Most view articles
2026, 55(2):27-38.
DOI: 10.19612/j.cnki.cn11-5066/tf.2026.02.004
Abstract:
Beryllium resources in China are primarily occur in association with other minerals， exhibiting poor mineralogical characteristics and low utilization rates. China is rich in beryllium resources， but the resources primarily occur in association with other minerals with poor low grades， resulting in low utilization rates. The overall level of development and utilization remains low. As the market demand for beryllium continues to rise， the country is facing a shortage of beryllium supply. With growing scarcity of beryllium resources and rising prices， China faces an impending beryllium supply shortage of beryllium in the future. The main beryllium ore resources include beryl， phenacite and bertrandite， rare earth ore， chrysoberyl，etc. Beryl， the main source of beryllium production in China， is mostly processed using the traditional sulfuric acid method， which suffers from drawbacks such as long process flow， difficulty in lithium-beryllium separation， high beryllium loss， high energy consumption， and poor economic viability. Although the fluorination method offers advantages such as low energy consumption， less corrosion to equipment， and fewer impurities in the product， it is not suitable for ores with high calcium content. Other leaching processes of beryl include direct acid leaching and alkaline leaching. For bertrandite， the sulfuric acid-solvent extraction method is mainly used to separate beryllium and uranium， but it still requires a high-temperature smelting step； thus， researches focus on eliminating the smelting process through methods such as sulfuric acid curing leaching and high-pressure alkaline leaching with silica solidification. The extraction of beryllium from rare earth ores has poor universality and mostly adopts a “leaching first， separation later” approach. Chrysoberyl has high impurity content and stable crystal structure， and no effective method is currently available. Tailings of tungsten， uranium， fluorite， and other minerals often contain beryllium， which are typically leached with sulfuric acid. Beryllium extraction processes generate large amounts of waste such as fly ash and residue， which still contain high levels of beryllium， which can be directly leached by HF or NaOH. Currently， beryllium extraction processes in China face significant challenges， including misalignment between industrial capabilities and national strategic needs， complex procedures， and low recovery rates. There is an urgent need for coordinated efforts in policy guidance， basic research investment， extraction technology development， and resource expansion to achieve green and efficient development of Chinese beryllium resources.
Beryllium resources in China are primarily occur in association with other minerals， exhibiting poor mineralogical characteristics and low utilization rates. China is rich in beryllium resources， but the resources primarily occur in association with other minerals with poor low grades， resulting in low utilization rates. The overall level of development and utilization remains low. As the market demand for beryllium continues to rise， the country is facing a shortage of beryllium supply. With growing scarcity of beryllium resources and rising prices， China faces an impending beryllium supply shortage of beryllium in the future. The main beryllium ore resources include beryl， phenacite and bertrandite， rare earth ore， chrysoberyl，etc. Beryl， the main source of beryllium production in China， is mostly processed using the traditional sulfuric acid method， which suffers from drawbacks such as long process flow， difficulty in lithium-beryllium separation， high beryllium loss， high energy consumption， and poor economic viability. Although the fluorination method offers advantages such as low energy consumption， less corrosion to equipment， and fewer impurities in the product， it is not suitable for ores with high calcium content. Other leaching processes of beryl include direct acid leaching and alkaline leaching. For bertrandite， the sulfuric acid-solvent extraction method is mainly used to separate beryllium and uranium， but it still requires a high-temperature smelting step； thus， researches focus on eliminating the smelting process through methods such as sulfuric acid curing leaching and high-pressure alkaline leaching with silica solidification. The extraction of beryllium from rare earth ores has poor universality and mostly adopts a “leaching first， separation later” approach. Chrysoberyl has high impurity content and stable crystal structure， and no effective method is currently available. Tailings of tungsten， uranium， fluorite， and other minerals often contain beryllium， which are typically leached with sulfuric acid. Beryllium extraction processes generate large amounts of waste such as fly ash and residue， which still contain high levels of beryllium， which can be directly leached by HF or NaOH. Currently， beryllium extraction processes in China face significant challenges， including misalignment between industrial capabilities and national strategic needs， complex procedures， and low recovery rates. There is an urgent need for coordinated efforts in policy guidance， basic research investment， extraction technology development， and resource expansion to achieve green and efficient development of Chinese beryllium resources.
2025, 54(5):1-13.
DOI: 10.19612/j.cnki.cn11-5066/tf.2025.05.001
Abstract:
Nano-micron materials play an important role in the field of new energy. Spray pyrolysis technology is regarded as a promising technique for the industrial-scale production of nano-micro powders, owing to its short process flow, continuous operation, low production cost, and pollution-free reaction. Additionally, spray pyrolysis technology offers advantages such as minimal powder agglomeration, uniform particle size distribution, high specific surface area, controllable chemical composition, and excellent particle flowability, which is widely used in the synthesis of composite materials. This article summarizes research achievements in the preparation of key materials via spray pyrolysis technology, including conductors and catalysts, multi-purpose materials, solar cell materials, lithium-ion battery materials, and fuel cell materials. It was found that most studies focus on exploring the influence of process parameters on the properties of target materials, while some studies focus on synthesizing composite materials with specific structures and optimizing their properties. Currently, achieving large-scale production of fine powders with particle sizes below 5μm is a major challenge for spray pyrolysis technology: powders produced by pneumatic atomization can be easily mass-produced but have larger particle sizes, limiting their industrial application scope; ultrasonic atomization can produce submicron powders (below 5μm) but is difficult to scale up. Based on literature research, future development efforts should focus on two aspects: first, in the technical research domain, there is an urgent need to deepen the understanding of the mechanisms of spray pyrolysis technology and its operational processes; second, in the field of engineering applications, equipment and atomization processes must be optimized and improved, such as enhancing atomization nozzles or incorporating methods to promote particle size reduction. Furthermore, it is essential to actively integrate spray pyrolysis technology with other material preparation techniques to further explore the advantages of combined technologies and improve material performance.
Nano-micron materials play an important role in the field of new energy. Spray pyrolysis technology is regarded as a promising technique for the industrial-scale production of nano-micro powders, owing to its short process flow, continuous operation, low production cost, and pollution-free reaction. Additionally, spray pyrolysis technology offers advantages such as minimal powder agglomeration, uniform particle size distribution, high specific surface area, controllable chemical composition, and excellent particle flowability, which is widely used in the synthesis of composite materials. This article summarizes research achievements in the preparation of key materials via spray pyrolysis technology, including conductors and catalysts, multi-purpose materials, solar cell materials, lithium-ion battery materials, and fuel cell materials. It was found that most studies focus on exploring the influence of process parameters on the properties of target materials, while some studies focus on synthesizing composite materials with specific structures and optimizing their properties. Currently, achieving large-scale production of fine powders with particle sizes below 5μm is a major challenge for spray pyrolysis technology: powders produced by pneumatic atomization can be easily mass-produced but have larger particle sizes, limiting their industrial application scope; ultrasonic atomization can produce submicron powders (below 5μm) but is difficult to scale up. Based on literature research, future development efforts should focus on two aspects: first, in the technical research domain, there is an urgent need to deepen the understanding of the mechanisms of spray pyrolysis technology and its operational processes; second, in the field of engineering applications, equipment and atomization processes must be optimized and improved, such as enhancing atomization nozzles or incorporating methods to promote particle size reduction. Furthermore, it is essential to actively integrate spray pyrolysis technology with other material preparation techniques to further explore the advantages of combined technologies and improve material performance.
2024, 53(1):105-111.
DOI: 10.19612/j.cnki.cn11-5066/tf.2024.01.013
Abstract:
The mixing and mass transfer performance of the multiphase system directly affects the multiphase reaction process. The team developed a new type of tubular stirred reactor that discharges gas from the impeller end. The steady-state sulfite method (FSM) was used to study the gas-liquid mass transfer performance of the reactor. The effects of ventilation flow rate Q, stirring Froude number Fr and liquid content on the volumetric mass transfer coefficient kLa were investigated. The results show that increasing Q and Fr can effectively improve kLa. The new inlet mode can enhance kLa, which is about 2 times higher than that of the traditional reactor. The gas-liquid mass transfer performance of the reactor is highest at ε=0.5, Fr=0.054, Q=1.6m3·h-1, with kLa=0.0324s-1. Based on the experimental data, a dimensionless correlation for kLa was established, and the error was basically within 25%, which has reference significance for improvement and application of the subsequent reactor.
The mixing and mass transfer performance of the multiphase system directly affects the multiphase reaction process. The team developed a new type of tubular stirred reactor that discharges gas from the impeller end. The steady-state sulfite method (FSM) was used to study the gas-liquid mass transfer performance of the reactor. The effects of ventilation flow rate Q, stirring Froude number Fr and liquid content on the volumetric mass transfer coefficient kLa were investigated. The results show that increasing Q and Fr can effectively improve kLa. The new inlet mode can enhance kLa, which is about 2 times higher than that of the traditional reactor. The gas-liquid mass transfer performance of the reactor is highest at ε=0.5, Fr=0.054, Q=1.6m3·h-1, with kLa=0.0324s-1. Based on the experimental data, a dimensionless correlation for kLa was established, and the error was basically within 25%, which has reference significance for improvement and application of the subsequent reactor.
2024(1):1-7.
DOI: 10.19612/j.cnki.cn11-5066/tf.2024.01.001
Abstract:
The ionic liquids formed by 1-ethyl-3-methylimidazole chloride (EMIC) and 1-butyl-3-methylimidazole chloride (BMIC) with aluminum chloride (AlCl3) are the most promising ionic liquids for electrolytic aluminum. In this paper, linear voltammetry, chronoamperometry, chronopotentiometry, constant-voltage electrolysis, constant-current electrolysis and other electrochemical experiments are used to compare the anodic dissolution of aluminum in acidic AlCl3-EMIC and AlCl3-BMIC ionic liquids under stirring and non-stirring conditions, in order to screen out a better electrolyte system. The effects of stirring, temperature, current density, potential and other process parameters on the electrolytic process are investigated to provide basic data for industrial scale-up.
The ionic liquids formed by 1-ethyl-3-methylimidazole chloride (EMIC) and 1-butyl-3-methylimidazole chloride (BMIC) with aluminum chloride (AlCl3) are the most promising ionic liquids for electrolytic aluminum. In this paper, linear voltammetry, chronoamperometry, chronopotentiometry, constant-voltage electrolysis, constant-current electrolysis and other electrochemical experiments are used to compare the anodic dissolution of aluminum in acidic AlCl3-EMIC and AlCl3-BMIC ionic liquids under stirring and non-stirring conditions, in order to screen out a better electrolyte system. The effects of stirring, temperature, current density, potential and other process parameters on the electrolytic process are investigated to provide basic data for industrial scale-up.
2026, 55(1):1-7.
DOI: 10.19612/j.cnki.cn11-5066/tf.2026.01.001
Abstract:
In view of the current situation of wide particle size distribution and lack of high-end production capacity of titanium dioxide by sulfuric acid method in China， in this study， low-concentration industrial titanyl sulfate solution was used as raw material， and authigenic seed hydrolysis process was used to systematically explore the internal regulation mechanism of bottom water volume， titanium liquid TiO2 concentration and curing time on the particle size distribution of metatitanic acid. The structure-activity relationship between the final particle size and structure morphology was analyzed by the characterization results， and the following main conclusions were obtained. The optimal hydrolysis process parameters were as follows： bottom water 16%， titanium solution concentration 205 g/L， and curing time 25 min. Under these conditions， the diameter-to-distance ratio of the prepared metatitanic acid product was as low as 1. 01， which belonged to a narrow particle size distribution and had excellent process stability. The metatitanic acid prepared by hydrolysis is a spherical polycrystalline aggregate formed by the accumulation of （30-60） nm grains through grain boundaries. Due to the adsorption of anions （SO4 2- ， OH- ） on the surface of the crystal nucleus at the initial stage of hydrolysis， the steric hindrance effect and electrostatic repulsion generated hinder the evolution of the crystal nucleus to single crystal， which promotes the formation of a mesoporous hydrated colloidal. The particle size control is based on the multi-stage competitive coupling of 'nucleation-growth-agglomeration'. The bottom water volume reduces the nucleation barrier by adjusting the initial supersaturation and establishes the nucleation advantage. The concentration of TiO2 increases the mass transfer resistance by adjusting the viscosity of the system， and inhibits grain coarsening and hard agglomeration. The ripening time effectively inhibits the particle size broadening caused by the Ostwald ripening effect by regulating the hydrolysis rate. The results can provide production parameters and process reference for industrial preparation of high-performance titanium dioxide.
In view of the current situation of wide particle size distribution and lack of high-end production capacity of titanium dioxide by sulfuric acid method in China， in this study， low-concentration industrial titanyl sulfate solution was used as raw material， and authigenic seed hydrolysis process was used to systematically explore the internal regulation mechanism of bottom water volume， titanium liquid TiO2 concentration and curing time on the particle size distribution of metatitanic acid. The structure-activity relationship between the final particle size and structure morphology was analyzed by the characterization results， and the following main conclusions were obtained. The optimal hydrolysis process parameters were as follows： bottom water 16%， titanium solution concentration 205 g/L， and curing time 25 min. Under these conditions， the diameter-to-distance ratio of the prepared metatitanic acid product was as low as 1. 01， which belonged to a narrow particle size distribution and had excellent process stability. The metatitanic acid prepared by hydrolysis is a spherical polycrystalline aggregate formed by the accumulation of （30-60） nm grains through grain boundaries. Due to the adsorption of anions （SO4 2- ， OH- ） on the surface of the crystal nucleus at the initial stage of hydrolysis， the steric hindrance effect and electrostatic repulsion generated hinder the evolution of the crystal nucleus to single crystal， which promotes the formation of a mesoporous hydrated colloidal. The particle size control is based on the multi-stage competitive coupling of 'nucleation-growth-agglomeration'. The bottom water volume reduces the nucleation barrier by adjusting the initial supersaturation and establishes the nucleation advantage. The concentration of TiO2 increases the mass transfer resistance by adjusting the viscosity of the system， and inhibits grain coarsening and hard agglomeration. The ripening time effectively inhibits the particle size broadening caused by the Ostwald ripening effect by regulating the hydrolysis rate. The results can provide production parameters and process reference for industrial preparation of high-performance titanium dioxide.
2023, 52(2):60-66.
DOI: 10.19612/j.cnki.cn11-5066/tf.2023.02.008
Abstract:
Electrolyte evaporation concentration-cooling crystallization is widely used in copper smelting industry to produce copper sulfate by-products, which is an important purification means to adjust the balance between copper and acid in copper electrolysis process. Common problems such as low evaporation efficiency, long evaporation time and high single steam consumption exist in conventional atmospheric evaporation of copper sulfate. Based on the analysis of the material properties of copper sulfate and the relationship between boiling point and vacuum degree, Southwest Copper Branch has developed a three-effect mixed-flow vacuum evaporation concentration technology for copper sulfate and successfully industrialized. This technology realizes the automatic control of copper sulfate evaporation process, greatly improves the evaporation efficiency of copper sulfate, reduces the steam consumption by 45%, and recovers the secondary steam condensate 120m3/d, creating an annual economic benefit of more than 3 million Yuan. The evaporation system runs well, the quality of copper sulfate products is stable. It has advantages such as high efficiency, energy saving, environmental protection and fully automated production of copper sulfate, which solves the common problems in the industry and has the value of popularization and application.
Electrolyte evaporation concentration-cooling crystallization is widely used in copper smelting industry to produce copper sulfate by-products, which is an important purification means to adjust the balance between copper and acid in copper electrolysis process. Common problems such as low evaporation efficiency, long evaporation time and high single steam consumption exist in conventional atmospheric evaporation of copper sulfate. Based on the analysis of the material properties of copper sulfate and the relationship between boiling point and vacuum degree, Southwest Copper Branch has developed a three-effect mixed-flow vacuum evaporation concentration technology for copper sulfate and successfully industrialized. This technology realizes the automatic control of copper sulfate evaporation process, greatly improves the evaporation efficiency of copper sulfate, reduces the steam consumption by 45%, and recovers the secondary steam condensate 120m3/d, creating an annual economic benefit of more than 3 million Yuan. The evaporation system runs well, the quality of copper sulfate products is stable. It has advantages such as high efficiency, energy saving, environmental protection and fully automated production of copper sulfate, which solves the common problems in the industry and has the value of popularization and application.
2026, 55(1):113-124.
DOI: 10.19612/j.cnki.cn11-5066/tf.2026.01.013
Abstract:
In the process of mixing and dispersion in gas-liquid stirring， the size and distribution of bubbles not only determine the rising velocity of bubbles and the residence time of gas in the liquid phase but also directly affect the gas holdup and the gas-liquid contact area. Many scholars have employed computational fluid dynamics （CFD） to study bubble size distribution， gas content， and liquid velocity， yet none have considered the effects of bubble coalescence and breakup. The population balance model （PBM） reconstructs the bubble size distribution and establishes kernel functions for bubble breakup and coalescence. When combined with CFD， PBM can yield considerably accurate bubble sizes in process equipment such as stirred tanks. This paper employs a CFD-PBM coupled model to investigate the fluid dynamics of the gas-liquid dispersion process in a stirred tank， exploring the effects of rotational speed and gas flow rate on bubble size distribution， flow field， number concentration， and gas holdup. The following key conclusions are drawn. The model demonstrates higher accuracy than Basavarajappa's predictions， with a maximum error of no more than 10% in simulation results， enabling effective prediction of bubble size distribution. The stirring speed significantly influences gas-liquid mixing efficiency， with higher speeds （400 r/min） resulting in smaller and more uniformly distributed bubbles， along with notably enhanced gasliquid mass transfer performance. At low gas flow rates （0. 5 vvm）， bubble generation is limited and unevenly distributed； appropriately increasing the gas flow rate （0. 7 vvm） helps prolong bubble residence time， whereas excessively high flow rates （0. 9 vvm） may lead to bubble coalescence and a decline in mass transfer efficiency. At high rotational speeds （400 r/min）， a noticeable cavitation phenomenon occurs in the back liquid surface area of the stirring blade. This is caused by the aggregation of gases due to local negative pressure， forming stable gas cavities， which adversely affect the stirring efficiency and gas-liquid dispersion effect. By reasonably adjusting the rotational speed and impeller design， the adverse impacts caused by cavitation can be mitigated， thereby further enhancing the stirring efficiency and gas dispersion effect. In actual production， optimizing the stirring speed and gas flow rate can improve bubble distribution and gas-liquid mixing effectiveness.
In the process of mixing and dispersion in gas-liquid stirring， the size and distribution of bubbles not only determine the rising velocity of bubbles and the residence time of gas in the liquid phase but also directly affect the gas holdup and the gas-liquid contact area. Many scholars have employed computational fluid dynamics （CFD） to study bubble size distribution， gas content， and liquid velocity， yet none have considered the effects of bubble coalescence and breakup. The population balance model （PBM） reconstructs the bubble size distribution and establishes kernel functions for bubble breakup and coalescence. When combined with CFD， PBM can yield considerably accurate bubble sizes in process equipment such as stirred tanks. This paper employs a CFD-PBM coupled model to investigate the fluid dynamics of the gas-liquid dispersion process in a stirred tank， exploring the effects of rotational speed and gas flow rate on bubble size distribution， flow field， number concentration， and gas holdup. The following key conclusions are drawn. The model demonstrates higher accuracy than Basavarajappa's predictions， with a maximum error of no more than 10% in simulation results， enabling effective prediction of bubble size distribution. The stirring speed significantly influences gas-liquid mixing efficiency， with higher speeds （400 r/min） resulting in smaller and more uniformly distributed bubbles， along with notably enhanced gasliquid mass transfer performance. At low gas flow rates （0. 5 vvm）， bubble generation is limited and unevenly distributed； appropriately increasing the gas flow rate （0. 7 vvm） helps prolong bubble residence time， whereas excessively high flow rates （0. 9 vvm） may lead to bubble coalescence and a decline in mass transfer efficiency. At high rotational speeds （400 r/min）， a noticeable cavitation phenomenon occurs in the back liquid surface area of the stirring blade. This is caused by the aggregation of gases due to local negative pressure， forming stable gas cavities， which adversely affect the stirring efficiency and gas-liquid dispersion effect. By reasonably adjusting the rotational speed and impeller design， the adverse impacts caused by cavitation can be mitigated， thereby further enhancing the stirring efficiency and gas dispersion effect. In actual production， optimizing the stirring speed and gas flow rate can improve bubble distribution and gas-liquid mixing effectiveness.
2026, 55(1):24-35.
DOI: 10.19612/j.cnki.cn11-5066/tf.2026.01.004
Abstract:
China generates approximately 8 million tons of magnesium slag annually. Constrained by treatment costs and technological limitations， most magnesium slag is currently stored haphazardly or landfilled. Numerous scholars have explored the recent resource utilization of magnesium slag. In this paper， the physical and chemical properties， environmental hazards and resource utilization of magnesium slag are systematically reviewed. The key points and improvement strategies of its application in cementitious materials， cement clinker and carbon sequestration materials are discussed， which provides theoretical support and technical reference for the comprehensive utilization of magnesium slag. Primarily composed of CaO and SiO?， with a mineral composition dominated by β -C ? S and γ -C ? S， magnesium slag has been explored of applications in cementitious materials， ceramics， and carbon sequestration materials. Extensive research exists on magnesium slag as a cementitious material and cement clinker admixture. When used in cementitious materials， it requires synergistic application with other industrial solid wastes to enhance reactivity and improve mechanical properties. Its latent cementitious activity can also be released through physical or chemical activation. As a cement clinker admixture， its dosage impact must be carefully considered. Magnesium slag exhibits promising application potential in high-value-added innovation fields： magnesium slag-based carbon sequestration materials offer advantages such as low cost， high strength， and relative stability， with future applications in road subgrades and mine backfilling； magnesium slag thermal storage ceramics， with their high specific heat capacity and excellent thermal stability， are suitable as heat storage media for solar thermal power generation systems； magnesium slag adsorbents can achieve contaminant removal； magnesium slag can replace traditional precious metals as catalysts， reducing production costs. At present， the actual utilization rate of magnesium slag is still very low. The main problems in the field of cementitious materials are low activity， unstable volume and high cost of excitation technology， which still need to be explored continuously. In the future， the comprehensive utilization of magnesium slag can be studied in high value-added fields and mine filling fields to broaden its available range.
China generates approximately 8 million tons of magnesium slag annually. Constrained by treatment costs and technological limitations， most magnesium slag is currently stored haphazardly or landfilled. Numerous scholars have explored the recent resource utilization of magnesium slag. In this paper， the physical and chemical properties， environmental hazards and resource utilization of magnesium slag are systematically reviewed. The key points and improvement strategies of its application in cementitious materials， cement clinker and carbon sequestration materials are discussed， which provides theoretical support and technical reference for the comprehensive utilization of magnesium slag. Primarily composed of CaO and SiO?， with a mineral composition dominated by β -C ? S and γ -C ? S， magnesium slag has been explored of applications in cementitious materials， ceramics， and carbon sequestration materials. Extensive research exists on magnesium slag as a cementitious material and cement clinker admixture. When used in cementitious materials， it requires synergistic application with other industrial solid wastes to enhance reactivity and improve mechanical properties. Its latent cementitious activity can also be released through physical or chemical activation. As a cement clinker admixture， its dosage impact must be carefully considered. Magnesium slag exhibits promising application potential in high-value-added innovation fields： magnesium slag-based carbon sequestration materials offer advantages such as low cost， high strength， and relative stability， with future applications in road subgrades and mine backfilling； magnesium slag thermal storage ceramics， with their high specific heat capacity and excellent thermal stability， are suitable as heat storage media for solar thermal power generation systems； magnesium slag adsorbents can achieve contaminant removal； magnesium slag can replace traditional precious metals as catalysts， reducing production costs. At present， the actual utilization rate of magnesium slag is still very low. The main problems in the field of cementitious materials are low activity， unstable volume and high cost of excitation technology， which still need to be explored continuously. In the future， the comprehensive utilization of magnesium slag can be studied in high value-added fields and mine filling fields to broaden its available range.
2025, 54(6):1-12.
DOI: 10.19612/j.cnki.cn11-5066/tf.2025.06.001
Abstract:
Pyrometallurgy of non-ferrous metals is the core technology for the industrial extraction of base metals such as copper, lead, zinc and nickel in China. However, its high-temperature, multiphase, and strongly coupled reaction characteristics lead to long-standing issues such as low energy efficiency, high pollutant emissions, and insufficient process control accuracy. As artificial intelligence (AI) technologies continue to penetrate the metallurgical industry, they demonstrate systematic value in improving efficiency, reducing costs, and enhancing safety and environmental performance. This review, from a full-process perspective of “data acquisition-parameter prediction-process optimization-equipment maintenance,” comprehensively explores the implementation of key technologies, including multimodal sensor network construction, critical parameter prediction in high-temperature multiphase systems, multi-objective dynamic optimization control, and intelligent fault diagnosis. Studies show that AI-based methods significantly enhance process energy efficiency and environmental performance by improving the accuracy of online parameter monitoring, strengthening multivariable coordinated control, and enabling full-lifecycle management of critical equipment. Nonetheless, challenges remain, such as fluctuating data quality under extreme thermal conditions, limited model generalization in complex scenarios, and insufficient understanding of multi-scale spatiotemporal coupling mechanisms. Future research should focus on developing physics-informed modeling approaches, cross-scale dynamic optimization algorithms, and industrial-grade intelligent decision systems . Through the deep integration of metallurgical thermodynamics, process systems engineering, and information science, a smart pyrometallurgical technology framework aligned with green and low-carbon goals can be established.
Pyrometallurgy of non-ferrous metals is the core technology for the industrial extraction of base metals such as copper, lead, zinc and nickel in China. However, its high-temperature, multiphase, and strongly coupled reaction characteristics lead to long-standing issues such as low energy efficiency, high pollutant emissions, and insufficient process control accuracy. As artificial intelligence (AI) technologies continue to penetrate the metallurgical industry, they demonstrate systematic value in improving efficiency, reducing costs, and enhancing safety and environmental performance. This review, from a full-process perspective of “data acquisition-parameter prediction-process optimization-equipment maintenance,” comprehensively explores the implementation of key technologies, including multimodal sensor network construction, critical parameter prediction in high-temperature multiphase systems, multi-objective dynamic optimization control, and intelligent fault diagnosis. Studies show that AI-based methods significantly enhance process energy efficiency and environmental performance by improving the accuracy of online parameter monitoring, strengthening multivariable coordinated control, and enabling full-lifecycle management of critical equipment. Nonetheless, challenges remain, such as fluctuating data quality under extreme thermal conditions, limited model generalization in complex scenarios, and insufficient understanding of multi-scale spatiotemporal coupling mechanisms. Future research should focus on developing physics-informed modeling approaches, cross-scale dynamic optimization algorithms, and industrial-grade intelligent decision systems . Through the deep integration of metallurgical thermodynamics, process systems engineering, and information science, a smart pyrometallurgical technology framework aligned with green and low-carbon goals can be established.
2024(1):8-16.
DOI: 10.19612/j.cnki.cn11-5066/tf.2024.01.002
Abstract:
Calcined petroleum coke is an important raw material of metallurgical carbon materials such as carbon anode for aluminum electrolysis. The existing research lacks of in-depth exploration of the microstructure evolution of calcined coke at different calcination temperatures, which makes it difficult to intelligently control and reduce the consumption of metallurgical carbon production. In order to solve the above problems, an intelligent extraction technology of lattice fringes of carbon materials based on HRTEM detection and mathematical fitting were used to investigate the evolution law of the microstructure of calcined coke at different calcination temperatures. When the temperature was below 600℃, the average lattice fringe length, total stacking frequency, and 45° contribution of the calcined cokes slightly deteriorated with the increase of temperature. While in the temperature range of 600 to 1600℃, the variation patterns of the characteristic values were consistent with the Sigmoid function model, which increased rapidly and then gently with the increase of temperature. The effective temperature intervals of the microstructure characteristics were obtained via the deduced formula of the fitting curves. The priority of the microstructure characteristics changing with temperature was as follows: lattice orientation ＞ lattice stacking ＞ lattice growth. The graphitization degree R of calcined coke varied from 0.86 to 0.59 in the temperature range of 25~1600℃ by Raman spectrum analysis. The evolution law of graphitization degree at different temperatures demonstrated the result of the variation patterns analysis of the above microstructure characteristics.
Calcined petroleum coke is an important raw material of metallurgical carbon materials such as carbon anode for aluminum electrolysis. The existing research lacks of in-depth exploration of the microstructure evolution of calcined coke at different calcination temperatures, which makes it difficult to intelligently control and reduce the consumption of metallurgical carbon production. In order to solve the above problems, an intelligent extraction technology of lattice fringes of carbon materials based on HRTEM detection and mathematical fitting were used to investigate the evolution law of the microstructure of calcined coke at different calcination temperatures. When the temperature was below 600℃, the average lattice fringe length, total stacking frequency, and 45° contribution of the calcined cokes slightly deteriorated with the increase of temperature. While in the temperature range of 600 to 1600℃, the variation patterns of the characteristic values were consistent with the Sigmoid function model, which increased rapidly and then gently with the increase of temperature. The effective temperature intervals of the microstructure characteristics were obtained via the deduced formula of the fitting curves. The priority of the microstructure characteristics changing with temperature was as follows: lattice orientation ＞ lattice stacking ＞ lattice growth. The graphitization degree R of calcined coke varied from 0.86 to 0.59 in the temperature range of 25~1600℃ by Raman spectrum analysis. The evolution law of graphitization degree at different temperatures demonstrated the result of the variation patterns analysis of the above microstructure characteristics.
2024, 53(1):17-23.
DOI: 10.19612/j.cnki.cn11-5066/tf.2024.01.003
Abstract:
The electrolysis of lunar soil in cryolite molten salts can realize the in-situ preparation of metals and oxygen, and it is of great significance to study the initial crystal temperature of cryolite molten salts containing lunar soil for the stable operation of the electrolytic cell. In this study, NEU-1 lunar soil simulant prepared from volcanic slag and basalt was used as raw material, mixed with cryolite to obtain electrolyte, which is used as sample to be tested, and the initial crystal temperature of cryolite molten salts with different NEU-1 lunar soil simulant addition and molecular ratios was measured by differential thermal analysis. The results indicated that when the molecular ratio was 2.2, the initial crystal temperature of the cryolite molten salts decreased from 974.9℃ to 932.0℃ with the increase of the addition amount of lunar soil simulant from 0% to 24%. The initial crystal temperature of the cryolite molten salts decreased by 1.79℃ as every 1% of the lunar soil simulant was added. When the addition amount of lunar soil simulant was 8%, the initial crystal temperature of the cryolite molten salts increased from 960.0℃ to 979.4℃ with the increase of molecular ratio from 2.2 to 2.7.
The electrolysis of lunar soil in cryolite molten salts can realize the in-situ preparation of metals and oxygen, and it is of great significance to study the initial crystal temperature of cryolite molten salts containing lunar soil for the stable operation of the electrolytic cell. In this study, NEU-1 lunar soil simulant prepared from volcanic slag and basalt was used as raw material, mixed with cryolite to obtain electrolyte, which is used as sample to be tested, and the initial crystal temperature of cryolite molten salts with different NEU-1 lunar soil simulant addition and molecular ratios was measured by differential thermal analysis. The results indicated that when the molecular ratio was 2.2, the initial crystal temperature of the cryolite molten salts decreased from 974.9℃ to 932.0℃ with the increase of the addition amount of lunar soil simulant from 0% to 24%. The initial crystal temperature of the cryolite molten salts decreased by 1.79℃ as every 1% of the lunar soil simulant was added. When the addition amount of lunar soil simulant was 8%, the initial crystal temperature of the cryolite molten salts increased from 960.0℃ to 979.4℃ with the increase of molecular ratio from 2.2 to 2.7.
2024, 53(1):61-67.
DOI: 10.19612/j.cnki.cn11-5066/tf.2024.01.008
Abstract:
High purity sputtering targets are used as consumables in wafer foundries and LCD panel companies. The utilization rate of high purity sputtering target is low. The utilization rate of general flat targets is less than 30%, and it is difficult for rotating targets to exceed 70%. It is of great economic value and environmental significance to recycle the sputtered residual target. The research status of recovery of high purity target materials such as precious metals, ITO, titanium, tantalum, aluminum and copper were reviewed, and common problems in the recovery process of target materials were summarized. At present, there are still problems that need to be overcome and improved in the residual target recovery of high-purity target materials, such as low metal recovery rate, low purity of recovery, and long process flow, so the author anticipates that developing shorter process, environment-friendly process and exploring high-value uses are the directions for the improvement and development of high-purity residual target recycling and reuse technology in the future.
High purity sputtering targets are used as consumables in wafer foundries and LCD panel companies. The utilization rate of high purity sputtering target is low. The utilization rate of general flat targets is less than 30%, and it is difficult for rotating targets to exceed 70%. It is of great economic value and environmental significance to recycle the sputtered residual target. The research status of recovery of high purity target materials such as precious metals, ITO, titanium, tantalum, aluminum and copper were reviewed, and common problems in the recovery process of target materials were summarized. At present, there are still problems that need to be overcome and improved in the residual target recovery of high-purity target materials, such as low metal recovery rate, low purity of recovery, and long process flow, so the author anticipates that developing shorter process, environment-friendly process and exploring high-value uses are the directions for the improvement and development of high-purity residual target recycling and reuse technology in the future.
2024, 53(1):47-52.
DOI: 10.19612/j.cnki.cn11-5066/tf.2024.01.006
Abstract:
Scandium is an important rare earth element widely used in structural materials such as alloys and ceramics, as well as functional materials such as fuel cell electrolytes and radio frequency filters. In this paper, the preparation methods of scandium fluoride and anhydrous scandium chloride are introduced successively, and then the metal thermal reduction process of scandium halide and the treatment methods of different impurities in crude scandium distillation and purification are described in detail. Then, the further purification and impurity removal methods using zone melting, electromigration and vacuum electron beam melting technologies are discussed. Comparing with calciothermic reduction technology with scandium fluoride, the magnesiothermic reduction technology with scandium chloride to prepare metal scandium has the advantages of low temperature, environmental friendliness and low cost. In the future, the research on the preparation of metal scandium can be focused on the metal thermal reduction of anhydrous scandium chloride. The impurity elements can be removed by multiple high temperature vacuum distillation and electron beam melting, so that the purity of metal scandium can reach 4N or even 5N level. Vacuum electron beam melting, relay zone melting and other technologies have broad development prospects in the preparation of ultra-high purity metal scandium and other rare earth metals.
Scandium is an important rare earth element widely used in structural materials such as alloys and ceramics, as well as functional materials such as fuel cell electrolytes and radio frequency filters. In this paper, the preparation methods of scandium fluoride and anhydrous scandium chloride are introduced successively, and then the metal thermal reduction process of scandium halide and the treatment methods of different impurities in crude scandium distillation and purification are described in detail. Then, the further purification and impurity removal methods using zone melting, electromigration and vacuum electron beam melting technologies are discussed. Comparing with calciothermic reduction technology with scandium fluoride, the magnesiothermic reduction technology with scandium chloride to prepare metal scandium has the advantages of low temperature, environmental friendliness and low cost. In the future, the research on the preparation of metal scandium can be focused on the metal thermal reduction of anhydrous scandium chloride. The impurity elements can be removed by multiple high temperature vacuum distillation and electron beam melting, so that the purity of metal scandium can reach 4N or even 5N level. Vacuum electron beam melting, relay zone melting and other technologies have broad development prospects in the preparation of ultra-high purity metal scandium and other rare earth metals.
2025, 54(5):29-39.
DOI: 10.19612/j.cnki.cn11-5066/tf.2025.05.003
Abstract:
Indium is a high-quality rare and precious metal element. When its purity reaches 99.999% (5N), it is referred to as high-purity indium. High-purity indium exhibits significantly superior performance, stability, and controllability compared to industrial-grade indium, making it highly valuable in advanced fields such as electronic chips and national defense. This paper provides a comprehensive review of various available technologies for the preparation and purification of high-purity indium, along with the latest research progress. The advantages and disadvantages of key methods, including solvent extraction, ion exchange, electrolysis, zone melting, distillation, and adsorption, are critically analyzed. Solvent extraction offers advantages such as energy efficiency and operational convenience, but it requires extensive use of organic solvents and acidic solutions, posing challenges in wastewater treatment and environmental pollution. Ion exchange is widely applied due to its reusability and ease of regeneration; however, its complex preparation technology, high equipment requirements, and elevated costs limit its broader adoption. Future reductions in production costs could significantly enhance its prospects. Electrolysis features simple equipment, environmentally friendly operation, and straightforward procedures, enabling both impurity separation and direct reduction of metal ions via electrons. Nevertheless, its long production cycles, high energy consumption, and the need for post-treatment of electrolyte waste remain drawbacks. Zone melting is highly efficient, energy-saving, and environmentally benign, with a simple and controllable process, yet it demands high-purity raw materials and exhibits limited effectiveness in purifying impurities with partition coefficients close to 1. Distillation is pollution-free and operationally simple but suffers from low efficiency, high equipment and energy costs, and potential generation of hazardous substances during high-temperature processes. Beyond improving existing technologies and optimizing core process parameters, future advancements in high-purity indium purification urgently require the integration of artificial intelligence and the exploration of industrialized pathways for advanced purification techniques.
Indium is a high-quality rare and precious metal element. When its purity reaches 99.999% (5N), it is referred to as high-purity indium. High-purity indium exhibits significantly superior performance, stability, and controllability compared to industrial-grade indium, making it highly valuable in advanced fields such as electronic chips and national defense. This paper provides a comprehensive review of various available technologies for the preparation and purification of high-purity indium, along with the latest research progress. The advantages and disadvantages of key methods, including solvent extraction, ion exchange, electrolysis, zone melting, distillation, and adsorption, are critically analyzed. Solvent extraction offers advantages such as energy efficiency and operational convenience, but it requires extensive use of organic solvents and acidic solutions, posing challenges in wastewater treatment and environmental pollution. Ion exchange is widely applied due to its reusability and ease of regeneration; however, its complex preparation technology, high equipment requirements, and elevated costs limit its broader adoption. Future reductions in production costs could significantly enhance its prospects. Electrolysis features simple equipment, environmentally friendly operation, and straightforward procedures, enabling both impurity separation and direct reduction of metal ions via electrons. Nevertheless, its long production cycles, high energy consumption, and the need for post-treatment of electrolyte waste remain drawbacks. Zone melting is highly efficient, energy-saving, and environmentally benign, with a simple and controllable process, yet it demands high-purity raw materials and exhibits limited effectiveness in purifying impurities with partition coefficients close to 1. Distillation is pollution-free and operationally simple but suffers from low efficiency, high equipment and energy costs, and potential generation of hazardous substances during high-temperature processes. Beyond improving existing technologies and optimizing core process parameters, future advancements in high-purity indium purification urgently require the integration of artificial intelligence and the exploration of industrialized pathways for advanced purification techniques.
2025, 54(2):9-24.
DOI: 10.19612/j.cnki.cn11-5066/tf.2025.02.002
Abstract:
Rare earth metals and their alloys have become essential strategic resources in today's society, and they are mainly prepared by molten salt electrolysis. This paper introduces the research progress on the electrolytic preparation of rare earth metals and their alloys by high-temperature molten salt and room-temperature molten salt (ionic liquids) systems. Regarding the high-temperature molten salt system, it introduces the electrolytic preparation of rare-earth metals by chloride molten salt and fluoride molten salt systems, the electrolytic preparation of rare-earth alloys by different cathodes (inert cathode, active solid cathode, active liquid cathode), and the research progress of China's rare-earth molten salt electrolysis on electrolytic cell, automation and intelligent technology. Regarding the ionic liquids system, the research progress on the electrolytic preparation of rare-earth metals and their alloys by several types of ionic liquids, such as halogen metalate type, air and water stabilized type, task-specific type, and deep eutectic solvent, is introduced. In the high-temperature molten salt system has been realized in a variety of rare earth metals and their alloys of industrial production, but with the “carbon peaking and carbon neutrality goals” strategy continues to promote, rare earth electrolysis, high energy consumption, high emissions of the problem is imminent, the development of energy-saving, environmentally friendly rare earth electrolysis of the new process and equipment is the direction of the future development of rare earth electrolysis. Ionic liquids system electrolysis products are mostly particles or thin films, the preparation of bulk metal is still difficult, continue to develop low-cost ionic liquids with low viscosity, high salt solubility, high stability and other excellent physicochemical properties, for the preparation of low-temperature electrolysis of rare earth metals and their alloys is of great significance.
Rare earth metals and their alloys have become essential strategic resources in today's society, and they are mainly prepared by molten salt electrolysis. This paper introduces the research progress on the electrolytic preparation of rare earth metals and their alloys by high-temperature molten salt and room-temperature molten salt (ionic liquids) systems. Regarding the high-temperature molten salt system, it introduces the electrolytic preparation of rare-earth metals by chloride molten salt and fluoride molten salt systems, the electrolytic preparation of rare-earth alloys by different cathodes (inert cathode, active solid cathode, active liquid cathode), and the research progress of China's rare-earth molten salt electrolysis on electrolytic cell, automation and intelligent technology. Regarding the ionic liquids system, the research progress on the electrolytic preparation of rare-earth metals and their alloys by several types of ionic liquids, such as halogen metalate type, air and water stabilized type, task-specific type, and deep eutectic solvent, is introduced. In the high-temperature molten salt system has been realized in a variety of rare earth metals and their alloys of industrial production, but with the “carbon peaking and carbon neutrality goals” strategy continues to promote, rare earth electrolysis, high energy consumption, high emissions of the problem is imminent, the development of energy-saving, environmentally friendly rare earth electrolysis of the new process and equipment is the direction of the future development of rare earth electrolysis. Ionic liquids system electrolysis products are mostly particles or thin films, the preparation of bulk metal is still difficult, continue to develop low-cost ionic liquids with low viscosity, high salt solubility, high stability and other excellent physicochemical properties, for the preparation of low-temperature electrolysis of rare earth metals and their alloys is of great significance.
2025, 54(6):13-25.
DOI: 10.19612/j.cnki.cn11-5066/tf.2025.06.002
Abstract:
Aiming at the problem that the production state of rare earth electrolytic cell is difficult to perceive, which leads to the inability to accurately control it and affects stable production, this study proposes a hybrid neural network diagnosis model based on signal feature extraction to identify the operation state of electrolytic cell. Firstly, the normalized cell voltage signal is obtained by calculating the cell voltage and cell current, and its time-frequency analysis is carried out to extract the energy values and energy ratios of each frequency band with the time-domain and frequency-domain features in different cell states, and to construct the feature data set. Secondly, a cell state diagnosis model (CNN-BiLSTM-SA) combining convolutional neural network (CNN), bidirectional long-term and short-term memory network (BiLSTM) and self-attention mechanism is established. The local spatial features are captured by CNN, the global dependency is modeled by BiLSTM, and the feature relevance is enhanced by the self-attention mechanism to realize the state diagnosis of the electrolytic cell. Simultaneously, improvements were made to the hippo algorithm by incorporating optimal point set initialization alongside crossover and mutation operations, aiming to enhance the algorithm's hyperparameter optimization capabilities. Finally, the improved hippo algorithm is used to optimize the hyperparameters of the model to improve the diagnostic accuracy of the model. Industrial validation experiments demonstrate that the proposed method achieves a diagnostic accuracy of 94.14% and a Macro-F1 score of 91.08% in cell condition diagnosis. Compared to the unoptimized model, these results represent improvements of 8.28% and 14.19%, respectively. It has advantages in diagnosing the state of rare earth molten salt electrolysis cell, and can provide a basis for optimal control and stable operation of rare earth molten salt electrolysis process.
Aiming at the problem that the production state of rare earth electrolytic cell is difficult to perceive, which leads to the inability to accurately control it and affects stable production, this study proposes a hybrid neural network diagnosis model based on signal feature extraction to identify the operation state of electrolytic cell. Firstly, the normalized cell voltage signal is obtained by calculating the cell voltage and cell current, and its time-frequency analysis is carried out to extract the energy values and energy ratios of each frequency band with the time-domain and frequency-domain features in different cell states, and to construct the feature data set. Secondly, a cell state diagnosis model (CNN-BiLSTM-SA) combining convolutional neural network (CNN), bidirectional long-term and short-term memory network (BiLSTM) and self-attention mechanism is established. The local spatial features are captured by CNN, the global dependency is modeled by BiLSTM, and the feature relevance is enhanced by the self-attention mechanism to realize the state diagnosis of the electrolytic cell. Simultaneously, improvements were made to the hippo algorithm by incorporating optimal point set initialization alongside crossover and mutation operations, aiming to enhance the algorithm's hyperparameter optimization capabilities. Finally, the improved hippo algorithm is used to optimize the hyperparameters of the model to improve the diagnostic accuracy of the model. Industrial validation experiments demonstrate that the proposed method achieves a diagnostic accuracy of 94.14% and a Macro-F1 score of 91.08% in cell condition diagnosis. Compared to the unoptimized model, these results represent improvements of 8.28% and 14.19%, respectively. It has advantages in diagnosing the state of rare earth molten salt electrolysis cell, and can provide a basis for optimal control and stable operation of rare earth molten salt electrolysis process.
2026, 55(1):8-16.
DOI: 10.19612/j.cnki.cn11-5066/tf.2026.01.002
Abstract:
Conventional hydrolysis via the sulfate process produces metatitanic acid exhibiting broad particle size distribution， low specific surface area， and inadequate purity， which severely limits its applicability in high-end fields such as battery materials and catalysis. This study innovatively developed a dispersant-regulated one-step hydrolysis process for preparing metatitanic acid from industrial titanyl sulfate solution. Using a single-factor variable method， we systematically investigated the effects of parameters such as dispersant polyacrylamide（PAM） dosage， stirring speed， and hydrolysis time on metatitanic acid properties. The co-evolution mechanism of particle size distribution and specific surface area of metatitanic acid was explained by experimental results and characterization results， and the following main conclusions were obtained. The optimum hydrolysis process conditions were as follows： PAM dosage 0. 9%， stirring rate 420 r/min， hydrolysis time 2. 65 h. Under these conditions， the average specific surface area of metatitanic acid was 262 m2 /g， the average purity of calcined TiO2 was 99. 58%， and the average particle size range was 2. 65-2. 95 μm， which was better than the food grade standard （GB 1886. 341—2021） and nano grade standard （GB/T 19591—2023）. The prepared metatitanic acid has an anatase TiO2 structure and has colloidal properties. The metatitanic acid contains a large amount of water molecules， hydroxyl groups and sulfate radicals. It is easy to form coarse metatitanic acid aggregates by Ostwald ripening and agglomeration. The porous structure between the aggregates increases the specific surface area of metatitanic acid. The hydrolysis mechanism reveals that the dispersant reduces surface tension through a longchain adsorption layer， inhibits dense particle packing， accelerates nucleation rates， and promotes the formation of fine， porous metatitanic acid. This process is simple， green， and efficient， providing a new pathway for the industrial preparation of battery-grade high-specific-surface-area metatitanic acid and advancing the high-quality development of high-performance titanium dioxide.
Conventional hydrolysis via the sulfate process produces metatitanic acid exhibiting broad particle size distribution， low specific surface area， and inadequate purity， which severely limits its applicability in high-end fields such as battery materials and catalysis. This study innovatively developed a dispersant-regulated one-step hydrolysis process for preparing metatitanic acid from industrial titanyl sulfate solution. Using a single-factor variable method， we systematically investigated the effects of parameters such as dispersant polyacrylamide（PAM） dosage， stirring speed， and hydrolysis time on metatitanic acid properties. The co-evolution mechanism of particle size distribution and specific surface area of metatitanic acid was explained by experimental results and characterization results， and the following main conclusions were obtained. The optimum hydrolysis process conditions were as follows： PAM dosage 0. 9%， stirring rate 420 r/min， hydrolysis time 2. 65 h. Under these conditions， the average specific surface area of metatitanic acid was 262 m2 /g， the average purity of calcined TiO2 was 99. 58%， and the average particle size range was 2. 65-2. 95 μm， which was better than the food grade standard （GB 1886. 341—2021） and nano grade standard （GB/T 19591—2023）. The prepared metatitanic acid has an anatase TiO2 structure and has colloidal properties. The metatitanic acid contains a large amount of water molecules， hydroxyl groups and sulfate radicals. It is easy to form coarse metatitanic acid aggregates by Ostwald ripening and agglomeration. The porous structure between the aggregates increases the specific surface area of metatitanic acid. The hydrolysis mechanism reveals that the dispersant reduces surface tension through a longchain adsorption layer， inhibits dense particle packing， accelerates nucleation rates， and promotes the formation of fine， porous metatitanic acid. This process is simple， green， and efficient， providing a new pathway for the industrial preparation of battery-grade high-specific-surface-area metatitanic acid and advancing the high-quality development of high-performance titanium dioxide.
2024, 53(1):142-152.
DOI: 10.19612/j.cnki.cn11-5066/tf.2024.01.017
Abstract:
The chromium in the electroplating sludge occurred mainly in forms of oxides and/or hydroxides, which could be recovered through a combined process of Na2CO3 assisted oxidizing roasting and water leaching in this research. The results show under the condition of Na2CO3 amount of 100%, roasting temperature of 700℃, and roasting time of 90min, the Cr recovery rate reached 97.8% in the subsequent water leaching process; in a certain range, the Cr recovery rate increased with the increase of Na2CO3 amount, roasting temperature and time; in the Na2S reduction of Na2CrO4 leaching solution, the chromium yield increased with the increase of the amount of Na2S addition, reaction temperature and reaction time; however, excessive Na2S amount would increase the pH of the leaching solution, resulting in the reverse dissolution of Cr2O3 and the decrease of chromium recovery; under the optimized condition of reaction temperature of 60℃, n(CrO2-4)/n(S2-) of 8∶9, and reaction time of 80min, the chromium recovery reached 92.3%. The study achieved an efficient recovery of chromium from electroplated sludge.
The chromium in the electroplating sludge occurred mainly in forms of oxides and/or hydroxides, which could be recovered through a combined process of Na2CO3 assisted oxidizing roasting and water leaching in this research. The results show under the condition of Na2CO3 amount of 100%, roasting temperature of 700℃, and roasting time of 90min, the Cr recovery rate reached 97.8% in the subsequent water leaching process; in a certain range, the Cr recovery rate increased with the increase of Na2CO3 amount, roasting temperature and time; in the Na2S reduction of Na2CrO4 leaching solution, the chromium yield increased with the increase of the amount of Na2S addition, reaction temperature and reaction time; however, excessive Na2S amount would increase the pH of the leaching solution, resulting in the reverse dissolution of Cr2O3 and the decrease of chromium recovery; under the optimized condition of reaction temperature of 60℃, n(CrO2-4)/n(S2-) of 8∶9, and reaction time of 80min, the chromium recovery reached 92.3%. The study achieved an efficient recovery of chromium from electroplated sludge.
2024, 53(1):153-160.
DOI: 10.19612/j.cnki.cn11-5066/tf.2024.01.018
Abstract:
Waste printed circuit boards are rich in metal and non-metal resources, which have high resource recovery value and potential environmental hazards. In this study, under the conventional and microwave pyrolysis conditions, the influence of the detinning pretreatment and related pyrolysis conditions on the distribution and mechanism of pyrolysis products were studied. The results show that detinning pretreatment has a positive effect on the pyrolysis of waste computer circuit boards, which can make the organic materials in the waste circuit boards pyrolyze more fully. After detinning pretreatment, the Sn content is reduced from 4.10% to 1.54%, and the recovery rate of Sn can be reached 68.49%. Under conventional and microwave pyrolysis conditions, more liquid and gas products can be obtained with the temperature increasing, but more solid products can be obtained by microwave pyrolysis at the same temperature.After conventional pyrolysis, the copper content increased from 19.17% before pyrolysis to 25.37%, and after microwave pyrolysis, the copper content increased from 19.17% before pyrolysis to 23.32%.And the recovery rate of copper is over 99.22%. After pyrolysis, most of the bromine element enters the pyrolysis oil and pyrolysis gas. The content of phenolic in microwave pyrolysis oil is greater than that of conventional pyrolysis, and the content of furans is less than that of conventional pyrolysis. The pyrolysis gas contains a large amount of combustible gas. The total amount of H2, CO and CH4 in the conventional and microwave pyrolysis gas reach 76.4% and 80.7%, respectively. The heating value of the pyrolysis gas is 18.78MJ/Nm3 and 19.97MJ/Nm3, respectively. The calorific value of pyrolysis gas is between coal gas and natural gas and can be used as gas. Comprehensive comparison between conventional pyrolysis and microwave pyrolysis, microwave pyrolysis has a higher metal recovery rate, less furans in the pyrolysis gas, and a higher calorific value of the pyrolysis gas, which is more conducive to the comprehensive recovery of valuable metals in electronic waste use.
Waste printed circuit boards are rich in metal and non-metal resources, which have high resource recovery value and potential environmental hazards. In this study, under the conventional and microwave pyrolysis conditions, the influence of the detinning pretreatment and related pyrolysis conditions on the distribution and mechanism of pyrolysis products were studied. The results show that detinning pretreatment has a positive effect on the pyrolysis of waste computer circuit boards, which can make the organic materials in the waste circuit boards pyrolyze more fully. After detinning pretreatment, the Sn content is reduced from 4.10% to 1.54%, and the recovery rate of Sn can be reached 68.49%. Under conventional and microwave pyrolysis conditions, more liquid and gas products can be obtained with the temperature increasing, but more solid products can be obtained by microwave pyrolysis at the same temperature.After conventional pyrolysis, the copper content increased from 19.17% before pyrolysis to 25.37%, and after microwave pyrolysis, the copper content increased from 19.17% before pyrolysis to 23.32%.And the recovery rate of copper is over 99.22%. After pyrolysis, most of the bromine element enters the pyrolysis oil and pyrolysis gas. The content of phenolic in microwave pyrolysis oil is greater than that of conventional pyrolysis, and the content of furans is less than that of conventional pyrolysis. The pyrolysis gas contains a large amount of combustible gas. The total amount of H2, CO and CH4 in the conventional and microwave pyrolysis gas reach 76.4% and 80.7%, respectively. The heating value of the pyrolysis gas is 18.78MJ/Nm3 and 19.97MJ/Nm3, respectively. The calorific value of pyrolysis gas is between coal gas and natural gas and can be used as gas. Comprehensive comparison between conventional pyrolysis and microwave pyrolysis, microwave pyrolysis has a higher metal recovery rate, less furans in the pyrolysis gas, and a higher calorific value of the pyrolysis gas, which is more conducive to the comprehensive recovery of valuable metals in electronic waste use.
2025(6):108-114.
DOI: 10.19612/j.cnki.cn11-5066/tf.2025.06.010
Abstract:
The third generation sulfuric acid rare earth separation process uses a lot of magnesium ions, which produces a lot of transformed magnesium sulfate wastewater. The wastewater contains SO2-4, saturated calcium sulfate, Mg2+, oil and suspended solids, and the water quality is unstable, so it is difficult to treat. Traditional lime neutralization method and traditional evaporation concentration method have some problems, such as high treatment cost and low efficiency, which lead to the treatment of rare earth magnesium sulfate wastewater has been in a blank state. This paper proposes a green process route of “calcium hydroxide neutralization-reuse of rare earth leaching”, and conducts research from three aspects: neutralization and impurity removal of magnesium sulfate wastewater, rare earth recovery rate in the neutralization liquid leaching process of sulfate rare earth, and moisture content of tailings. The following main conclusions are obtained. The process of neutralizing magnesium sulfate wastewater by calcium hydroxide is mainly affected by the pH value of the solution， when the wastewater pH is 9.5, the content of SO2-4 is 80.5g/L, the content of Mg2+ decreases to 14.7g/L, and the addition of calcium hydroxide is the smallest. The pH value of neutralization solution has a great influence on the water content of leaching tailings. When the pH value is large, the water content is low and the cake forming degree is good, when pH=9.5, the leaching rate of rare earth did not decrease obviously, and the water content of rare earth tailings reached 42.3% (the water content required for production was less than 43.0%), which reached the standard of entering the tailings pond. Conventional stirring is adopted in this process, because when the concentration of sulfate radical is more than 85.0g/L, the soluble complex formed by Ce4+, SO2-4 and Mg2+ is destroyed by high-shear stirring, so that tetravalent cerium and magnesium sulfate wastewater form flocs to precipitate, blocking the water flow channel of filter cake and affecting solid-liquid separation.Using this method to neutralize magnesium sulfate wastewater and then reuse it in rare earth calcine leaching process, rare earth leaching is not affected, and magnesium sulfate wastewater can be recycled.
The third generation sulfuric acid rare earth separation process uses a lot of magnesium ions, which produces a lot of transformed magnesium sulfate wastewater. The wastewater contains SO2-4, saturated calcium sulfate, Mg2+, oil and suspended solids, and the water quality is unstable, so it is difficult to treat. Traditional lime neutralization method and traditional evaporation concentration method have some problems, such as high treatment cost and low efficiency, which lead to the treatment of rare earth magnesium sulfate wastewater has been in a blank state. This paper proposes a green process route of “calcium hydroxide neutralization-reuse of rare earth leaching”, and conducts research from three aspects: neutralization and impurity removal of magnesium sulfate wastewater, rare earth recovery rate in the neutralization liquid leaching process of sulfate rare earth, and moisture content of tailings. The following main conclusions are obtained. The process of neutralizing magnesium sulfate wastewater by calcium hydroxide is mainly affected by the pH value of the solution， when the wastewater pH is 9.5, the content of SO2-4 is 80.5g/L, the content of Mg2+ decreases to 14.7g/L, and the addition of calcium hydroxide is the smallest. The pH value of neutralization solution has a great influence on the water content of leaching tailings. When the pH value is large, the water content is low and the cake forming degree is good, when pH=9.5, the leaching rate of rare earth did not decrease obviously, and the water content of rare earth tailings reached 42.3% (the water content required for production was less than 43.0%), which reached the standard of entering the tailings pond. Conventional stirring is adopted in this process, because when the concentration of sulfate radical is more than 85.0g/L, the soluble complex formed by Ce4+, SO2-4 and Mg2+ is destroyed by high-shear stirring, so that tetravalent cerium and magnesium sulfate wastewater form flocs to precipitate, blocking the water flow channel of filter cake and affecting solid-liquid separation.Using this method to neutralize magnesium sulfate wastewater and then reuse it in rare earth calcine leaching process, rare earth leaching is not affected, and magnesium sulfate wastewater can be recycled.
