Pub Date : 2024-08-06DOI: 10.1007/s40831-024-00869-4
Mehmet Kayra Karacahan
The leaching behavior of pyrolusite minerals was examined in hydrochloric acid solutions, including oxalic acid, to evaluate the influence of various experimental conditions. The optimum parameters for the leaching process were found in the first stage, and the process's kinetics were assessed in the second. The concentrations of oxalic acid, hydrochloric acid, and temperature were chosen as independent variables in the optimization experiments, with the central composite design used to analyze the experimental data. The optimum concentrations for oxalic acid, hydrochloric acid, and temperature were determined to be 0.75 mol/L, 1.2 mol/L, and 60 °C, respectively. The leaching rate was determined to be 97.4% for 120 min of response time in optimum situations. The kinetic assessment experiments studied the effects of solid/liquid ratio, particle size, stirring speed, and temperature on the manganese leaching rate from pyrolusite. In the studies, the leaching rate was shown to rise with increasing temperature and stirring speed, as well as with decreasing particle size and solid/liquid ratio. The kinetic analysis revealed that the leaching kinetics matched the mixed kinetic model, and a mathematical model for the leaching process was developed. This process's activation energy was determined to be 29.05 kJ/mol.
{"title":"Optimization and Kinetic Study of Manganese Leaching from Pyrolusite Ore in Hydrochloric Acid Solutions with Oxalic Acid","authors":"Mehmet Kayra Karacahan","doi":"10.1007/s40831-024-00869-4","DOIUrl":"https://doi.org/10.1007/s40831-024-00869-4","url":null,"abstract":"<p>The leaching behavior of pyrolusite minerals was examined in hydrochloric acid solutions, including oxalic acid, to evaluate the influence of various experimental conditions. The optimum parameters for the leaching process were found in the first stage, and the process's kinetics were assessed in the second. The concentrations of oxalic acid, hydrochloric acid, and temperature were chosen as independent variables in the optimization experiments, with the central composite design used to analyze the experimental data. The optimum concentrations for oxalic acid, hydrochloric acid, and temperature were determined to be 0.75 mol/L, 1.2 mol/L, and 60 °C, respectively. The leaching rate was determined to be 97.4% for 120 min of response time in optimum situations. The kinetic assessment experiments studied the effects of solid/liquid ratio, particle size, stirring speed, and temperature on the manganese leaching rate from pyrolusite. In the studies, the leaching rate was shown to rise with increasing temperature and stirring speed, as well as with decreasing particle size and solid/liquid ratio. The kinetic analysis revealed that the leaching kinetics matched the mixed kinetic model, and a mathematical model for the leaching process was developed. This process's activation energy was determined to be 29.05 kJ/mol.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"46 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141937836","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 : 2024-08-05DOI: 10.1007/s40831-024-00891-6
Humza Ashraf, B. Deniz Karahan
A novel method for the fabrication of nanoengineered, mixed transition metal oxide anode active material is proposed based on implementing liquid nitrogen treatment during the chemical precipitation process, for the first time in open literature. Such interference in the precipitation is believed to change the surface energy of the nuclei leading to differentiation in the growth process. To exemplify this hypothesis with an environmentally friendly approach, kitchen scourer pads, an existing waste, are used as a starting material instead of using a mixture of primary quality metals’ salts. Therefore, in this study, firstly, an optimization is realized to leach the scouring pad with 100% efficiency. Then, by applying a conventional chemical precipitation to this leachate at pH 5.5, Sample 1-P is produced. Herein, innovatively liquid nitrogen treatment is carried out during the chemical precipitation to produce Sample 2-P. Lastly, these precipitates (Samples 1-P, 2-P) are calcinated in the air to form mixed transition metal oxide powders: Samples 1 and 2, respectively. Structural, chemical, and morphological characterizations are carried out to examine the effect of liquid nitrogen treatment on the powders’ properties. To discuss the effect of nitrogen treatment on the electrochemical performances of the anode active materials (Sample 1 and Sample 2), galvanostatic tests are realized. The results show that Sample 2 demonstrates a higher 1st discharge capacity (1352 mAh/g) and retains 62% of its performance after 200 cycles when 50 mA/g current load is applied. Moreover, this electrode delivers around 500 mAh/g at 1 A/g current load. The remarkable cycle performance of Sample 2 is believed to be related to the superior chemical, structural, and physical properties of the electrode active material.
{"title":"Cryo-Assisted Nitrogen Treatment for the Fabrication of Nanoengineered, Mixed Transition Metal Oxide Anode from Inorganic Domestic Waste, for Lithium-Ion Batteries","authors":"Humza Ashraf, B. Deniz Karahan","doi":"10.1007/s40831-024-00891-6","DOIUrl":"https://doi.org/10.1007/s40831-024-00891-6","url":null,"abstract":"<p>A novel method for the fabrication of nanoengineered, mixed transition metal oxide anode active material is proposed based on implementing liquid nitrogen treatment during the chemical precipitation process, for the first time in open literature. Such interference in the precipitation is believed to change the surface energy of the nuclei leading to differentiation in the growth process. To exemplify this hypothesis with an environmentally friendly approach, kitchen scourer pads, an existing waste, are used as a starting material instead of using a mixture of primary quality metals’ salts. Therefore, in this study, firstly, an optimization is realized to leach the scouring pad with 100% efficiency. Then, by applying a conventional chemical precipitation to this leachate at pH 5.5, Sample 1-P is produced. Herein, innovatively liquid nitrogen treatment is carried out during the chemical precipitation to produce Sample 2-P. Lastly, these precipitates (Samples 1-P, 2-P) are calcinated in the air to form mixed transition metal oxide powders: Samples 1 and 2, respectively. Structural, chemical, and morphological characterizations are carried out to examine the effect of liquid nitrogen treatment on the powders’ properties. To discuss the effect of nitrogen treatment on the electrochemical performances of the anode active materials (Sample 1 and Sample 2), galvanostatic tests are realized. The results show that Sample 2 demonstrates a higher 1st discharge capacity (1352 mAh/g) and retains 62% of its performance after 200 cycles when 50 mA/g current load is applied. Moreover, this electrode delivers around 500 mAh/g at 1 A/g current load. The remarkable cycle performance of Sample 2 is believed to be related to the superior chemical, structural, and physical properties of the electrode active material.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"58 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141937831","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 : 2024-08-05DOI: 10.1007/s40831-024-00878-3
Matthew S. Humbert, Geoffrey A. Brooks, Alan R. Duffy, Chad Hargrave, M. Akbar Rhamdhani
The transition to green steel production is pivotal for reducing global carbon emissions. This study presents a comprehensive techno-economic analysis of various green steel production methods, including hydrogen reduction and three different electrolysis techniques: aqueous hydroxide electrolysis (AHE), molten salt electrolysis, and molten oxide electrolysis (MOE). By comparing process flow diagrams, capital and operational expenditures, specific energy consumption, and production footprint, this work provides a high-level assessment of the economic viability of these processes as they mature. The analysis reveals that MOE, despite its ongoing development, offers a promising route for iron production given its ability to process a wide range of ore qualities and the potential to sell electrolyte as a cement product. However, the best balance between deployment ready technology and economic benefit is AHE. Operational challenges are also discussed, such as electrolyte loss and slag handling. We suggest that the sale of by-products like oxygen may not significantly impact the economics due to market saturation. The findings underscore the importance of continued research and development in process optimization to realize the full potential of green steel technologies. All the calculations have been released as supplementary electronic material (MS Excel workbook). The format has been inspired by the techno-economic assessment template (TECHTEST) distributed by the US Dept. of Energy.
{"title":"Economics of Electrowinning Iron from Ore for Green Steel Production","authors":"Matthew S. Humbert, Geoffrey A. Brooks, Alan R. Duffy, Chad Hargrave, M. Akbar Rhamdhani","doi":"10.1007/s40831-024-00878-3","DOIUrl":"https://doi.org/10.1007/s40831-024-00878-3","url":null,"abstract":"<p>The transition to green steel production is pivotal for reducing global carbon emissions. This study presents a comprehensive techno-economic analysis of various green steel production methods, including hydrogen reduction and three different electrolysis techniques: aqueous hydroxide electrolysis (AHE), molten salt electrolysis, and molten oxide electrolysis (MOE). By comparing process flow diagrams, capital and operational expenditures, specific energy consumption, and production footprint, this work provides a high-level assessment of the economic viability of these processes as they mature. The analysis reveals that MOE, despite its ongoing development, offers a promising route for iron production given its ability to process a wide range of ore qualities and the potential to sell electrolyte as a cement product. However, the best balance between deployment ready technology and economic benefit is AHE. Operational challenges are also discussed, such as electrolyte loss and slag handling. We suggest that the sale of by-products like oxygen may not significantly impact the economics due to market saturation. The findings underscore the importance of continued research and development in process optimization to realize the full potential of green steel technologies. All the calculations have been released as supplementary electronic material (MS Excel workbook). The format has been inspired by the techno-economic assessment template (TECHTEST) distributed by the US Dept. of Energy.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"97 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141937829","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 : 2024-08-02DOI: 10.1007/s40831-024-00862-x
Allan Runstedtler, Haining Gao
A process for thermal decomposition of methane to hydrogen and solid carbon is presented and examined. It utilizes the high-temperature heat from the slag by-product of blast furnace ironmaking to drive a thermal decomposition reaction, making it a waste-heat-to-hydrogen technology. This is accomplished via dry granulation of molten slag that feeds a fluidized bed reactor to effect methane–slag contact. First, the proposed process and the heat and mass balances are presented. It is found that it could produce an amount of hydrogen that is equivalent to about 20% of the reductant, depending on the iron-to-slag ratio. Then, a techno-economic analysis investigates the capital and operating costs of the process, compares the hydrogen production cost to that of other processes, and examines cost sensitivity to the prices of process inputs and outputs. This analysis suggests that the process would be suitable for on-site hydrogen production and use within a plant. In addition, using the hot slag to drive the methane decomposition would reduce hydrogen production cost by 15% compared to combusting a portion of the natural gas itself. Finally, a computational fluid dynamics (CFD) modeling study of the fluidized bed reactor examines the thermal decomposition of methane and its dependence on reaction kinetics as well as reactor design and operation. The bed operated in the bubbling regime at an average temperature between 1020 and 1060 °C and resulted in as high as 82% conversion of the methane to hydrogen, with additional optimization still possible.
{"title":"Hydrogen Production from Natural Gas Using Hot Blast Furnace Slag: Techno-economic Analysis and CFD Modeling","authors":"Allan Runstedtler, Haining Gao","doi":"10.1007/s40831-024-00862-x","DOIUrl":"https://doi.org/10.1007/s40831-024-00862-x","url":null,"abstract":"<p>A process for thermal decomposition of methane to hydrogen and solid carbon is presented and examined. It utilizes the high-temperature heat from the slag by-product of blast furnace ironmaking to drive a thermal decomposition reaction, making it a waste-heat-to-hydrogen technology. This is accomplished via dry granulation of molten slag that feeds a fluidized bed reactor to effect methane–slag contact. First, the proposed process and the heat and mass balances are presented. It is found that it could produce an amount of hydrogen that is equivalent to about 20% of the reductant, depending on the iron-to-slag ratio. Then, a techno-economic analysis investigates the capital and operating costs of the process, compares the hydrogen production cost to that of other processes, and examines cost sensitivity to the prices of process inputs and outputs. This analysis suggests that the process would be suitable for on-site hydrogen production and use within a plant. In addition, using the hot slag to drive the methane decomposition would reduce hydrogen production cost by 15% compared to combusting a portion of the natural gas itself. Finally, a computational fluid dynamics (CFD) modeling study of the fluidized bed reactor examines the thermal decomposition of methane and its dependence on reaction kinetics as well as reactor design and operation. The bed operated in the bubbling regime at an average temperature between 1020 and 1060 °C and resulted in as high as 82% conversion of the methane to hydrogen, with additional optimization still possible.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"190 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141884909","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 increase in demand for lithium-ion batteries is due to their usage in many electronic gadgets and electric vehicles. Recycling spent lithium-ion batteries plays an essential role in reducing environmental pollution and material and economic scarcity. In this paper, we employed an efficient and environmentally friendly bio-carbon based carbothermal reduction followed by a water leaching process to recover lithium and cobalt from LiCoO2(LCO)-based lithium-ion batteries. Here, the carbonized flamboyant pods (CFP) are used as a reducing agent for the carbothermal reduction process. During the carbothermal reduction process, the bio-carbon converts LiCoO2 into Co3O4 and Li2CO3. Afterwards, lithium is leached out by deionized water with a leaching efficiency of 98%, leaving Co in the residue as Co3O4. This residue is further undergoing a smelting process to recover 98.5% of Co as Co3O4. This carbothermal green recovery process is energy conserving, environmentally friendly and will bring perspective for sustainable recycling of LIBs with a minimized secondary waste.
{"title":"Bio-Carbon Assisted Carbothermal Reduction Process for the Recovery of Lithium and Cobalt from the Spent Lithium-Ion Batteries","authors":"Akhila Vasamsetti, Arrthi Ravitchandiran, Saradh Prasad Rajendra, Mohamad S. AlSalhi, Rajamohan Rajaram, Subramania Angaiah","doi":"10.1007/s40831-024-00890-7","DOIUrl":"https://doi.org/10.1007/s40831-024-00890-7","url":null,"abstract":"<p>The increase in demand for lithium-ion batteries is due to their usage in many electronic gadgets and electric vehicles. Recycling spent lithium-ion batteries plays an essential role in reducing environmental pollution and material and economic scarcity. In this paper, we employed an efficient and environmentally friendly bio-carbon based carbothermal reduction followed by a water leaching process to recover lithium and cobalt from LiCoO<sub>2</sub>(LCO)-based lithium-ion batteries. Here, the carbonized flamboyant pods (CFP) are used as a reducing agent for the carbothermal reduction process. During the carbothermal reduction process, the bio-carbon converts LiCoO<sub>2</sub> into Co<sub>3</sub>O<sub>4</sub> and Li<sub>2</sub>CO<sub>3</sub>. Afterwards, lithium is leached out by deionized water with a leaching efficiency of 98%, leaving Co in the residue as Co<sub>3</sub>O<sub>4</sub>. This residue is further undergoing a smelting process to recover 98.5% of Co as Co<sub>3</sub>O<sub>4</sub>. This carbothermal green recovery process is energy conserving, environmentally friendly and will bring perspective for sustainable recycling of LIBs with a minimized secondary waste.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"166 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141784141","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 : 2024-07-25DOI: 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}
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