DOIUrl":"https://doi.org/10.1007/s40831-024-00821-6","url":null,"abstract":"<p>In pursuit of energy-efficient solutions for air supply systems in steel plants, this study introduces a novel hybrid air supply system, amalgamating Waste Heat Recovery (WHR) and Excess Pressure Recovery (EPR) units. The system integrates an expander in the WHR unit and a gas turbine in the EPR unit, coaxially aligning them with the blower. A 4E model is established to evaluate the system’s energy, exergy, economic, and environmental performance. Results highlight R236ea as optimal, boasting a net power output of 1072.07 kW and an exergy efficiency of 35.62%. The WHR and EPR units contribute 73.36 and 26.64%, respectively, resulting in an electricity saving of 8.38% for the blast furnace. The minimum cost per unit of net power output with R236ea is 0.0229 $/kWh, with a dynamic payback period of 1.66 years. Compared to traditional electro-driven systems, the proposed system yields a 14.23% total cost saving. R1233zd(E) facilitates the largest net emission reduction at 202.86 kt per year, operating at an evaporation temperature of 84.3 °C. This hybrid air supply system demonstrates significant practical value, offering simultaneous benefits in energy savings, cost reduction, and emission reduction, suggesting a promising avenue for future research and development in air supply systems.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"21 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140828026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-01DOI: 10.1007/s40831-024-00825-2
G. Dall’Osto, D. Mombelli, V. Trombetta, C. Mapelli
Jarosite and blast furnace sludge (BFS) are two of the main wastes from hydrometallurgical zinc production and iron production by blast furnace, respectively. Jarosite is a hazardous material that can, however, be reused in the steel industry after the recovering of the iron contained within it through carbothermal reduction in which BFS is exploited as a reducing agent. Yet, both wastes have a powdery nature that makes it necessary to agglomerate them for industrial use. On the other hand, despite the advantages of producing a self-reducing product, the particle size of the starting powders and the level of gelatinization of the binder could play a crucial role on the mechanical and metallurgical performance and, consequently, on the industrial applicability of the briquettes. Accordingly, two powder particle sizes (very fine sand vs. coarse silt) and three degree of corn starch binder retrogradation (10%, 30% and non-gelatinized starch) were used to produce briquettes, and their influence was studied by experimental and statistical investigation. The results showed that gelatinization plays the main role on the mechanical properties of briquettes, while particle size affects both density and reduction behavior; in particular, although all the mixtures were able to recover iron at 950 °C the most optimal mixture were obtained by using a granulometry of 63–125 µm for jarosite and less than 63 µm for BFS, while the local maximum of mechanical performance was obtained for a 30% starch retrogradation level.
{"title":"Effect of Particle Size and Starch Gelatinization on the Mechanical and Metallurgical Performance of Jarosite Plus Blast Furnace Sludge Self-Reducing Briquettes","authors":"G. Dall’Osto, D. Mombelli, V. Trombetta, C. Mapelli","doi":"10.1007/s40831-024-00825-2","DOIUrl":"https://doi.org/10.1007/s40831-024-00825-2","url":null,"abstract":"<p>Jarosite and blast furnace sludge (BFS) are two of the main wastes from hydrometallurgical zinc production and iron production by blast furnace, respectively. Jarosite is a hazardous material that can, however, be reused in the steel industry after the recovering of the iron contained within it through carbothermal reduction in which BFS is exploited as a reducing agent. Yet, both wastes have a powdery nature that makes it necessary to agglomerate them for industrial use. On the other hand, despite the advantages of producing a self-reducing product, the particle size of the starting powders and the level of gelatinization of the binder could play a crucial role on the mechanical and metallurgical performance and, consequently, on the industrial applicability of the briquettes. Accordingly, two powder particle sizes (very fine sand vs. coarse silt) and three degree of corn starch binder retrogradation (10%, 30% and non-gelatinized starch) were used to produce briquettes, and their influence was studied by experimental and statistical investigation. The results showed that gelatinization plays the main role on the mechanical properties of briquettes, while particle size affects both density and reduction behavior; in particular, although all the mixtures were able to recover iron at 950 °C the most optimal mixture were obtained by using a granulometry of 63–125 µm for jarosite and less than 63 µm for BFS, while the local maximum of mechanical performance was obtained for a 30% starch retrogradation level.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"45 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140828028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-30DOI: 10.1007/s40831-024-00830-5
B. N. Akhgar
This investigation presents a new method for preparing nano zero-valent iron (NZVI) from mechanically activated hematite. The XRD analysis indicated that even after 240 min mechanical activation (MA), the constituent phase of hematite could be detectable without any phase change. Regarding peak broadening and reduction of peak intensity, MA generally changed the microstructural properties of hematite with more intensity during the first 60 min of intensive planetary ball milling. The microstructural study performed by the Rietveld method also proved that all microstructural parameters changed in favor of the reactivity promotion of hematite. The amorphization degree and microstrain were increased to 83% and 0.16 (%), respectively, while crystallite size was reduced to 9.2 nm after 240 min MA. Therefore, MA could promote the hematite leachability where iron extraction was increased from 14% in initial hematite to 61% in 240 min mechanically activated hematite. Leaching efficiency increased even after surface area reduction and agglomeration in 240 min mechanically activated hematite. Consequently, the surface area parameter would not be the main factor in hematite reactivity promotion, as microstructural parameters changed in favor of hematite reactivity during MA. Among the microstructural parameters, the amorphization degree and crystallite size were the predominant parameters in the reactivity promotion of 60 min mechanically activated hematite and replaced with microstrain after 240 min MA. Also, NZVI was synthesized with titrating NaBH4 through chemical precipitation from the iron-bearing solutions obtained during mechanically activated hematite leaching tests. The XRD and FE-SEM analyses also revealed that NZVI was synthesized and fairly oxidized.
{"title":"Comparing the Microstructural Changes of Mechanically Activated Hematite During Nano Zero-Valent Iron Preparation","authors":"B. N. Akhgar","doi":"10.1007/s40831-024-00830-5","DOIUrl":"https://doi.org/10.1007/s40831-024-00830-5","url":null,"abstract":"<p>This investigation presents a new method for preparing nano zero-valent iron (NZVI) from mechanically activated hematite. The XRD analysis indicated that even after 240 min mechanical activation (MA), the constituent phase of hematite could be detectable without any phase change. Regarding peak broadening and reduction of peak intensity, MA generally changed the microstructural properties of hematite with more intensity during the first 60 min of intensive planetary ball milling. The microstructural study performed by the Rietveld method also proved that all microstructural parameters changed in favor of the reactivity promotion of hematite. The amorphization degree and microstrain were increased to 83% and 0.16 (%), respectively, while crystallite size was reduced to 9.2 nm after 240 min MA. Therefore, MA could promote the hematite leachability where iron extraction was increased from 14% in initial hematite to 61% in 240 min mechanically activated hematite. Leaching efficiency increased even after surface area reduction and agglomeration in 240 min mechanically activated hematite. Consequently, the surface area parameter would not be the main factor in hematite reactivity promotion, as microstructural parameters changed in favor of hematite reactivity during MA. Among the microstructural parameters, the amorphization degree and crystallite size were the predominant parameters in the reactivity promotion of 60 min mechanically activated hematite and replaced with microstrain after 240 min MA. Also, NZVI was synthesized with titrating NaBH<sub>4</sub> through chemical precipitation from the iron-bearing solutions obtained during mechanically activated hematite leaching tests. The XRD and FE-SEM analyses also revealed that NZVI was synthesized and fairly oxidized.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"15 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140828154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-26DOI: 10.1007/s40831-024-00818-1
Zhen Zhang, Jue Tang, Mansheng Chu, Quan Shi, Chuanqiang Wang
At present, there were two main problems with the cooling plate slag-hanging: One was that the research on the slag-hanging mechanism of cooling plate was not deep, and the other was that the calculation process of the slag layer thickness with cooling plate was unreasonable. Based on ANSYS ‘birth–death element,’ a slag layer iterative cycle calculation method was designed, and the change of slag layer under different boundary conditions was analyzed. The gas temperature increased from 1200 to 1600 °C, and the slag layer decreased from 56 to 8 mm. When the gas temperature was 1550 °C, the copper cooling plate would exceeded safe operating temperature (120 °C). The thermal conductivity increased from 1.2 W·m2 °C−1 to 2.2 W·m2·°C−1, and the slag layer was able to be thickened by 76–85%; however, the slag layer would became non-uniform. When the temperature of slag-hanging increased by 50 °C, the slag layer increased by about 6.9 mm-7.6 mm, and the uniformity of slag layer increased by 10%. The maximum temperature of cooling plate could be reduced by 5°C–10°C when the cooling water speed increased by 1 m·s−1. The cooling water temperature was reduced by 10 °C, and the maximum temperature of cooling plate and the measuring point temperature could be reduced about 10 °C. The above research and analysis provided a basis for the blast furnace to have a reasonable operating furnace type and a longer life.
{"title":"Slag-Hanging Capacity of Numerical Simulation and Analysis of Blast Furnace Copper Cooling Plate Based on ANSYS ‘Birth–Death Element’","authors":"Zhen Zhang, Jue Tang, Mansheng Chu, Quan Shi, Chuanqiang Wang","doi":"10.1007/s40831-024-00818-1","DOIUrl":"https://doi.org/10.1007/s40831-024-00818-1","url":null,"abstract":"<p>At present, there were two main problems with the cooling plate slag-hanging: One was that the research on the slag-hanging mechanism of cooling plate was not deep, and the other was that the calculation process of the slag layer thickness with cooling plate was unreasonable. Based on ANSYS ‘birth–death element,’ a slag layer iterative cycle calculation method was designed, and the change of slag layer under different boundary conditions was analyzed. The gas temperature increased from 1200 to 1600 °C, and the slag layer decreased from 56 to 8 mm. When the gas temperature was 1550 °C, the copper cooling plate would exceeded safe operating temperature (120 °C). The thermal conductivity increased from 1.2 W·m<sup>2</sup> °C<sup>−1</sup> to 2.2 W·m<sup>2</sup>·°C<sup>−1</sup>, and the slag layer was able to be thickened by 76–85%; however, the slag layer would became non-uniform. When the temperature of slag-hanging increased by 50 °C, the slag layer increased by about 6.9 mm-7.6 mm, and the uniformity of slag layer increased by 10%. The maximum temperature of cooling plate could be reduced by 5°C–10°C when the cooling water speed increased by 1 m·s<sup>−1</sup>. The cooling water temperature was reduced by 10 °C, and the maximum temperature of cooling plate and the measuring point temperature could be reduced about 10 °C. The above research and analysis provided a basis for the blast furnace to have a reasonable operating furnace type and a longer life.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"18 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140798320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-18DOI: 10.1007/s40831-024-00822-5
Aparna Sai Surya Sree Nedunuri, Salman Muhammad
Alkali-activated materials are one of the alternative cementitious materials, but their extensive usage is constrained by certain limitations, such as quick setting and rapid loss of workability. By addressing these limitations, this study developed alkali-activated concrete formulations, with enhanced workable times and pumpable workability, comprising of precursors based on fly ash and blast furnace slag. The precursors were activated with sodium silicate activator of molar modulus 1.5 and activator dosage (% of Na2O) of 8 and 10%. Zinc sulfate was incorporated as a retarder to prolong the workable times. The spread diameter of these concrete mixtures measured at 10th min was in the range of 650–745 mm. Several of the developed concrete mixtures could retain the spread diameters in the range of 430 – 655 mm for a duration longer than 90 min. These developed alkali-activated concrete mixtures with pumpable workability and prolonged workable times have exhibited compressive strengths in the range of M30 to M60 grade. The rheological behavior of these concrete mixtures was also assessed on their corresponding concrete equivalent mortar (CEM) mixtures. The yield stress and plastic viscosity of CEM mixtures were found to decrease with an increase in the proportion of fly ash and increase with an increase in the hydration time and retarder content. The evolution of yield stress and plastic viscosity of alkali-activated CEM mixtures were found to be in agreement with the obtained spread diameter values for concrete mixtures.
{"title":"Development of Sodium Silicate-Activated Ground Granulated Blast Furnace Slag and Fly Ash Binder-Based Concrete for Pumping Applications","authors":"Aparna Sai Surya Sree Nedunuri, Salman Muhammad","doi":"10.1007/s40831-024-00822-5","DOIUrl":"https://doi.org/10.1007/s40831-024-00822-5","url":null,"abstract":"<p>Alkali-activated materials are one of the alternative cementitious materials, but their extensive usage is constrained by certain limitations, such as quick setting and rapid loss of workability. By addressing these limitations, this study developed alkali-activated concrete formulations, with enhanced workable times and pumpable workability, comprising of precursors based on fly ash and blast furnace slag. The precursors were activated with sodium silicate activator of molar modulus 1.5 and activator dosage (% of Na<sub>2</sub>O) of 8 and 10%. Zinc sulfate was incorporated as a retarder to prolong the workable times. The spread diameter of these concrete mixtures measured at 10th min was in the range of 650–745 mm. Several of the developed concrete mixtures could retain the spread diameters in the range of 430 – 655 mm for a duration longer than 90 min. These developed alkali-activated concrete mixtures with pumpable workability and prolonged workable times have exhibited compressive strengths in the range of M30 to M60 grade. The rheological behavior of these concrete mixtures was also assessed on their corresponding concrete equivalent mortar (CEM) mixtures. The yield stress and plastic viscosity of CEM mixtures were found to decrease with an increase in the proportion of fly ash and increase with an increase in the hydration time and retarder content. The evolution of yield stress and plastic viscosity of alkali-activated CEM mixtures were found to be in agreement with the obtained spread diameter values for concrete mixtures.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"27 1 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140629720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Monosilane (SiH4) is a common precursor for the production of high-purity silicon for solar PV applications. As an alternative to carbothermic reduction of silica to produce metallurgical grade silicon with subsequent conversion to silane, an alternative route over magnesiothermic reduction of silica to Mg2Si has been explored in our earlier work. In the current work, silane gas production through hydrolysis of Mg2Si in HCl acid solution was studied. Two sources of Mg2Si were chosen: a commercial Mg2Si source and a Mg2Si source produced through magnesiothermic reduction of high-purity natural quartz. Effects of various parameters on the hydrolysis of Mg2Si, including different experimental setups, temperature of the acid solution, acid concentration, reaction time, and relative amounts of reactants were studied. The evolution of produced gases was determined by two different methods: firstly, by passing the produced gas through a KOH solution to capture Si with subsequent analysis of the Si content in the KOH solution by inductively coupled plasma mass spectrometry and secondly, on-line gas analysis by GC–MS. The silane distribution between different silane species with reaction time was evaluated and the activation energy of silane formation was calculated. The results indicated comparable silane yields obtained from the on-line GC–MS method and KOH solution analysis method, as well as for commercial Mg2Si and the Mg2Si–MgO mixture produced through magnesiothermic reduction. Furthermore, adding HCl acid to Mg2Si in water led to higher SiH4 formation yield than adding Mg2Si to acid. However, the total silane yield for the two methods was similar at approximately 32%.
{"title":"Silane Gas Production Through Hydrolysis of Magnesium Silicide by Hydrochloric Acid","authors":"Azam Rasouli, Raphael Kuhn, Samson Yuxiu Lai, Jafar Safarian, Gabriella Tranell","doi":"10.1007/s40831-024-00817-2","DOIUrl":"https://doi.org/10.1007/s40831-024-00817-2","url":null,"abstract":"<p>Monosilane (SiH<sub>4</sub>) is a common precursor for the production of high-purity silicon for solar PV applications. As an alternative to carbothermic reduction of silica to produce metallurgical grade silicon with subsequent conversion to silane, an alternative route over magnesiothermic reduction of silica to Mg<sub>2</sub>Si has been explored in our earlier work. In the current work, silane gas production through hydrolysis of Mg<sub>2</sub>Si in HCl acid solution was studied. Two sources of Mg<sub>2</sub>Si were chosen: a commercial Mg<sub>2</sub>Si source and a Mg<sub>2</sub>Si source produced through magnesiothermic reduction of high-purity natural quartz. Effects of various parameters on the hydrolysis of Mg<sub>2</sub>Si, including different experimental setups, temperature of the acid solution, acid concentration, reaction time, and relative amounts of reactants were studied. The evolution of produced gases was determined by two different methods: firstly, by passing the produced gas through a KOH solution to capture Si with subsequent analysis of the Si content in the KOH solution by inductively coupled plasma mass spectrometry and secondly, on-line gas analysis by GC–MS. The silane distribution between different silane species with reaction time was evaluated and the activation energy of silane formation was calculated. The results indicated comparable silane yields obtained from the on-line GC–MS method and KOH solution analysis method, as well as for commercial Mg<sub>2</sub>Si and the Mg<sub>2</sub>Si–MgO mixture produced through magnesiothermic reduction. Furthermore, adding HCl acid to Mg<sub>2</sub>Si in water led to higher SiH<sub>4</sub> formation yield than adding Mg<sub>2</sub>Si to acid. However, the total silane yield for the two methods was similar at approximately 32%.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"127 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140613083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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