Pub Date : 2024-07-25DOI: 10.1007/s40831-024-00888-1
Manuel Vollbrecht, Krishnanjan Pramanik, Lucio Colombi Ciacchi, Lutz Mädler
Metallurgical waste streams contain minor yet significant contents of valuable and scarce elements which are commonly lost due to their low concentrations. The necessity of developing efficient recycling methods of these chemically diverse material systems is constantly gaining both public and technological attention since resource demands of high-technology elements are expected to rise drastically in the future. A novel approach to recover diluted elements from slags is the concept of Engineered Artificial Minerals (EnAM) which aims at entrapping target elements in separable crystalline phases. In this study, slag synthesis through flame spray pyrolysis (FSP) and characterization experiments are combined with theoretical density functional theory (DFT) calculations to identify potential EnAM for Co recovery. Upon validating the viability of stoichiometric slag synthesis and the DFT framework, it is shown that the actual occurrence of flame-synthesized phases can be predicted considering their computed enthalpy of formation. The thus-defined compositional space, which is spanned by potentially forming slag compounds, is employed to identify promising additives for EnAM formation. Systematic analysis of the additive effect on crystallization revealed that Co crystallizes in a Fe–Mg-Co–O cubic spinel, making this phase a good EnAM candidate.
Graphical Abstract
冶金废料流中含有少量有价值的稀缺元素，但由于浓度较低，这些元素通常会流失。由于对高科技元素的资源需求预计在未来会急剧上升，因此为这些化学性质各异的材料系统开发高效回收方法的必要性不断受到公众和技术界的关注。从炉渣中回收稀释元素的新方法是工程人工矿物（EnAM）概念，其目的是将目标元素夹杂在可分离的结晶相中。在本研究中，通过火焰喷射热解（FSP）合成炉渣，并将表征实验与理论密度泛函理论（DFT）计算相结合，以确定用于钴回收的潜在 EnAM。在验证了化学计量炉渣合成和 DFT 框架的可行性后，结果表明，火焰合成相的实际出现可以通过计算其形成焓来预测。由此定义的成分空间（由可能形成的熔渣化合物跨越）可用于识别 EnAM 形成所需的添加剂。通过系统分析添加剂对结晶的影响，发现钴在Fe-Mg-Co-O立方尖晶石中结晶，使该相成为良好的EnAM候选相。
{"title":"Investigating the Compositional Space of Gas-Phase Synthesized Fayalitic Model Slags Aiming at Cobalt Recovery","authors":"Manuel Vollbrecht, Krishnanjan Pramanik, Lucio Colombi Ciacchi, Lutz Mädler","doi":"10.1007/s40831-024-00888-1","DOIUrl":"https://doi.org/10.1007/s40831-024-00888-1","url":null,"abstract":"<p>Metallurgical waste streams contain minor yet significant contents of valuable and scarce elements which are commonly lost due to their low concentrations. The necessity of developing efficient recycling methods of these chemically diverse material systems is constantly gaining both public and technological attention since resource demands of high-technology elements are expected to rise drastically in the future. A novel approach to recover diluted elements from slags is the concept of Engineered Artificial Minerals (EnAM) which aims at entrapping target elements in separable crystalline phases. In this study, slag synthesis through flame spray pyrolysis (FSP) and characterization experiments are combined with theoretical density functional theory (DFT) calculations to identify potential EnAM for Co recovery. Upon validating the viability of stoichiometric slag synthesis and the DFT framework, it is shown that the actual occurrence of flame-synthesized phases can be predicted considering their computed enthalpy of formation. The thus-defined compositional space, which is spanned by potentially forming slag compounds, is employed to identify promising additives for EnAM formation. Systematic analysis of the additive effect on crystallization revealed that Co crystallizes in a Fe–Mg-Co–O cubic spinel, making this phase a good EnAM candidate.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"95 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141784142","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 : 2024-07-24DOI: 10.1007/s40831-024-00874-7
Shiyu Li, Wencai Zhang
Phytomining emerges as an innovative technique for extracting rare earth elements (REEs) from soil by employing hyperaccumulators. REE hyperaccumulators were treated using microwave-assisted hydrothermal carbonization (MHTC) in acid-mediated systems to efficiently transfer REEs and other elements into biocrudes and produce high purity and value-added hydrochar. However, the subsequent treatment of biocrudes to recover valuable elements still presents a significant challenge. In this study, a process that combines solvent extraction and struvite precipitation was first developed to address this challenge. In the extraction step, 95.6% of REEs were extracted using 0.05 mol/L di(2-ethylhexyl)phosphoric acid (D2EHPA) with an aqueous to organic (A/O) ratio of 1:1 at pH 3.0. However, 75.1% of Al, 81.2% of Ca, 54.5% of Fe, 61.5% of Mn, and 81.3% of Zn were co-extracted into the organic phase with the REEs. To solve this issue, a subsequent scrubbing step using deionized water was applied, with the removal of over 98% of these impurities, while incurring negligible loss of REEs. After the scrubbing step, over 97% of REEs were ultimately stripped out from the organic phase as REE oxalates using 0.01 mol/L oxalic acid as the stripping agent. Furthermore, phosphorous (P) was found to be retained in the raffinate after the solvent extraction process. 94.4% of the P was recovered by forming struvite precipitate at pH 9.0 and a Mg/P molar ratio of 1.5. In general, high purity and value-added REE products and struvite precipitate were eventually achieved from biocrudes in environmentally friendly and economically viable ways.
{"title":"Process Development for Rare Earth Elements Recovery and Struvite Production from Biocrudes","authors":"Shiyu Li, Wencai Zhang","doi":"10.1007/s40831-024-00874-7","DOIUrl":"https://doi.org/10.1007/s40831-024-00874-7","url":null,"abstract":"<p>Phytomining emerges as an innovative technique for extracting rare earth elements (REEs) from soil by employing hyperaccumulators. REE hyperaccumulators were treated using microwave-assisted hydrothermal carbonization (MHTC) in acid-mediated systems to efficiently transfer REEs and other elements into biocrudes and produce high purity and value-added hydrochar. However, the subsequent treatment of biocrudes to recover valuable elements still presents a significant challenge. In this study, a process that combines solvent extraction and struvite precipitation was first developed to address this challenge. In the extraction step, 95.6% of REEs were extracted using 0.05 mol/L di(2-ethylhexyl)phosphoric acid (D2EHPA) with an aqueous to organic (A/O) ratio of 1:1 at pH 3.0. However, 75.1% of Al, 81.2% of Ca, 54.5% of Fe, 61.5% of Mn, and 81.3% of Zn were co-extracted into the organic phase with the REEs. To solve this issue, a subsequent scrubbing step using deionized water was applied, with the removal of over 98% of these impurities, while incurring negligible loss of REEs. After the scrubbing step, over 97% of REEs were ultimately stripped out from the organic phase as REE oxalates using 0.01 mol/L oxalic acid as the stripping agent. Furthermore, phosphorous (P) was found to be retained in the raffinate after the solvent extraction process. 94.4% of the P was recovered by forming struvite precipitate at pH 9.0 and a Mg/P molar ratio of 1.5. In general, high purity and value-added REE products and struvite precipitate were eventually achieved from biocrudes in environmentally friendly and economically viable ways.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"23 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141784143","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 : 2024-07-23DOI: 10.1007/s40831-024-00882-7
A. D. P. Putera, K. Avarmaa, H. T. B. M. Petrus, G. A. Brooks, M. A. Rhamdhani
Slag treatment is one of the pyrometallurgical routes to refine and remove impurities (such as boron) from silicon. Many studies have demonstrated that the rate-controlling step in the process is the mass transfer of boron (B) in the slag phase. Hence, information regarding the B diffusivity is vital. This paper discusses the diffusivity of B in the slag from secondary data collated from previous kinetics studies and compares it with semi-empirical diffusivity equations.
{"title":"On The Diffusivity of Boron in Slag During Silicon Refining","authors":"A. D. P. Putera, K. Avarmaa, H. T. B. M. Petrus, G. A. Brooks, M. A. Rhamdhani","doi":"10.1007/s40831-024-00882-7","DOIUrl":"https://doi.org/10.1007/s40831-024-00882-7","url":null,"abstract":"<p>Slag treatment is one of the pyrometallurgical routes to refine and remove impurities (such as boron) from silicon. Many studies have demonstrated that the rate-controlling step in the process is the mass transfer of boron (B) in the slag phase. Hence, information regarding the B diffusivity is vital. This paper discusses the diffusivity of B in the slag from secondary data collated from previous kinetics studies and compares it with semi-empirical diffusivity equations.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"140 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141784145","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}
Currently, there are two research focuses in aluminum electrolysis industry: process control based on individual anodic current and current modulation. These two novel technologies share the same core mechanisms: precise control of energy balance and heat balance of aluminum electrolysis cells, which is closely linked to the changes in inter-electrode processes when the anodic current changes. In this study, the correlation between inter-electrode characteristics, including characteristics of the aluminum-electrolyte interface and anode-electrolyte interface, and current density as well as anode–cathode distance during aluminum electrolysis were investigated using the scanning reference electrode method and a see-through electrolytic cell. The obtained variation patterns of inter-electrode voltage components may serve as a reference for current balance control and precise thermal balance management in the multi-anode aluminum electrolysis system. The see-through lab-scale electrolytic cell was used to statistically analyze size distribution of gas bubbles released from the bottoms of three types of anodes during aluminum electrolysis process, aiding in understanding the resistance of the gas bubble layer.
{"title":"Study on Inter-electrode Process of Aluminum Electrolysis: An Insight into Inter-electrode Phenomena Under Current Fluctuations","authors":"Youjian Yang, Yonghui Yi, Chengping Xia, Jiangyu Yu, Qianhan Zhao, Fei Wang, Xianwei Hu, Zhaowen Wang","doi":"10.1007/s40831-024-00887-2","DOIUrl":"https://doi.org/10.1007/s40831-024-00887-2","url":null,"abstract":"<p>Currently, there are two research focuses in aluminum electrolysis industry: process control based on individual anodic current and current modulation. These two novel technologies share the same core mechanisms: precise control of energy balance and heat balance of aluminum electrolysis cells, which is closely linked to the changes in inter-electrode processes when the anodic current changes. In this study, the correlation between inter-electrode characteristics, including characteristics of the aluminum-electrolyte interface and anode-electrolyte interface, and current density as well as anode–cathode distance during aluminum electrolysis were investigated using the scanning reference electrode method and a see-through electrolytic cell. The obtained variation patterns of inter-electrode voltage components may serve as a reference for current balance control and precise thermal balance management in the multi-anode aluminum electrolysis system. The see-through lab-scale electrolytic cell was used to statistically analyze size distribution of gas bubbles released from the bottoms of three types of anodes during aluminum electrolysis process, aiding in understanding the resistance of the gas bubble layer.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"17 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141784144","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 : 2024-07-22DOI: 10.1007/s40831-024-00889-0
Chun-yang Liu, Jian-ping Yang, Chuan-ming Du, Yi Jia, You-yi Wu, Xing-wei Pei, Zhan-bo Shuang, Wu-ming Yu
Large amounts of spent MgO-C refractory are generated in steel plants annually. Compared to external recycling, internal recycling of spent refractory as a slag additive shows many advantages. However, the dissolution rate of spent MgO-C refractory in steelmaking slag is lower and small MgO-C particles are difficult to charge into the converter. To achieve its adequate dissolution and effective utilization, the spent MgO-C refractory was crushed to fabricate MgO-C briquette with a certain mechanical strength, and their dissolution behavior in steelmaking slag was investigated. The results showed that the compressive strength of MgO-C briquette increased significantly when the binder was added. The mechanical strength of MgO-C briquette can meet the requirement for transport and charging. The MgO-C briquette was readily broken to small pieces after it was added into the molten slag, and its dissolution occurred dramatically in the beginning, generating large amounts of foaming slag. The MgO-C briquette could be fully dissolved in each slag, and only some tiny MgO particles remained. The dissolution of MgO-C briquette resulted in an increase in the MgO content and a decrease in the FeO content in slag. It could provide more than 5% MgO to molten slag. Binder type had a little effect on the dissolution of MgO-C briquette in the molten slag. Decreasing slag basicity and increasing FeO content in slag facilitated the dissolution of MgO-C briquette, causing a higher MgO content in slag. This study confirmed that the complete dissolution of spent MgO-C refractory could supply heat and large amounts of MgO to the molten slag. It will not only reduce the consumption of steelmaking flux but also achieve the resource utilization of metallurgical wastes.
{"title":"Enhancing the Dissolution of Spent MgO-C Refractory in Steelmaking Slag: Towards Utilization as a Steelmaking Flux","authors":"Chun-yang Liu, Jian-ping Yang, Chuan-ming Du, Yi Jia, You-yi Wu, Xing-wei Pei, Zhan-bo Shuang, Wu-ming Yu","doi":"10.1007/s40831-024-00889-0","DOIUrl":"https://doi.org/10.1007/s40831-024-00889-0","url":null,"abstract":"<p>Large amounts of spent MgO-C refractory are generated in steel plants annually. Compared to external recycling, internal recycling of spent refractory as a slag additive shows many advantages. However, the dissolution rate of spent MgO-C refractory in steelmaking slag is lower and small MgO-C particles are difficult to charge into the converter. To achieve its adequate dissolution and effective utilization, the spent MgO-C refractory was crushed to fabricate MgO-C briquette with a certain mechanical strength, and their dissolution behavior in steelmaking slag was investigated. The results showed that the compressive strength of MgO-C briquette increased significantly when the binder was added. The mechanical strength of MgO-C briquette can meet the requirement for transport and charging. The MgO-C briquette was readily broken to small pieces after it was added into the molten slag, and its dissolution occurred dramatically in the beginning, generating large amounts of foaming slag. The MgO-C briquette could be fully dissolved in each slag, and only some tiny MgO particles remained. The dissolution of MgO-C briquette resulted in an increase in the MgO content and a decrease in the FeO content in slag. It could provide more than 5% MgO to molten slag. Binder type had a little effect on the dissolution of MgO-C briquette in the molten slag. Decreasing slag basicity and increasing FeO content in slag facilitated the dissolution of MgO-C briquette, causing a higher MgO content in slag. This study confirmed that the complete dissolution of spent MgO-C refractory could supply heat and large amounts of MgO to the molten slag. It will not only reduce the consumption of steelmaking flux but also achieve the resource utilization of metallurgical wastes.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"42 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141783914","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 occurrence of gallium in gallium-enriched coal gangue and the migration of gallium during thermal treatment were systematically studied. The phase and chemical composition of gallium-enriched coal gangue were determined, and the gallium content was determined by inductively coupled plasma mass spectrometer (ICP-MS). The mineralogical characteristics of coal gangue and liberation characteristics of main mineral phases, where gallium occurs, were analyzed using mineral liberation analyzer (MLA). The migration and occurrence of gallium in coal gangue during phase evolution after heat treatment were investigated through thermogravimetric and differential scanning calorimetry (TG-DSC) and step sequential chemical extraction procedure. The results show that the main minerals in the coal gangue are kaolinite, pyrite, and illite, and the gallium content is 38.82 ppm, of which about 84% is present in kaolinite. It is indicated that gallium mainly occurs in aluminosilicate minerals in the form of isomorphism. MLA results reveal that kaolinite in coal gangue shows a good liberation degree, while pyrite and muscovite are encapsulated with another or more minerals, reflecting lower liberation characteristics. Organic matter combustion, pyrite oxidation, calcite decomposition, aluminosilicate dehydroxylation (transformation from kaolinite to metakaolin), and conversion of metakaolin into mullite sequentially occur during thermal treatment for coal gangue. As the mineral phases evolve, gallium gradually migrates from the aluminosilicate phase, predominantly kaolinite, to the oxides of iron, potassium, magnesium, and calcium, and then to aluminosilicate at 1000 ℃. Present work sheds light on the efficient utilization for coal gangue in terms of beneficiation and gallium extraction.
{"title":"Study on the Occurrence of Gallium in Gallium-Enriched Coal Gangue and Migration During Thermal Treatment","authors":"Yiyao Liu, Haijian Yang, Linquan Sun, Jinji Yuan, Keji Wan, Zhenyong Miao, Qinggui Xiao, Tao Qi","doi":"10.1007/s40831-024-00876-5","DOIUrl":"https://doi.org/10.1007/s40831-024-00876-5","url":null,"abstract":"<p>The occurrence of gallium in gallium-enriched coal gangue and the migration of gallium during thermal treatment were systematically studied. The phase and chemical composition of gallium-enriched coal gangue were determined, and the gallium content was determined by inductively coupled plasma mass spectrometer (ICP-MS). The mineralogical characteristics of coal gangue and liberation characteristics of main mineral phases, where gallium occurs, were analyzed using mineral liberation analyzer (MLA). The migration and occurrence of gallium in coal gangue during phase evolution after heat treatment were investigated through thermogravimetric and differential scanning calorimetry (TG-DSC) and step sequential chemical extraction procedure. The results show that the main minerals in the coal gangue are kaolinite, pyrite, and illite, and the gallium content is 38.82 ppm, of which about 84% is present in kaolinite. It is indicated that gallium mainly occurs in aluminosilicate minerals in the form of isomorphism. MLA results reveal that kaolinite in coal gangue shows a good liberation degree, while pyrite and muscovite are encapsulated with another or more minerals, reflecting lower liberation characteristics. Organic matter combustion, pyrite oxidation, calcite decomposition, aluminosilicate dehydroxylation (transformation from kaolinite to metakaolin), and conversion of metakaolin into mullite sequentially occur during thermal treatment for coal gangue. As the mineral phases evolve, gallium gradually migrates from the aluminosilicate phase, predominantly kaolinite, to the oxides of iron, potassium, magnesium, and calcium, and then to aluminosilicate at 1000 ℃. Present work sheds light on the efficient utilization for coal gangue in terms of beneficiation and gallium extraction.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"6 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141740243","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 : 2024-07-17DOI: 10.1007/s40831-024-00886-3
Arun Kamalasekaran, Pelle Mellin, Christopher Hulme
The vast majority of metals production is based on the use of carbon as a reductant and/or a heating fuel. This results in a large amount of carbon dioxide emissions and should be minimized to limit global warming. In this study, powders of copper–nickel alloy and iron–nickel of varying compositions were produced in a single step by reduction of mixtures of Cu2O-NiO and Fe2O3-NiO powders, respectively, using hydrogen as a reductant. Reduction was performed in a horizontal tube furnace at 700 °C for 45 min. All processing was in the solid state and alloys were produced directly from elemental metal oxides. Exhaust gases were analyzed using a gas analyzer to measure the water content to track the progress of the reduction. Reduction was declared complete when the water content in exhaust gases matched the level before hydrogen was introduced. Both copper–nickel and iron–nickel alloys were produced successfully. X-ray diffractometry confirmed the absence of oxides in the product and the presence of solid phases in agreement with the relevant binary phase diagram. Energy-dispersive X-ray spectroscopy in a scanning electron microscope showed macroscopic homogeneity at the expected composition for each powder mixture directly after reduction, with microscopic fluctuations of the order of several mass percent, within the limits of fluctuations observed following typical casting processes. These promising results warrant further investigation to apply this concept to more chemistries and to scale up the process to a pilot scale.
{"title":"Synthesis of Copper–Nickel and Iron–Nickel Alloys by Hydrogen Reduction of Mixtures of Metal Oxide Powders","authors":"Arun Kamalasekaran, Pelle Mellin, Christopher Hulme","doi":"10.1007/s40831-024-00886-3","DOIUrl":"https://doi.org/10.1007/s40831-024-00886-3","url":null,"abstract":"<p>The vast majority of metals production is based on the use of carbon as a reductant and/or a heating fuel. This results in a large amount of carbon dioxide emissions and should be minimized to limit global warming. In this study, powders of copper–nickel alloy and iron–nickel of varying compositions were produced in a single step by reduction of mixtures of Cu<sub>2</sub>O-NiO and Fe<sub>2</sub>O<sub>3</sub>-NiO powders, respectively, using hydrogen as a reductant. Reduction was performed in a horizontal tube furnace at 700 °C for 45 min. All processing was in the solid state and alloys were produced directly from elemental metal oxides. Exhaust gases were analyzed using a gas analyzer to measure the water content to track the progress of the reduction. Reduction was declared complete when the water content in exhaust gases matched the level before hydrogen was introduced. Both copper–nickel and iron–nickel alloys were produced successfully. X-ray diffractometry confirmed the absence of oxides in the product and the presence of solid phases in agreement with the relevant binary phase diagram. Energy-dispersive X-ray spectroscopy in a scanning electron microscope showed macroscopic homogeneity at the expected composition for each powder mixture directly after reduction, with microscopic fluctuations of the order of several mass percent, within the limits of fluctuations observed following typical casting processes. These promising results warrant further investigation to apply this concept to more chemistries and to scale up the process to a pilot scale.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"43 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141740244","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 : 2024-07-17DOI: 10.1007/s40831-024-00883-6
Jiahai Bai, Chengfeng Li, Qingyang Du, Cheng Dong
Self-foamed glass ceramics were fabricated using red mud and ceramic tile polishing waste as main starting materials. Effects of red mud content in ceramics, sintering temperature and soaking time on pore structure, pore size distribution, total porosity, compressive strength and thermal conductivity were elaborately investigated. Experimental results revealed that the as-prepared self-foamed glass ceramics all exhibited homogenous foam-like structure. When the red mud content rose from 15 to 25 wt% and then up to 30 wt%, mean pore size and total porosity of the samples increased markedly and then decreased sharply, while compressive strength and thermal conductivity first decreased and then increased. As sintering temperature rose from 1110 to 1140 °C and soaking time extended from 30 to 60 min, respectively, mean pore size and total porosity increased remarkably, while compressive strength and thermal conductivity decreased appreciably. The self-foamed glass ceramics from 25 wt% red mud sintered at 1130 °C for 45 min exhibited many excellent properties including mean pore size of 0.99 mm, bulk density of 0.48 g/cm3, total density of 79.6%, high compressive strength of 8.3 MPa and low thermal conductivity of 0.08 W/m K, which made the as-fabricated self-foamed glass ceramics a good candidate material for external thermal insulator in buildings.
{"title":"Fabrication and Properties of Self-foamed Glass Ceramics from Red Mud and Ceramic Tile Polishing Waste","authors":"Jiahai Bai, Chengfeng Li, Qingyang Du, Cheng Dong","doi":"10.1007/s40831-024-00883-6","DOIUrl":"https://doi.org/10.1007/s40831-024-00883-6","url":null,"abstract":"<p>Self-foamed glass ceramics were fabricated using red mud and ceramic tile polishing waste as main starting materials. Effects of red mud content in ceramics, sintering temperature and soaking time on pore structure, pore size distribution, total porosity, compressive strength and thermal conductivity were elaborately investigated. Experimental results revealed that the as-prepared self-foamed glass ceramics all exhibited homogenous foam-like structure. When the red mud content rose from 15 to 25 wt% and then up to 30 wt%, mean pore size and total porosity of the samples increased markedly and then decreased sharply, while compressive strength and thermal conductivity first decreased and then increased. As sintering temperature rose from 1110 to 1140 °C and soaking time extended from 30 to 60 min, respectively, mean pore size and total porosity increased remarkably, while compressive strength and thermal conductivity decreased appreciably. The self-foamed glass ceramics from 25 wt% red mud sintered at 1130 °C for 45 min exhibited many excellent properties including mean pore size of 0.99 mm, bulk density of 0.48 g/cm<sup>3</sup>, total density of 79.6%, high compressive strength of 8.3 MPa and low thermal conductivity of 0.08 W/m K, which made the as-fabricated self-foamed glass ceramics a good candidate material for external thermal insulator in buildings.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"27 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141740247","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 : 2024-07-17DOI: 10.1007/s40831-024-00880-9
A. Shikika, F. A. Muvundja, M. C. Mugumaoderha, M. Aâtach, St. Gaydardzhiev
Results from purification and separation of Ta and Nb from bifluoride-based leachates aiming to produce high-purity Ta and Nb oxides are reported. The leachates have been generated through ammonium bifluoride (NH4F⋅HF) fluorination (5/1 ratio to ore), followed by sulfuric acid (1 M) leaching of the fluorinated product. Under these conditions, leachate concentration in Nb was 4.2 g/L, while Ta varied between 15 and 17 g/L. Contact time, organic/aqueous (O/A) ratio, and sulfuric acid concentration of the aqueous phase were investigated on their influence on the level of Ta/Nb extraction and separation efficiencies of methyl isobuthyl ketone (MIBK), 2-octanol (OCL), and Aliquat®336 used as solvent extractants. Results show that Ta and Nb could be successfully separated from ammonium bifluoride using the three studied extractants. In the case of MIBK and OCL (100% concentration), the optimum conditions for Ta/Nb separation were found as follows: leachate acidity—3 M, contact time—15 min, and O/A ratio—1. Separation factors of Ta against Nb (SFTa/Nb) of about 280 (MIBK) and 51 (OCL) were accordingly reached. When 3% Aliquat®336 was used, the highest Ta vs. Nb separation factor (SFTa/Nb = 180) was obtained at O/A ratio of 1 employing 2-min contact time without acidity adjustment. The separation performance of the three extractants could be ranked in the following order: MIBK > Aliquat®336 > OCL. MIBK could nevertheless be substituted at industrial scale by Aliquat®336 due to its known process relevant advantages (higher flash point (132 °C) and lower solubility < 0.5%). After stripping of the loaded Aliquat®336, Ta and Nb were precipitated and precipitates calcinated. Ta and Nb oxide powders with purity around 93% were, thus, obtained and their morphology examined by SEM.
{"title":"Separation and Purification of Ta and Nb from Ammonium Bifluoride Leachates Using Methyl Isobuthyl Ketone, 2-Octanol, and Aliquat® 336","authors":"A. Shikika, F. A. Muvundja, M. C. Mugumaoderha, M. Aâtach, St. Gaydardzhiev","doi":"10.1007/s40831-024-00880-9","DOIUrl":"https://doi.org/10.1007/s40831-024-00880-9","url":null,"abstract":"<p>Results from purification and separation of Ta and Nb from bifluoride-based leachates aiming to produce high-purity Ta and Nb oxides are reported. The leachates have been generated through ammonium bifluoride (NH<sub>4</sub>F⋅HF) fluorination (5/1 ratio to ore), followed by sulfuric acid (1 M) leaching of the fluorinated product. Under these conditions, leachate concentration in Nb was 4.2 g/L, while Ta varied between 15 and 17 g/L. Contact time, organic/aqueous (O/A) ratio, and sulfuric acid concentration of the aqueous phase were investigated on their influence on the level of Ta/Nb extraction and separation efficiencies of methyl isobuthyl ketone (MIBK), 2-octanol (OCL), and Aliquat®336 used as solvent extractants. Results show that Ta and Nb could be successfully separated from ammonium bifluoride using the three studied extractants. In the case of MIBK and OCL (100% concentration), the optimum conditions for Ta/Nb separation were found as follows: leachate acidity—3 M, contact time—15 min, and O/A ratio—1. Separation factors of Ta against Nb (SF<sub>Ta/Nb</sub>) of about 280 (MIBK) and 51 (OCL) were accordingly reached. When 3% Aliquat®336 was used, the highest Ta vs. Nb separation factor (<i>SF</i><sub>Ta/Nb</sub> = 180) was obtained at O/A ratio of 1 employing 2-min contact time without acidity adjustment. The separation performance of the three extractants could be ranked in the following order: MIBK > Aliquat®336 > OCL. MIBK could nevertheless be substituted at industrial scale by Aliquat®336 due to its known process relevant advantages (higher flash point (132 °C) and lower solubility < 0.5%). After stripping of the loaded Aliquat®336, Ta and Nb were precipitated and precipitates calcinated. Ta and Nb oxide powders with purity around 93% were, thus, obtained and their morphology examined by SEM.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"14 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141740246","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 : 2024-07-17DOI: 10.1007/s40831-024-00884-5
Zulfiadi Zulhan, Muhammad A’an, Fauzan Kamal, Sonny Djatnika Sunda Djaja, Taufiq Hidayat, R. M. Nabiel Salmanhakim, Bouman Tiroi Situmorang, Nilus Rahmat
The growth of the global population has led to a substantial increase in municipal solid waste (MSW) generation. Various methods have been suggested and implemented to address this issue, including waste processing by dry fermentation using aerobic bio-drying, resulting in treated municipal solid waste (TMSW) that can serve as an energy source. The potential application of TMSW as a reducing agent in the production of ferronickel from lateritic nickel ore was investigated. Experiments were conducted in a muffle furnace by mixing lateritic nickel ore with TMSW and heating according to specific temperature patterns. Ferronickel was produced in the form of metal nuggets, with nickel content ranging from 7–12% and iron from 84–88%, with a yield of 87% for both nickel and iron. From these results, it can be concluded that TMSW can substitute coal as a reducing agent, enabling MSW utilization and enhancing the sustainability of ferronickel production.
{"title":"Municipal Solid Waste as a Potential Reducing Agent for Substituting Coal in Ferronickel Production","authors":"Zulfiadi Zulhan, Muhammad A’an, Fauzan Kamal, Sonny Djatnika Sunda Djaja, Taufiq Hidayat, R. M. Nabiel Salmanhakim, Bouman Tiroi Situmorang, Nilus Rahmat","doi":"10.1007/s40831-024-00884-5","DOIUrl":"https://doi.org/10.1007/s40831-024-00884-5","url":null,"abstract":"<p>The growth of the global population has led to a substantial increase in municipal solid waste (MSW) generation. Various methods have been suggested and implemented to address this issue, including waste processing by dry fermentation using aerobic bio-drying, resulting in treated municipal solid waste (TMSW) that can serve as an energy source. The potential application of TMSW as a reducing agent in the production of ferronickel from lateritic nickel ore was investigated. Experiments were conducted in a muffle furnace by mixing lateritic nickel ore with TMSW and heating according to specific temperature patterns. Ferronickel was produced in the form of metal nuggets, with nickel content ranging from 7–12% and iron from 84–88%, with a yield of 87% for both nickel and iron. From these results, it can be concluded that TMSW can substitute coal as a reducing agent, enabling MSW utilization and enhancing the sustainability of ferronickel production.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"74 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141740245","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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