Pub Date : 2024-08-29DOI: 10.1007/s40831-024-00915-1
B. Satritama, C. Cooper, D. Fellicia, M. I. Pownceby, S. Palanisamy, A. Ang, R. Z. Mukhlis, J. Pye, A. Rahbari, G. A. Brooks, M. A. Rhamdhani
Carbon-rich sources, such as coal and carbon monoxide gas, have been extensively used in the metal industry as the reducing agent of metal oxides and as the energy source for metal production. Consequently, the extractive metal sector contributes to approximately 9.5% of global greenhouse gas emissions. Hydrogen gas offers a promising alternative to using carbon in metallurgical processes as an eco-friendly reductant and energy provider that produces water vapor as a by-product. However, molecular hydrogen has some barriers to implementation. These primarily concern the thermodynamics and kinetics of metal oxide reduction. To address these issues, researchers have explored the use of hydrogen plasma, which is generated by applying high energy to molecular hydrogen to produce atomic, ionic, and excited hydrogen species. Hydrogen plasma has thermodynamic and kinetic advantages over molecular hydrogen and carbon-based reductants since it exhibits a lower standard Gibbs free energy of reaction for H2O formation and a lower activation energy. Hydrogen plasma is also a versatile reductant as it is proven on a laboratory scale to produce metal in fewer steps, process a wide range of oxides feed and feed sizes, and be used to refine metals. There are, however, some limitations to using hydrogen plasma in extractive metallurgy. These include the cost of electricity, potential back reactions or reoxidation, and industrial scale-up challenges such as heat utilization or heat loss minimization. This study undertakes a comprehensive review of prior research on the use of hydrogen plasma for metal oxides reduction and reviewing state-of-the-art techniques for its use in extractive metallurgy applications. An overview of hydrogen plasma utilization for producing and refining several metals from primary or secondary feed materials, the many types of plasma reactors, and the commonly used parameters for each metal production process are also presented. Prospects and potential feasibility of the hydrogen plasma route are also discussed.
{"title":"Hydrogen Plasma for Low-Carbon Extractive Metallurgy: Oxides Reduction, Metals Refining, and Wastes Processing","authors":"B. Satritama, C. Cooper, D. Fellicia, M. I. Pownceby, S. Palanisamy, A. Ang, R. Z. Mukhlis, J. Pye, A. Rahbari, G. A. Brooks, M. A. Rhamdhani","doi":"10.1007/s40831-024-00915-1","DOIUrl":"https://doi.org/10.1007/s40831-024-00915-1","url":null,"abstract":"<p>Carbon-rich sources, such as coal and carbon monoxide gas, have been extensively used in the metal industry as the reducing agent of metal oxides and as the energy source for metal production. Consequently, the extractive metal sector contributes to approximately 9.5% of global greenhouse gas emissions. Hydrogen gas offers a promising alternative to using carbon in metallurgical processes as an eco-friendly reductant and energy provider that produces water vapor as a by-product. However, molecular hydrogen has some barriers to implementation. These primarily concern the thermodynamics and kinetics of metal oxide reduction. To address these issues, researchers have explored the use of hydrogen plasma, which is generated by applying high energy to molecular hydrogen to produce atomic, ionic, and excited hydrogen species. Hydrogen plasma has thermodynamic and kinetic advantages over molecular hydrogen and carbon-based reductants since it exhibits a lower standard Gibbs free energy of reaction for H<sub>2</sub>O formation and a lower activation energy. Hydrogen plasma is also a versatile reductant as it is proven on a laboratory scale to produce metal in fewer steps, process a wide range of oxides feed and feed sizes, and be used to refine metals. There are, however, some limitations to using hydrogen plasma in extractive metallurgy. These include the cost of electricity, potential back reactions or reoxidation, and industrial scale-up challenges such as heat utilization or heat loss minimization. This study undertakes a comprehensive review of prior research on the use of hydrogen plasma for metal oxides reduction and reviewing state-of-the-art techniques for its use in extractive metallurgy applications. An overview of hydrogen plasma utilization for producing and refining several metals from primary or secondary feed materials, the many types of plasma reactors, and the commonly used parameters for each metal production process are also presented. Prospects and potential feasibility of the hydrogen plasma route are also discussed.</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":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199566","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 : 2024-08-22DOI: 10.1007/s40831-024-00901-7
Wei Wang, Kunmo Zhang, Guoling Zhang, Hao Zhang
The influence of catalyst on the physical properties and CO2 reactivity of carbon anodes after baking has been investigated in this paper. Raman spectra and X-ray diffraction patterns show that there is more well-ordered structure in carbon anodes with iron and titanium additives. The metal additives promote the crystalline size of graphite and graphitization extent. The appearance of the interaction between various pitch and coke surface is revealed by the optical microscopy. Gasification induces the anodes disordering to some extent. A detailed investigation indicates that there is a close relationship between the microstructure and anode properties. Owing to the improvement of graphitization extent, the properties of biopitch anodes with metal additives are better than that of conventional coal-tar-pitch samples, which can mitigate the adverse impact of its low coking value and amorphous structure on the density of the anodes. The catalytic graphitization mechanism is proposed for the transition of amorphous carbon to graphite structure at a lower temperature. The results indicate that the biopitch anodes with iron and titanium as catalysts are promising for potential application. This study proposes a green method for designing a high coking value carbon anode with biopitch as a binder by catalytic graphitization.
Graphical Abstract
本文研究了催化剂对碳阳极烘烤后的物理性质和二氧化碳反应性的影响。拉曼光谱和 X 射线衍射图显示，添加铁和钛的碳阳极具有更有序的结构。金属添加剂促进了石墨的结晶尺寸和石墨化程度。光学显微镜显示了各种沥青与焦炭表面之间的相互作用。气化在一定程度上引起了阳极的紊乱。详细研究表明，微观结构与阳极特性之间存在密切关系。由于石墨化程度的提高，添加了金属添加剂的生物沥青阳极的性能优于传统的煤焦油沥青样品，从而减轻了其低结焦值和非晶结构对阳极密度的不利影响。提出了在较低温度下无定形碳向石墨结构转变的催化石墨化机制。结果表明，以铁和钛为催化剂的生物沥青阳极具有良好的应用前景。本研究提出了一种通过催化石墨化设计以生物沥青为粘合剂的高结焦值碳阳极的绿色方法。
{"title":"Catalytic Effect of Iron and Titanium on the Microstructure and Properties of Biopitch Anodes","authors":"Wei Wang, Kunmo Zhang, Guoling Zhang, Hao Zhang","doi":"10.1007/s40831-024-00901-7","DOIUrl":"https://doi.org/10.1007/s40831-024-00901-7","url":null,"abstract":"<p>The influence of catalyst on the physical properties and CO<sub>2</sub> reactivity of carbon anodes after baking has been investigated in this paper. Raman spectra and X-ray diffraction patterns show that there is more well-ordered structure in carbon anodes with iron and titanium additives. The metal additives promote the crystalline size of graphite and graphitization extent. The appearance of the interaction between various pitch and coke surface is revealed by the optical microscopy. Gasification induces the anodes disordering to some extent. A detailed investigation indicates that there is a close relationship between the microstructure and anode properties. Owing to the improvement of graphitization extent, the properties of biopitch anodes with metal additives are better than that of conventional coal-tar-pitch samples, which can mitigate the adverse impact of its low coking value and amorphous structure on the density of the anodes. The catalytic graphitization mechanism is proposed for the transition of amorphous carbon to graphite structure at a lower temperature. The results indicate that the biopitch anodes with iron and titanium as catalysts are promising for potential application. This study proposes a green method for designing a high coking value carbon anode with biopitch as a binder by catalytic graphitization.</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":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199568","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}
To further improve the decomposition efficiency of wolframite in sulfuric-phosphoric mixed acid, the leaching kinetics in pressurized system was studied. The effects of stirring rate, reaction temperature, sulfuric acid concentration, phosphoric acid concentration, and mineral particle size on the leaching process were investigated, and the data could be fitted by the Avrami equation with a fitting degree of 0.9824. When the stirring rate exceeds 500 r/min, the liquid phase mass transfer was relatively sufficient, and the apparent activation energy of the reaction was 41.98 kJ/mol, which indicated chemical reaction control. And the reaction characteristic parameter was 0.44, the influence index of mineral particle size was − 1.78, and the reaction order of sulfuric acid concentration and phosphoric acid concentration were 0.4 and 0.31, respectively. The kinetics equation of the pressure sulfuric-phosphoric acid decomposition wolframite was obtained. It provided a theoretical basis for the strengthening of practical decomposition of wolframite.
{"title":"Leaching Kinetics of the Pressure Decomposition of Wolframite with Sulfuric-Phosphoric Mixed Acid","authors":"Jigang He, Yiwei Luo, Tao Lu, Zhenqiang Wang, Xingyu Chen, Ailiang Chen, Xuheng Liu, Jiangtao Li, Lihua He, Fenglong Sun, Zhongwei Zhao","doi":"10.1007/s40831-024-00899-y","DOIUrl":"https://doi.org/10.1007/s40831-024-00899-y","url":null,"abstract":"<p>To further improve the decomposition efficiency of wolframite in sulfuric-phosphoric mixed acid, the leaching kinetics in pressurized system was studied. The effects of stirring rate, reaction temperature, sulfuric acid concentration, phosphoric acid concentration, and mineral particle size on the leaching process were investigated, and the data could be fitted by the Avrami equation with a fitting degree of 0.9824. When the stirring rate exceeds 500 r/min, the liquid phase mass transfer was relatively sufficient, and the apparent activation energy of the reaction was 41.98 kJ/mol, which indicated chemical reaction control. And the reaction characteristic parameter was 0.44, the influence index of mineral particle size was − 1.78, and the reaction order of sulfuric acid concentration and phosphoric acid concentration were 0.4 and 0.31, respectively. The kinetics equation of the pressure sulfuric-phosphoric acid decomposition wolframite was obtained. It provided a theoretical basis for the strengthening of practical decomposition of wolframite.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"7 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199567","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 operational stability of the blast furnace is highly dependent upon the quality of the raw materials and operating conditions. Several problems arise in blast furnace where raw materials quality is deteriorated leading to the higher fuel consumption and increased hot metal production cost. This in turn disturbs the thermal stability of the blast furnace. The present paper is related to a system for optimizing fuel consumption rate in a blast furnace. The method comprises generating a visualization of a blast furnace. Further, identifying a reference batch of the burden which produced hot metal of desired temperature. Further, the model provides coal rate predictions for the operators, and thus prevents the large variation in the thermal conditions of the blast furnace and provides high levels of operational stability. Current prediction model considers the real-time working state of BF and calculates the fuel requirement of the furnace thereby predicting the deviation in fuel rate from normal operating value and pinpoints the process and raw material parameters causing the deviation. Moreover, the HMT is achieved by the batch of the burden whose chemistry is tracked from the supply to the consumption of the raw materials.
{"title":"A Novel Method to Determine Desired PCI Rate for Ensuring Thermal Stability in a Blast Furnace","authors":"Ashish Agrawal, Pratyush Ranjan Samantaray, Saziya Ahasan, Durgesh Shukla, Kamma Ramakrishna Rao","doi":"10.1007/s40831-024-00902-6","DOIUrl":"https://doi.org/10.1007/s40831-024-00902-6","url":null,"abstract":"<p>The operational stability of the blast furnace is highly dependent upon the quality of the raw materials and operating conditions. Several problems arise in blast furnace where raw materials quality is deteriorated leading to the higher fuel consumption and increased hot metal production cost. This in turn disturbs the thermal stability of the blast furnace. The present paper is related to a system for optimizing fuel consumption rate in a blast furnace. The method comprises generating a visualization of a blast furnace. Further, identifying a reference batch of the burden which produced hot metal of desired temperature. Further, the model provides coal rate predictions for the operators, and thus prevents the large variation in the thermal conditions of the blast furnace and provides high levels of operational stability. Current prediction model considers the real-time working state of BF and calculates the fuel requirement of the furnace thereby predicting the deviation in fuel rate from normal operating value and pinpoints the process and raw material parameters causing the deviation. Moreover, the HMT is achieved by the batch of the burden whose chemistry is tracked from the supply to the consumption of the raw materials.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"15 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199569","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 : 2024-08-19DOI: 10.1007/s40831-024-00897-0
Riina Aromaa-Stubb, Marja Rinne, Mari Lundström
Catalysts with an active phase of cobalt are crucial for Fischer–Tropsch synthesis (FTS), yet the environmental impacts of the catalyst production and the recycling of the spent catalyst remain largely unknown. The goal of this study was to evaluate the impacts of both catalyst production as well as the recycling of spent catalyst as cobalt hydroxide, cobalt sulfate, or cobalt carbonate. Life cycle assessment (LCA) was used to quantify the environmental impacts of the studied processes. The life cycle inventory (LCI) was gathered based on the mass and energy balances of process simulations built on information available in the literature. The results show that compared to primary production of equivalent products, all studied recycling processes for spent catalyst decrease the environmental impacts by more than 50% in all investigated impact categories. For example, the global warming potential (GWP) of cobalt recovery from spent FTS catalyst as cobalt sulfate was 1.7 kg CO2-eq./kg CoSO4whereas the corresponding GWP for primary production was 4 kg CO2-eq./kg CoSO4. The process hotspots of recycling were found to be the production of the chemicals consumed, particularly sodium hydroxide and sulfuric acid, which together contributed between 64 and 95% of the total environmental impacts. LCAs on FTS have included the consumption of cobalt catalyst in the LCI using various approximations. The impacts calculated for the production of cobalt catalyst in this study were found to be markedly higher. The largest contributors included the production of materials for the precursor and support, as well as NOx emissions and consumption of nitric acid.
{"title":"Life Cycle Assessment of Cobalt Catalyst Production and Recycling","authors":"Riina Aromaa-Stubb, Marja Rinne, Mari Lundström","doi":"10.1007/s40831-024-00897-0","DOIUrl":"https://doi.org/10.1007/s40831-024-00897-0","url":null,"abstract":"<p>Catalysts with an active phase of cobalt are crucial for Fischer–Tropsch synthesis (FTS), yet the environmental impacts of the catalyst production and the recycling of the spent catalyst remain largely unknown. The goal of this study was to evaluate the impacts of both catalyst production as well as the recycling of spent catalyst as cobalt hydroxide, cobalt sulfate, or cobalt carbonate. Life cycle assessment (LCA) was used to quantify the environmental impacts of the studied processes. The life cycle inventory (LCI) was gathered based on the mass and energy balances of process simulations built on information available in the literature. The results show that compared to primary production of equivalent products, all studied recycling processes for spent catalyst decrease the environmental impacts by more than 50% in all investigated impact categories. For example, the global warming potential (GWP) of cobalt recovery from spent FTS catalyst as cobalt sulfate was 1.7 kg CO<sub>2</sub>-eq./kg CoSO<sub>4</sub>whereas the corresponding GWP for primary production was 4 kg CO<sub>2</sub>-eq./kg CoSO<sub>4</sub>. The process hotspots of recycling were found to be the production of the chemicals consumed, particularly sodium hydroxide and sulfuric acid, which together contributed between 64 and 95% of the total environmental impacts. LCAs on FTS have included the consumption of cobalt catalyst in the LCI using various approximations. The impacts calculated for the production of cobalt catalyst in this study were found to be markedly higher. The largest contributors included the production of materials for the precursor and support, as well as NO<sub><i>x</i></sub> emissions and consumption of nitric acid.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"38 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199572","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 : 2024-08-15DOI: 10.1007/s40831-024-00900-8
Luana Milak Furmanski, Thuani Gesser Muller, Julia Bortolotto Nuernberg, Monize Aparecida Martins, Ângela Beatriz Coelho Arnt, Marcio Roberto da Rocha, Alexandre Zaccaron, Michael Peterson
Waste utilized for material development is increasingly under scrutiny in the pursuit of sustainability. Particularly, steel mill scale, a solid waste generated in the metallurgical industry through the oxidation of steel dowels, is a focus of study. In this investigation, X-ray diffraction (XRD) analysis identified wustite, magnetite, and hematite as crystalline phases, while X-ray fluorescence analysis revealed that iron oxides comprised 97% of the weight, with approximately 67% being elemental iron. Due to this composition, mill scale served as a precursor for ferrous sulfate heptahydrate (FeSO4·7H2O) via a process involving sulfuric acid aqueous solution leaching, ethanol filtration, and a final crystallization step. A factorial experimental design was employed to optimize the production of FeSO4·7H2O, assessing the influence of each variable parameter (reagents) and their interactions. Finally, the potential of mill scale in the production of FeSO4·7H2O, process efficiency, and quality of the resulting material were evaluated. Compared to a sample of commercial FeSO4·7H2O, the obtained material exhibited higher peak intensity in XRD, increased purity (reaching 99.83%), and similar thermal behavior in both differential thermal analysis and thermogravimetry. The yield of the FeSO4·7H2O production process from mill scale exceeded 70%.
{"title":"Efficient Production of Ferrous Sulfate from Steel Mill Scale Waste","authors":"Luana Milak Furmanski, Thuani Gesser Muller, Julia Bortolotto Nuernberg, Monize Aparecida Martins, Ângela Beatriz Coelho Arnt, Marcio Roberto da Rocha, Alexandre Zaccaron, Michael Peterson","doi":"10.1007/s40831-024-00900-8","DOIUrl":"https://doi.org/10.1007/s40831-024-00900-8","url":null,"abstract":"<p>Waste utilized for material development is increasingly under scrutiny in the pursuit of sustainability. Particularly, steel mill scale, a solid waste generated in the metallurgical industry through the oxidation of steel dowels, is a focus of study. In this investigation, X-ray diffraction (XRD) analysis identified wustite, magnetite, and hematite as crystalline phases, while X-ray fluorescence analysis revealed that iron oxides comprised 97% of the weight, with approximately 67% being elemental iron. Due to this composition, mill scale served as a precursor for ferrous sulfate heptahydrate (FeSO<sub>4</sub>·7H<sub>2</sub>O) via a process involving sulfuric acid aqueous solution leaching, ethanol filtration, and a final crystallization step. A factorial experimental design was employed to optimize the production of FeSO<sub>4</sub>·7H<sub>2</sub>O, assessing the influence of each variable parameter (reagents) and their interactions. Finally, the potential of mill scale in the production of FeSO<sub>4</sub>·7H<sub>2</sub>O, process efficiency, and quality of the resulting material were evaluated. Compared to a sample of commercial FeSO<sub>4</sub>·7H<sub>2</sub>O, the obtained material exhibited higher peak intensity in XRD, increased purity (reaching 99.83%), and similar thermal behavior in both differential thermal analysis and thermogravimetry. The yield of the FeSO<sub>4</sub>·7H<sub>2</sub>O production process from mill scale exceeded 70%.</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":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199570","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}
Acid sludge, a by-product of the Cu smelting process rich in Pb, Se, Cu, Hg, and other valuable metals, is a highly recyclable smelting material. Due to its high selenium content and various phase structures that form inter-chemical and inclusion structures with associated minerals such as copper and mercury, selective separation and recovery of Pb, Cu, Se, Hg and other components are limited. To address this problem, a cascade separation process of “H2SO4 + NaClO3 oxidized coordinated leaching—HCl and Na2SO3 selective reduction of selenium—H2C2O4 reduction of copper precipitation—NaH2PO2 reduction of mercury precipitation” was used for the efficient recovery of these metals from acidic sludge. The results showed that excellent outcomes have been obtained under optimal process parameters at each stage. In the oxidation leaching stage, Pb remains in the slag, Se, Cu, and Hg are leached into the solution, and the leaching rate is above 99%. Under appropriate concentrations of hydrochloric acid, Se was selectively separated in a complexation reaction with Na2SO3. The precipitation rate for Se was almost 100%, with Se product purity reaching up to 99.4%. After that, the precipitation rate of Cu in the oxalic acid precipitation is more than 99%, and the precipitation rate of Hg in the sodium hypophosphite reduction process is more than 99%. In addition, 99.09% of total lead, 97.64% of total selenium, 98.97% of total copper and 98.08% of total mercury in the acid sludge entered their separation products. During the process, the acid sludge's metals are effectively separated without introducing difficult impurity ions.
{"title":"Gradient Separation and Recovery of Pb, Se, Cu, and Hg from Acid Sludge by a Sustainable Hydrometallurgical Process","authors":"Xuexian Jiang, Wenyun Zhu, Wei Liu, Guixiang He, Tao Wei, Yongming Yang, Zhonglin Li, Changmao Liao, Cheng Li, Weiguang Zhang, Yibing Li, Xuejiao Cao","doi":"10.1007/s40831-024-00892-5","DOIUrl":"https://doi.org/10.1007/s40831-024-00892-5","url":null,"abstract":"<p>Acid sludge, a by-product of the Cu smelting process rich in Pb, Se, Cu, Hg, and other valuable metals, is a highly recyclable smelting material. Due to its high selenium content and various phase structures that form inter-chemical and inclusion structures with associated minerals such as copper and mercury, selective separation and recovery of Pb, Cu, Se, Hg and other components are limited. To address this problem, a cascade separation process of “H<sub>2</sub>SO<sub>4</sub> + NaClO<sub>3</sub> oxidized coordinated leaching—HCl and Na<sub>2</sub>SO<sub>3</sub> selective reduction of selenium—H<sub>2</sub>C<sub>2</sub>O<sub>4</sub> reduction of copper precipitation—NaH<sub>2</sub>PO<sub>2</sub> reduction of mercury precipitation” was used for the efficient recovery of these metals from acidic sludge. The results showed that excellent outcomes have been obtained under optimal process parameters at each stage. In the oxidation leaching stage, Pb remains in the slag, Se, Cu, and Hg are leached into the solution, and the leaching rate is above 99%. Under appropriate concentrations of hydrochloric acid, Se was selectively separated in a complexation reaction with Na<sub>2</sub>SO<sub>3</sub>. The precipitation rate for Se was almost 100%, with Se product purity reaching up to 99.4%. After that, the precipitation rate of Cu in the oxalic acid precipitation is more than 99%, and the precipitation rate of Hg in the sodium hypophosphite reduction process is more than 99%. In addition, 99.09% of total lead, 97.64% of total selenium, 98.97% of total copper and 98.08% of total mercury in the acid sludge entered their separation products. During the process, the acid sludge's metals are effectively separated without introducing difficult impurity ions.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"5 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199571","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 : 2024-08-12DOI: 10.1007/s40831-024-00896-1
Yulin Li, Jintao Gao, Xi Lan, Xiang Ji, Zhancheng Guo
Bayan Obo, located in Inner Mongolia, China, is renowned for housing the world’s largest deposit of iron-niobium-rare earth polymetallic co-associated minerals. During the process of developing and exploiting this deposit, rare earth elements and other valuable minerals are incorporated into the slag phase, resulting in a significant secondary source of rare earth resources. To effectively recover the rare earth elements, supergravity technology was used to selectively separate the three distinct rare earth phases in the CaO-SiO2-La2O3 basic slag system. The process yielded three rare earth phase pure crystals, namely La2Ca3(SiO3)6, CaxLa4.67-x(SiO4)3O1-0.5x, and LaxCa2-x(SiO4)O0.5x, which were obtained under specific conditions: a gravity coefficient of G = 1000, separation time of t = 10 min, and crystallization temperature for respective each rare earth phase (1330 °C, 1350 °C, 1600 °C). Comprehensive characterization of these crystals was conducted using Raman spectroscopy, EPMA, and XRF. The results indicated that the La2O3 content in the three rare earth phases was approximately 40 wt.%, 75 wt.%, and 20 wt.%, respectively. Notably, the CaxLa4.67-x(SiO4)3O1-0.5× phase exhibited the highest La2O3 content, making it the most valuable phase for rare earth enrichment. This study supplements the knowledge of rare earth phases in CaO-SiO2-La2O3 basic slag system, providing a theoretical reference for efficient recovery of rare earth resources and sustainable utilization of RE-bearing slag.
{"title":"Separation and Characterization of Multiple Rare Earth Phases in CaO-SiO2-La2O3 Basic Slag System","authors":"Yulin Li, Jintao Gao, Xi Lan, Xiang Ji, Zhancheng Guo","doi":"10.1007/s40831-024-00896-1","DOIUrl":"https://doi.org/10.1007/s40831-024-00896-1","url":null,"abstract":"<p>Bayan Obo, located in Inner Mongolia, China, is renowned for housing the world’s largest deposit of iron-niobium-rare earth polymetallic co-associated minerals. During the process of developing and exploiting this deposit, rare earth elements and other valuable minerals are incorporated into the slag phase, resulting in a significant secondary source of rare earth resources. To effectively recover the rare earth elements, supergravity technology was used to selectively separate the three distinct rare earth phases in the CaO-SiO<sub>2</sub>-La<sub>2</sub>O<sub>3</sub> basic slag system. The process yielded three rare earth phase pure crystals, namely La<sub>2</sub>Ca<sub>3</sub>(SiO<sub>3</sub>)<sub>6</sub>, Ca<sub>x</sub>La<sub>4.67-x</sub>(SiO<sub>4</sub>)<sub>3</sub>O<sub>1-0.5x</sub>, and La<sub>x</sub>Ca<sub>2-x</sub>(SiO<sub>4</sub>)O<sub>0.5x</sub>, which were obtained under specific conditions: a gravity coefficient of <i>G</i> = 1000, separation time of <i>t</i> = 10 min, and crystallization temperature for respective each rare earth phase (1330 °C, 1350 °C, 1600 °C). Comprehensive characterization of these crystals was conducted using Raman spectroscopy, EPMA, and XRF. The results indicated that the La<sub>2</sub>O<sub>3</sub> content in the three rare earth phases was approximately 40 wt.%, 75 wt.%, and 20 wt.%, respectively. Notably, the Ca<sub>x</sub>La<sub>4.67-x</sub>(SiO<sub>4</sub>)<sub>3</sub>O<sub>1-0.5×</sub> phase exhibited the highest La<sub>2</sub>O<sub>3</sub> content, making it the most valuable phase for rare earth enrichment. This study supplements the knowledge of rare earth phases in CaO-SiO<sub>2</sub>-La<sub>2</sub>O<sub>3</sub> basic slag system, providing a theoretical reference for efficient recovery of rare earth resources and sustainable utilization of RE-bearing slag.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"91 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199573","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 : 2024-08-12DOI: 10.1007/s40831-024-00894-3
Tingting Lu, Zhengbiao Hu, Hongliang Zhao, Shuai Deng
Slurry electrolysis (SE) is a hydrometallurgical technology that offers notable advantages in the efficient extraction of metals from complex minerals while minimizing carbon emissions. This study aimed to investigate the characteristics of solid suspension within a 1:6 scaled cold water model, employing a combination of high-speed imaging and fiber probe measurements. The effects of stirring speed (N, 60–200 rpm), solid mass concentration (c, 175–357 g/L), liquid level height (H, 270–330 mm) on the clear liquid layer, axial and radial solid concentrations, and tank homogeneity were assessed. It was found that the flow was smooth at the solid–liquid interface, with the absence of significant vortexes formations at the center. On the horizontal plane, the distribution of solid concentration was observed to be uniform in the middle region, gradually increasing toward the edges. Notably, when the stirring speed reached N = 200 rpm, the tank achieved uniform suspension, which corresponds to a speed range of 33–52 rpm in the SE prototype. The relationship between stirring speed and solid concentration was analyzed, showing that the interaction between particles cannot be ignored. Furthermore, increasing the liquid level contributes to reducing fluctuation in the liquid surface, the tank exhibited the highest level of homogeneity when the liquid level height was set to H = 300 mm.
Graphical Abstract
泥浆电解（SE）是一种湿法冶金技术，在从复杂矿物中高效提取金属方面具有显著优势，同时还能最大限度地减少碳排放。本研究采用高速成像和纤维探针测量相结合的方法，旨在研究 1:6 比例冷水模型中固体悬浮物的特性。研究评估了搅拌速度（N，60-200 rpm）、固体质量浓度（c，175-357 g/L）、液面高度（H，270-330 mm）对透明液层、轴向和径向固体浓度以及水槽均匀性的影响。结果发现，固液界面处的流动平稳，中心没有明显的涡流形成。在水平面上，观察到固体浓度在中间区域分布均匀，向边缘逐渐增加。值得注意的是，当搅拌速度达到 N = 200 rpm 时，罐内的悬浮液达到均匀，这与 SE 原型中 33-52 rpm 的速度范围相对应。分析了搅拌速度与固体浓度之间的关系，结果表明颗粒之间的相互作用不容忽视。此外，提高液面高度有助于减少液面波动，当液面高度设定为 H = 300 毫米时，罐体表现出最高的均匀度。
{"title":"Study on Solid Suspension Characteristics in a Laboratory-Scale Slurry Electrolysis Stirring Tank","authors":"Tingting Lu, Zhengbiao Hu, Hongliang Zhao, Shuai Deng","doi":"10.1007/s40831-024-00894-3","DOIUrl":"https://doi.org/10.1007/s40831-024-00894-3","url":null,"abstract":"<p>Slurry electrolysis (SE) is a hydrometallurgical technology that offers notable advantages in the efficient extraction of metals from complex minerals while minimizing carbon emissions. This study aimed to investigate the characteristics of solid suspension within a 1:6 scaled cold water model, employing a combination of high-speed imaging and fiber probe measurements. The effects of stirring speed (<i>N</i>, 60–200 rpm), solid mass concentration (<i>c</i>, 175–357 g/L), liquid level height (<i>H</i>, 270–330 mm) on the clear liquid layer, axial and radial solid concentrations, and tank homogeneity were assessed. It was found that the flow was smooth at the solid–liquid interface, with the absence of significant vortexes formations at the center. On the horizontal plane, the distribution of solid concentration was observed to be uniform in the middle region, gradually increasing toward the edges. Notably, when the stirring speed reached <i>N</i> = 200 rpm, the tank achieved uniform suspension, which corresponds to a speed range of 33–52 rpm in the SE prototype. The relationship between stirring speed and solid concentration was analyzed, showing that the interaction between particles cannot be ignored. Furthermore, increasing the liquid level contributes to reducing fluctuation in the liquid surface, the tank exhibited the highest level of homogeneity when the liquid level height was set to <i>H</i> = 300 mm.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\u0000","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":"52 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199591","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 : 2024-08-12DOI: 10.1007/s40831-024-00895-2
Anthony de Schutter, Luka Ceyssens, Giuseppe Granata, Tom Van Gerven
This work studies mineral carbonation of steel slags with the aim to reduce the amount of slag that is landfilled. Besides permanently storing carbon dioxide (CO2), carbonating the slags can improve their quality for use in beneficial applications and reduces the leaching of harmful heavy metals. In order to intensify the mineral carbonation process, mechanical activation is used to improve both the carbonation kinetics and yield. The milling is performed in a planetary ball mill which allows for high-intensity grinding, resulting in a fast reduction of the particle size and quick amorphization and disturbance of the crystal structure, allowing high reaction rates to be achieved. The effects of the three main processing parameters of a planetary ball mill—bead-to-powder ratio (R), bead size (D) and milling speed (S)—are investigated. Under optimal conditions, more than 50% of the maximum CO2 uptake is achieved in only 6 min, representing a very significant improvement over regular slurry carbonation. Quantitative XRD allows to identify the reactivity of the different crystalline phases present in the slag under different milling conditions. With the help of a mass balance, the formation of an inert outer layer consisting of silica (SiO2) is confirmed. This explains both the shell diffusion mechanism controlling the carbonation reaction and the total conversion being limited to 50–60%.
{"title":"Improving the Carbonation of Steel Slags Through Concurrent Wet Milling","authors":"Anthony de Schutter, Luka Ceyssens, Giuseppe Granata, Tom Van Gerven","doi":"10.1007/s40831-024-00895-2","DOIUrl":"https://doi.org/10.1007/s40831-024-00895-2","url":null,"abstract":"<p>This work studies mineral carbonation of steel slags with the aim to reduce the amount of slag that is landfilled. Besides permanently storing carbon dioxide (CO<sub>2</sub>), carbonating the slags can improve their quality for use in beneficial applications and reduces the leaching of harmful heavy metals. In order to intensify the mineral carbonation process, mechanical activation is used to improve both the carbonation kinetics and yield. The milling is performed in a planetary ball mill which allows for high-intensity grinding, resulting in a fast reduction of the particle size and quick amorphization and disturbance of the crystal structure, allowing high reaction rates to be achieved. The effects of the three main processing parameters of a planetary ball mill—bead-to-powder ratio <span>(R)</span>, bead size <span>(D)</span> and milling speed <span>(S)</span>—are investigated. Under optimal conditions, more than 50% of the maximum CO<sub>2</sub> uptake is achieved in only 6 min, representing a very significant improvement over regular slurry carbonation. Quantitative XRD allows to identify the reactivity of the different crystalline phases present in the slag under different milling conditions. With the help of a mass balance, the formation of an inert outer layer consisting of silica (SiO<sub>2</sub>) is confirmed. This explains both the shell diffusion mechanism controlling the carbonation reaction and the total conversion being limited to 50–60%.</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":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199597","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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