The rapid development of novel energy materials has led to a sustained surge in the global demand for fluorine.Fluorite is the primary source of fluorine globally and is increasingly being exploited.The estimated annu...The rapid development of novel energy materials has led to a sustained surge in the global demand for fluorine.Fluorite is the primary source of fluorine globally and is increasingly being exploited.The estimated annual production of fluorite worldwide is approximately 8 million tons,with an additional 5 million tons of fluorite tailings.This accumulation not only consumes land resources,but also contributes to dust generation and F-percolation,leading to water and air contamination.This paper comprehensively reviews the utilization methods of fluorite tailings,including the flotation recovery of quartz and fluorite,the preparation of cement mineralizing agents,and the preparation of concrete mineral additives,autoclaved lime sand brick,and glass-ceramics.Furthermore,potential future applications and research directions are proposed,including the comprehensive recovery of valuable minerals,auxiliary cementitious materials preparation,and the functionalization of glass-ceramics.This study can serve as a reference for expediting the utilization of fluorite tailings,promoting the development of tailing-free mines,and establishing sustainable development strategies.展开更多
A process for treating cyanide tailings was proposed.The process essentially implicates reduction smelting which involves volatilizing silver,lead,and zinc in the cyanide tailings at high temperatures.Meanwhile,gold a...A process for treating cyanide tailings was proposed.The process essentially implicates reduction smelting which involves volatilizing silver,lead,and zinc in the cyanide tailings at high temperatures.Meanwhile,gold and copper combine with the reduced iron to form a metal phase,allowing for the simultaneous recovery of polymetallic elements.The experimental results indicate that the process works optimally with a coke powder of 7.5 wt.%,an alkalinity of 1.0,a melting temperature of 1450℃,and a melting time of 60 min.Under these conditions,more than 99% of gold,77% of copper and 94% of iron are incorporated into pig iron.In the meantime,the volatilization rate of silver exceeds 90%,while lead and zinc are essentially completely volatilized.The primary component of the by-product smelting slag is akermanite,which exhibits lower leaching toxicity than the national standard and belongs to general solid waste.Additionally,taking the trapping process of iron to copper as a case study,the mechanism of iron trapping is methodically examined and divided into three processes:smelting reduction,migration capture,and condensation deposition.展开更多
Specialized vanadium(V)-iron(Fe)-based alloy additives utilized in the production of V-containing steels were investigated.Vanadium slag from the Panzhihua region of China was utilized as a raw material to optimize pr...Specialized vanadium(V)-iron(Fe)-based alloy additives utilized in the production of V-containing steels were investigated.Vanadium slag from the Panzhihua region of China was utilized as a raw material to optimize process parameters for the preparation of V-Fe-based alloy via silicon thermal reduction.Experiments were conducted to investigate the effects of reduction temperature,holding time,and slag composition on alloy-slag separation,alloy microstructure,and the oxide content of residual slag,with an emphasis on the recovery of valuable metal elements.The results indicated that the optimal process conditions for silicon thermal reduction were achieved at reduction temperature of 1823 K,holding time of 240 min,and slag composition of 45 wt.%SiO_(2),40 wt.%CaO,and 15 wt.%Al_(2)O_(3).The resulting V-Fe-based alloy predominantly consisted of Fe-based phases such as Fe,titanium(Ti),silicon(Si)and manganese(Mn),with Si,V,as well as chromium(Cr)concentrated in the intercrystalline phase of the Fe-based alloy.The recoveries of Fe,Mn,Cr,V,and Ti under the optimal conditions were 96.30%,91.96%,86.53%,80.29%,and 74.82%,respectively.The key components of the V-Fe-based alloy obtained were 41.96 wt.%Si,27.55 wt.%Fe,12.13 wt.%Mn,5.53 wt.%V,4.86 wt.%Cr,and 3.74 wt.%Ti,thereby enabling the comprehensive recovery of the valuable metal from vanadium slag.展开更多
一、参照对比,其意自明1.英语中多义词很多,如何确定某个关键词在句子中的确切含义,有时字典是帮不了很多忙。一个在实践中行之有效的方法是在句子中找到同它关系密切的词,与之参照对比,往往能够得出十分贴切的含义。例如:Automation ha...一、参照对比,其意自明1.英语中多义词很多,如何确定某个关键词在句子中的确切含义,有时字典是帮不了很多忙。一个在实践中行之有效的方法是在句子中找到同它关系密切的词,与之参照对比,往往能够得出十分贴切的含义。例如:Automation has been,and still is,agreatly misused word,but its propermeaning,and therefore its implications,展开更多
A coordinative disposal process for treatment of electroplating sludge and stainless steel pickle waste liquid containing Cu, Ni, Zn, Cr and Fe etc., has been developed to recover valuable metals and to eliminate poll...A coordinative disposal process for treatment of electroplating sludge and stainless steel pickle waste liquid containing Cu, Ni, Zn, Cr and Fe etc., has been developed to recover valuable metals and to eliminate pollution. The recovery of Cu, Ni, Zn and Cr is 94%, 91%, 90% and 95%, respectively. The ammonia was recycled by the simplified process of CaO caustic distillation. The precipitated product of Cu, Ni and Zn obtained from caustic distillation of ammonia was separated by extraction or high\|pressure hydrogen reduction in an autoclave. The qualified metal salt products were obtained through extraction. The rich chromium residue from coordinative disposal was subjected to recover Cr by hydrothermal oxidation in NaOH medium and Fe\-3O\-4 was synthesized by wet methods from the residue produced by extracting Cr. Cr was a stable chemical fixed in Fe\-3O\-4 and harmless. The recovery process has been used in a pilot plant with sludge production capacity of 2000 t/a.展开更多
The number of lithium-ion batteries(LIBs)is steadily increasing in order to meet the ever-growing demand for sustainable energy and a high quality of life for humankind.At the same time,the resulting large number of L...The number of lithium-ion batteries(LIBs)is steadily increasing in order to meet the ever-growing demand for sustainable energy and a high quality of life for humankind.At the same time,the resulting large number of LIB waste certainly poses safety hazards if it is not properly disposed of and will seriously harm the environment due to its inherent toxicity due to the use of toxic substances.Moreover,the consumption of many scarce precious metal resources is behind the mass production of batteries.In the light of severe environmental,resources,safety and recycling problems,recycling spent LIBs have become an essential urgently needed action to achieve sustainable social development.This review therefore critically analyses the value and the need for recycling of spent LIBs from a variety of resources and the environment.A range of existing technologies for recycling and reusing spent LIBs,such as pretreatment,pyrometallurgy,hydrometallurgy,and direct recycled methods,is subsequently summarized exclusively.In addition,the benefits and problems of the methods described above are analyzed in detail.It also introduces recycling progress of other LIB components,such as anodes,separators,and electrolytes,as well as the high-value cathode.Finally,the prospects for recycling LIBs are addressed in four ways(government,users,battery manufacturers,and recyclers).This review should contribute to the development of the recycling of used LIBs,particularly in support of industrialization and recycling processes.展开更多
Zinc leaching residue(ZLR),produced from traditional zinc hydrometallurgy process,is not only a hazardous waste but also a potential valuable solid.The combination of sulfate roasting and water leaching was employed t...Zinc leaching residue(ZLR),produced from traditional zinc hydrometallurgy process,is not only a hazardous waste but also a potential valuable solid.The combination of sulfate roasting and water leaching was employed to recover the valuable metals from ZLR.The ZLR was initially roasted with ferric sulfate at640°C for1h with ferric sulfate/zinc ferrite mole ratio of1.2.In this process,the valuable metals were efficiently transformed into water soluble sulfate,while iron remains as ferric oxide.Thereafter,water leaching was conducted to extract the valuable metals sulfate for recovery.The recovery rates of zinc,manganese,copper,cadmium and iron were92.4%,93.3%,99.3%,91.4%and1.1%,respectively.A leaching toxicity test for ZLR was performed after water leaching.The results indicated that the final residue was effectively detoxified and all of the heavy metal leaching concentrations were under the allowable limit.展开更多
With the aim of high-efficiency utilization of Dandong ludwigite ore, a new process of metallizing reduction and mag- netic separation was proposed, and the effects of reduction temperature, reduction time, carbon rat...With the aim of high-efficiency utilization of Dandong ludwigite ore, a new process of metallizing reduction and mag- netic separation was proposed, and the effects of reduction temperature, reduction time, carbon ratio, ore size and coal size on the efficiency of the process were investigated in details, and relevant mechanisms were elucidated by SEM and EDS. The optimum technological parameters for metallizing reduction and magnetic separation on ludwigite ore were obtained as reduction tempera- ture of 1 250 ℃, reduction time of 60 min, carbon ratio of 1.4, ore size of 0.500-2.000 mm, and coal size of 0.50-1.50 mm. After adopting the optimum parameters, the iron content and recovery ratio of iron in magnetic substance are 87.78% and 88.02%, re- spectively, while the recovery ratios of boron, magnesium and silicon in non-magnetic substance are 88.86%, 94.60% and 98.66%, respectively. After metallizing reduction and magnetic separation, valuable elements of ludwigite ore could be separated and uti- lized in subsequent steelmaking process and hydrometallurgy process.展开更多
The abundant genetic resources of wild rice in China represent a key gene pool for modern rice breeding,contributing to food production and agricultural development in China and worldwide.Between the 1970s and the 201...The abundant genetic resources of wild rice in China represent a key gene pool for modern rice breeding,contributing to food production and agricultural development in China and worldwide.Between the 1970s and the 2010s,two national wild rice surveys were carried out in China.More than 20000accessions of three species Oryza rufipogon,O.officinalis and O.meyeriana have been conserved ex situ.An in situ conservation system has also been set up to protect notable and endangered populations.This review summarized the geographical distribution of wild rice in China,the current status of conservation,the discovery of elite genes,and the application of research into the origin and domestication of rice.展开更多
Copper-indium-gallium-diselenide(CIGS)is a fast-evolving commercial solar cell.The firm demand for global carbon reduction and the rise of potential environmental threats necessitate spent CIGS solar cell recycling.In...Copper-indium-gallium-diselenide(CIGS)is a fast-evolving commercial solar cell.The firm demand for global carbon reduction and the rise of potential environmental threats necessitate spent CIGS solar cell recycling.In this paper,the sources and characteristics of valuable metals in spent CIGS solar cells were reviewed.The potential environmental impacts of CIGS,including service life,critical material,and material toxicity,were outlined.The main recovery methods of valuable metals in the various types of spent CIGS,including hydrometallurgy,pyrometallurgy,and comprehensive treatment processes,were compared and discussed.The mechanism of different recovery processes was summarized.The challenges faced by different recycling processes of spent CIGS were also covered in this review.Finally,the economic viability of the recycling process was assessed.The purpose of this review is to provide reasonable suggestions for the sustainable development of CIGS and the harmless disposal of spent CIGS.展开更多
An orthogonal array,L16(45),was used to examine the effects of four parameters,including NaCl concentration,H2SO4 concentration,temperature and pulp density,on the recovery of Cu,In,Pb and Zn from a hydrometallurgical...An orthogonal array,L16(45),was used to examine the effects of four parameters,including NaCl concentration,H2SO4 concentration,temperature and pulp density,on the recovery of Cu,In,Pb and Zn from a hydrometallurgical residue via brine leaching.The results show that temperature of leaching solution has a significant effect on the recovery of Cu,In and Zn,while H2SO4 concentration has an obvious influence on these metals extraction.Both pulp density and NaCl concentration significantly affect Pb extraction.Based on the orthogonal array experiments,the optimum conditions for the extraction of Cu,In,Pb and Zn from hydrometallurgical residue are NaCl concentration of 250 g/L,H2SO4 concentration of 1.00 mol/L,temperature of 85℃,and pulp density of 100 g/L.After 1 h of treatment at these optimum conditions,over 91% of the metals are extracted from the residue.Brine leaching is therefore suitable for the recovery of metals from hydrometallurgical residues.展开更多
The recycling of waste printed circuit board(WPCBs) is of great significance for saving resources and protecting the environment. In this study, the WPCBs were pyrolyzed by microwave and the contained valuable metals ...The recycling of waste printed circuit board(WPCBs) is of great significance for saving resources and protecting the environment. In this study, the WPCBs were pyrolyzed by microwave and the contained valuable metals Cu, Sn and Pb were recovered from the pyrolyzed WPCBs. The effect of pyrolysis temperature and time on the recovery efficiency of valuable metals was investigated. Additionally, the characterization for morphology and surface elemental distribution of pyrolysis residues was carried out to investigate the pyrolysis mechanism. The plastic fiber boards turned into black carbides, and they can be easily separated from the metals by manual. The results indicate that 91.2%, 96.1% and 94.4% of Cu, Sn and Pb can be recovered after microwave pyrolysis at 700 °C for 60 minutes. After pyrolysis, about 79.8%(mass)solid products, 11.9%(mass) oil and 8.3%(mass) gas were produced. These gas and oil can be used as fuel and raw materials of organic chemicals, respectively. This process provides an efficient and energy-saving technology for recovering valuable metals from WPCBs.展开更多
We present management tools for growing four valuable broadleaved tree species, indigenous to subtropi.cal southern China. Crown diameter （CD） of the species studied can be predicted very well by using a model that ...We present management tools for growing four valuable broadleaved tree species, indigenous to subtropi.cal southern China. Crown diameter （CD） of the species studied can be predicted very well by using a model that is so e y a near funct on of d ameter at breast he ght （DBH）. The add t on of tree age （AGE） and yield class （YC） to this-nodel did not significantly improve its predictive capacity. We used species-specific crown diameter models to calcu- ate the amount of growing space and subsequently stand density that each species needs to achieve desired stem ＂adial growth rates. Furthermore we used this information to calculate a ＂distance factor＂, a rule of thumb that roughly ~stimates the distance between two neighboring trees needed to achieve a desired future target diameter. These tools ＇acilitate the planning of thinning regimes by using crown diameter models combined with annual radial growth rates to ;alculate the number of crop trees per hectare required to reach a desired target stem diameter.展开更多
Conservation of ancient and large trees in domestic and overseas cities was compared, ancient and large trees were regarded as important cultural relics playing an important role in optimizing urban natural environmen...Conservation of ancient and large trees in domestic and overseas cities was compared, ancient and large trees were regarded as important cultural relics playing an important role in optimizing urban natural environment and enriching urban humanistic and natural landscapes, and they were also important contents of urban garden works symbolizing urban parks. A case study was carried out Yunqizhujing Park to study conservation of ancient and large trees in park green spaces of Hangzhou City, solutions to current problems were proposed, and constructive suggestions were given for the conservation of ancient and large trees in urban park green spaces.展开更多
Ternary lithium-ion batteries(LIBs),widely used in new energy vehicles and electronic products,are known for their high en-ergy density,wide operating temperature range,and excellent cycling performance.With the rapid...Ternary lithium-ion batteries(LIBs),widely used in new energy vehicles and electronic products,are known for their high en-ergy density,wide operating temperature range,and excellent cycling performance.With the rapid development of the battery industry,the recycling of spent ternary LIBs has become a hot topic because of their economic value and environmental concerns.To date,a con-siderable amount of literature has reported on the recycling of spent ternary LIBs designed to provide an efficient,economical,and envir-onmentally friendly method for battery recycling.This article examines the latest developments in various technologies for recycling spent ternary LIBs in both research and practical production,including pretreatment,pyrometallurgy,hydrometallurgy,pyro-hydrometallurgy,and direct regeneration.Suggestions for addressing challenges based on the benefits and disadvantages of each method are made.Finally,through a comparison of the feasibility and economic benefits of various technologies,the challenges faced during battery recycling are summarized,and future development directions are proposed.展开更多
Physicochemical and mineralogical characteristics of an alkali leaching residue of wolframite were studied by XRD,SEM−EDS,chemical phase analysis,mineral liberation analyzer(MLA),and TG−DSC methods.Batch leaching test...Physicochemical and mineralogical characteristics of an alkali leaching residue of wolframite were studied by XRD,SEM−EDS,chemical phase analysis,mineral liberation analyzer(MLA),and TG−DSC methods.Batch leaching tests,toxicity characteristic leaching procedure(TCLP)tests and Chinese standard leaching tests(CSLT)were conducted to determine the environmental mobility of toxic elements.The results show that,due to the high contents of W,Fe,Mn,Sn,and Nb,the residue is with high resource value,but the content of a toxic element,As,is also high.The existing minerals of the investigated elements mainly occur as monomer particles,but it is difficult to extract these valuable metals by conventional acid leaching due to their mineral properties.The release of As increases over time in acidic environment.The leaching concentration of all investigated harmful elements through TCLP is within the limiting value,while the leaching concentration of As through CSLT exceeds the limiting value by more than 4 times,so the residue is classified as hazardous solid waste based on the Chinese standard.A process for valuable metals recovery from this residue was proposed.Preliminary experimental results indicated that the main valuable metals could be extracted effectively.展开更多
Lead, zinc, and iron were recovered from jarosite residues using direct reduction followed by magnetic separation. The influence of the coal dosage, reduction temperature, and reduction time on the volatilization rate...Lead, zinc, and iron were recovered from jarosite residues using direct reduction followed by magnetic separation. The influence of the coal dosage, reduction temperature, and reduction time on the volatilization rates of lead and zinc and the metallization rate of iron were investigated. The results show that the volatilization rates of lead and zinc were 96.97% and 99.89%, respectively, and the iron metallization rate was 91.97% under the optimal reduction roasting conditions of a coal dosage of 25.0 wt% and reduction roasting at 1250°C for 60 min. The magnetic concentrate with an iron content of 90.59 wt% and an iron recovery rate of 50.87% was obtained under the optimum conditions in which 96.56% of the reduction product particles were smaller than 37 μm and the magnetic field strength was 24 k A/m. Therefore, the results of this study demonstrate that recovering valuable metals such as lead, zinc, and iron from jarosite residues is feasible using the developed approach.展开更多
The global importance of lithium-ion batteries(LIBs)has been increasingly underscored with the advancement of high-performance energy storage technologies.However,the end-of-life of these batteries poses significant c...The global importance of lithium-ion batteries(LIBs)has been increasingly underscored with the advancement of high-performance energy storage technologies.However,the end-of-life of these batteries poses significant challenges from environmental,economic,and resource management perspectives.This review paper focuses on the pyrometallurgy-based recycling process of lithium-ion batteries,exploring the fundamental understanding of this process and the importance of its optimization.Centering on the high energy consumption and emission gas issues of the pyrometallurgical recycling process,we systematically analyzed the capital-intensive nature of this process and the resulting technological characteristics.Furthermore,we conducted an in-depth discussion on the future research directions to overcome the existing technological barriers and limitations.This review will provide valuable insights for researchers and industry stakeholders in the battery recycling field.展开更多
The lithium-ion batteries(LIBs)have been widely equipped in electric/hybrid electric vehicles(EVs/HEVs)and the portable electronics due to their excellent electrochemical performances.However,a large number of retired...The lithium-ion batteries(LIBs)have been widely equipped in electric/hybrid electric vehicles(EVs/HEVs)and the portable electronics due to their excellent electrochemical performances.However,a large number of retired LIBs that consist of toxic substances(e.g.,heavy metals,electrolytes)and valuable metals(e.g.,Li,Co)will inevitably flow into the waste stream,and their incineration or landfill treatment will cause severe risks to ecosystem and human beings.The sustainable and efficient treatment or recycling of valuable resources from spent LIBs should be fully recognized for environmental and resource security.As one of the most important processes for spent LIBs recycling,the pretreatment is an indispensable step,which is directly related to the subsequent metal extraction and separation processes.Although considerable progresses have been made regarding the pretreatment technologies,there are few summarized reports concerning critical processes of spent LIBs recycling,especially combination of currently available recycling technologies with industrialized applications during pretreatments.Therefore,comprehensive review of the current prevailing pretreatment technologies in laboratory to existing scale-up applications is quite necessary to reveal cutting-edge development in the field of pretreatment.In this review,the current pretreatment technologies are systematically categorized and introduced,along with critical discussions.This review focused on the various options for pretreatment processes itself,instead of general spent LIBs recycling technologies without the focused topics that have been sophisticatedly reviewed by previous studies.Here,the deactivation,discharge,dismantling,separation,liberation of active material and electrolyte treatment have been summarized with the in-depth discussion of the technology development and current status of each category.Finally,current states of industrial development are also reviewed and discussed for the development of efficient and environmentally friendly recycling technologies for future applications.This review tends to present a focused topic concerning the pretreatment of spent LIBs to potential readers with a comprehensive illustration of the development on both cutting-edge technologies and scale-up applications.展开更多
基金supported by the National Key Research and Development Program of China(No.2023YFC3903901)the Key Research and Development Program of Hubei Province,CHina(No.2022BAA029)the Science and Technology Project of Shaanxi Yanchang Petroleum(Group)Co.,Ltd.,China(No.yc-whlg-2023ky-03).
文摘The rapid development of novel energy materials has led to a sustained surge in the global demand for fluorine.Fluorite is the primary source of fluorine globally and is increasingly being exploited.The estimated annual production of fluorite worldwide is approximately 8 million tons,with an additional 5 million tons of fluorite tailings.This accumulation not only consumes land resources,but also contributes to dust generation and F-percolation,leading to water and air contamination.This paper comprehensively reviews the utilization methods of fluorite tailings,including the flotation recovery of quartz and fluorite,the preparation of cement mineralizing agents,and the preparation of concrete mineral additives,autoclaved lime sand brick,and glass-ceramics.Furthermore,potential future applications and research directions are proposed,including the comprehensive recovery of valuable minerals,auxiliary cementitious materials preparation,and the functionalization of glass-ceramics.This study can serve as a reference for expediting the utilization of fluorite tailings,promoting the development of tailing-free mines,and establishing sustainable development strategies.
基金supported by the National Key R&D Program of China(No.2020YFC1909203)the Hunan Provincial Innovation Project,China(No.CX20230213)。
文摘A process for treating cyanide tailings was proposed.The process essentially implicates reduction smelting which involves volatilizing silver,lead,and zinc in the cyanide tailings at high temperatures.Meanwhile,gold and copper combine with the reduced iron to form a metal phase,allowing for the simultaneous recovery of polymetallic elements.The experimental results indicate that the process works optimally with a coke powder of 7.5 wt.%,an alkalinity of 1.0,a melting temperature of 1450℃,and a melting time of 60 min.Under these conditions,more than 99% of gold,77% of copper and 94% of iron are incorporated into pig iron.In the meantime,the volatilization rate of silver exceeds 90%,while lead and zinc are essentially completely volatilized.The primary component of the by-product smelting slag is akermanite,which exhibits lower leaching toxicity than the national standard and belongs to general solid waste.Additionally,taking the trapping process of iron to copper as a case study,the mechanism of iron trapping is methodically examined and divided into three processes:smelting reduction,migration capture,and condensation deposition.
基金the financial support provided by the National Key R&D Program of China(Grant No.2023YFC3903900)the Science and Technology Innovation Talent Program of Hubei Province(Grant No.2022EJD002)+1 种基金the Sichuan Science and Technology Program(Grant No.2025ZNSFSC0378)the Key Laboratory of Green Chemistry of Sichuan Institutes of Higher Education(Grant No.LZJ2303).
文摘Specialized vanadium(V)-iron(Fe)-based alloy additives utilized in the production of V-containing steels were investigated.Vanadium slag from the Panzhihua region of China was utilized as a raw material to optimize process parameters for the preparation of V-Fe-based alloy via silicon thermal reduction.Experiments were conducted to investigate the effects of reduction temperature,holding time,and slag composition on alloy-slag separation,alloy microstructure,and the oxide content of residual slag,with an emphasis on the recovery of valuable metal elements.The results indicated that the optimal process conditions for silicon thermal reduction were achieved at reduction temperature of 1823 K,holding time of 240 min,and slag composition of 45 wt.%SiO_(2),40 wt.%CaO,and 15 wt.%Al_(2)O_(3).The resulting V-Fe-based alloy predominantly consisted of Fe-based phases such as Fe,titanium(Ti),silicon(Si)and manganese(Mn),with Si,V,as well as chromium(Cr)concentrated in the intercrystalline phase of the Fe-based alloy.The recoveries of Fe,Mn,Cr,V,and Ti under the optimal conditions were 96.30%,91.96%,86.53%,80.29%,and 74.82%,respectively.The key components of the V-Fe-based alloy obtained were 41.96 wt.%Si,27.55 wt.%Fe,12.13 wt.%Mn,5.53 wt.%V,4.86 wt.%Cr,and 3.74 wt.%Ti,thereby enabling the comprehensive recovery of the valuable metal from vanadium slag.
文摘一、参照对比,其意自明1.英语中多义词很多,如何确定某个关键词在句子中的确切含义,有时字典是帮不了很多忙。一个在实践中行之有效的方法是在句子中找到同它关系密切的词,与之参照对比,往往能够得出十分贴切的含义。例如:Automation has been,and still is,agreatly misused word,but its propermeaning,and therefore its implications,
文摘A coordinative disposal process for treatment of electroplating sludge and stainless steel pickle waste liquid containing Cu, Ni, Zn, Cr and Fe etc., has been developed to recover valuable metals and to eliminate pollution. The recovery of Cu, Ni, Zn and Cr is 94%, 91%, 90% and 95%, respectively. The ammonia was recycled by the simplified process of CaO caustic distillation. The precipitated product of Cu, Ni and Zn obtained from caustic distillation of ammonia was separated by extraction or high\|pressure hydrogen reduction in an autoclave. The qualified metal salt products were obtained through extraction. The rich chromium residue from coordinative disposal was subjected to recover Cr by hydrothermal oxidation in NaOH medium and Fe\-3O\-4 was synthesized by wet methods from the residue produced by extracting Cr. Cr was a stable chemical fixed in Fe\-3O\-4 and harmless. The recovery process has been used in a pilot plant with sludge production capacity of 2000 t/a.
基金financially supported by the National Natural Science Foundation of China(No.52173246)the 111 Project(B13013).
文摘The number of lithium-ion batteries(LIBs)is steadily increasing in order to meet the ever-growing demand for sustainable energy and a high quality of life for humankind.At the same time,the resulting large number of LIB waste certainly poses safety hazards if it is not properly disposed of and will seriously harm the environment due to its inherent toxicity due to the use of toxic substances.Moreover,the consumption of many scarce precious metal resources is behind the mass production of batteries.In the light of severe environmental,resources,safety and recycling problems,recycling spent LIBs have become an essential urgently needed action to achieve sustainable social development.This review therefore critically analyses the value and the need for recycling of spent LIBs from a variety of resources and the environment.A range of existing technologies for recycling and reusing spent LIBs,such as pretreatment,pyrometallurgy,hydrometallurgy,and direct recycled methods,is subsequently summarized exclusively.In addition,the benefits and problems of the methods described above are analyzed in detail.It also introduces recycling progress of other LIB components,such as anodes,separators,and electrolytes,as well as the high-value cathode.Finally,the prospects for recycling LIBs are addressed in four ways(government,users,battery manufacturers,and recyclers).This review should contribute to the development of the recycling of used LIBs,particularly in support of industrialization and recycling processes.
基金Project(2014FJ1011)supported by Key Project of Science and Technology of Hunan Province,ChinaProject(201509050)supported by Program for Special Scientific Research Projects of National Public Welfare Industry
文摘Zinc leaching residue(ZLR),produced from traditional zinc hydrometallurgy process,is not only a hazardous waste but also a potential valuable solid.The combination of sulfate roasting and water leaching was employed to recover the valuable metals from ZLR.The ZLR was initially roasted with ferric sulfate at640°C for1h with ferric sulfate/zinc ferrite mole ratio of1.2.In this process,the valuable metals were efficiently transformed into water soluble sulfate,while iron remains as ferric oxide.Thereafter,water leaching was conducted to extract the valuable metals sulfate for recovery.The recovery rates of zinc,manganese,copper,cadmium and iron were92.4%,93.3%,99.3%,91.4%and1.1%,respectively.A leaching toxicity test for ZLR was performed after water leaching.The results indicated that the final residue was effectively detoxified and all of the heavy metal leaching concentrations were under the allowable limit.
基金Sponsored by the Specialized Research Fund for the Doctoral Program of Higher Education of China(20100042110004)Fundamental Research Funds for the Central Universities of China(090502004,140206003)
文摘With the aim of high-efficiency utilization of Dandong ludwigite ore, a new process of metallizing reduction and mag- netic separation was proposed, and the effects of reduction temperature, reduction time, carbon ratio, ore size and coal size on the efficiency of the process were investigated in details, and relevant mechanisms were elucidated by SEM and EDS. The optimum technological parameters for metallizing reduction and magnetic separation on ludwigite ore were obtained as reduction tempera- ture of 1 250 ℃, reduction time of 60 min, carbon ratio of 1.4, ore size of 0.500-2.000 mm, and coal size of 0.50-1.50 mm. After adopting the optimum parameters, the iron content and recovery ratio of iron in magnetic substance are 87.78% and 88.02%, re- spectively, while the recovery ratios of boron, magnesium and silicon in non-magnetic substance are 88.86%, 94.60% and 98.66%, respectively. After metallizing reduction and magnetic separation, valuable elements of ludwigite ore could be separated and uti- lized in subsequent steelmaking process and hydrometallurgy process.
基金supported by the National Natural Science Foundation of China(Grant No.31471471)the Project of Sanya Yazhou Bay Science and Technology City,China(Grant No.SKJC-2020-02-001)。
文摘The abundant genetic resources of wild rice in China represent a key gene pool for modern rice breeding,contributing to food production and agricultural development in China and worldwide.Between the 1970s and the 2010s,two national wild rice surveys were carried out in China.More than 20000accessions of three species Oryza rufipogon,O.officinalis and O.meyeriana have been conserved ex situ.An in situ conservation system has also been set up to protect notable and endangered populations.This review summarized the geographical distribution of wild rice in China,the current status of conservation,the discovery of elite genes,and the application of research into the origin and domestication of rice.
基金financially supported by the Beijing Natural Science Foundation of China (No. 2232038)the National Natural Science Foundation of China (Nos. 52034002 and U1802253)the Fundamental Research Funds for the Central Universities (No. FRF-TT-19-001)
文摘Copper-indium-gallium-diselenide(CIGS)is a fast-evolving commercial solar cell.The firm demand for global carbon reduction and the rise of potential environmental threats necessitate spent CIGS solar cell recycling.In this paper,the sources and characteristics of valuable metals in spent CIGS solar cells were reviewed.The potential environmental impacts of CIGS,including service life,critical material,and material toxicity,were outlined.The main recovery methods of valuable metals in the various types of spent CIGS,including hydrometallurgy,pyrometallurgy,and comprehensive treatment processes,were compared and discussed.The mechanism of different recovery processes was summarized.The challenges faced by different recycling processes of spent CIGS were also covered in this review.Finally,the economic viability of the recycling process was assessed.The purpose of this review is to provide reasonable suggestions for the sustainable development of CIGS and the harmless disposal of spent CIGS.
基金Project(20507022) supported by the National Natural Science Foundation of China
文摘An orthogonal array,L16(45),was used to examine the effects of four parameters,including NaCl concentration,H2SO4 concentration,temperature and pulp density,on the recovery of Cu,In,Pb and Zn from a hydrometallurgical residue via brine leaching.The results show that temperature of leaching solution has a significant effect on the recovery of Cu,In and Zn,while H2SO4 concentration has an obvious influence on these metals extraction.Both pulp density and NaCl concentration significantly affect Pb extraction.Based on the orthogonal array experiments,the optimum conditions for the extraction of Cu,In,Pb and Zn from hydrometallurgical residue are NaCl concentration of 250 g/L,H2SO4 concentration of 1.00 mol/L,temperature of 85℃,and pulp density of 100 g/L.After 1 h of treatment at these optimum conditions,over 91% of the metals are extracted from the residue.Brine leaching is therefore suitable for the recovery of metals from hydrometallurgical residues.
基金supported by the National Key Research and Development Program of China (2019YFC1908404)the National Natural Science Foundation of China (Nos. 51834008, 51874040,52034002)+1 种基金the Guangxi Innovation-Driven Development Project(AA18242042-1)the Fundamental Research Funds for the Central Universities (FRF-TP-18-020A3)。
文摘The recycling of waste printed circuit board(WPCBs) is of great significance for saving resources and protecting the environment. In this study, the WPCBs were pyrolyzed by microwave and the contained valuable metals Cu, Sn and Pb were recovered from the pyrolyzed WPCBs. The effect of pyrolysis temperature and time on the recovery efficiency of valuable metals was investigated. Additionally, the characterization for morphology and surface elemental distribution of pyrolysis residues was carried out to investigate the pyrolysis mechanism. The plastic fiber boards turned into black carbides, and they can be easily separated from the metals by manual. The results indicate that 91.2%, 96.1% and 94.4% of Cu, Sn and Pb can be recovered after microwave pyrolysis at 700 °C for 60 minutes. After pyrolysis, about 79.8%(mass)solid products, 11.9%(mass) oil and 8.3%(mass) gas were produced. These gas and oil can be used as fuel and raw materials of organic chemicals, respectively. This process provides an efficient and energy-saving technology for recovering valuable metals from WPCBs.
基金supported by the German Federal Ministry of Education and Research (BMBF) (No. 0330802A)the Chinese Ministry of Science and Technology (MOST) (No. 2008DFA32070) in the framework of the Sino-German joint project "ValWood-innovative sustainable land use"
文摘We present management tools for growing four valuable broadleaved tree species, indigenous to subtropi.cal southern China. Crown diameter （CD） of the species studied can be predicted very well by using a model that is so e y a near funct on of d ameter at breast he ght （DBH）. The add t on of tree age （AGE） and yield class （YC） to this-nodel did not significantly improve its predictive capacity. We used species-specific crown diameter models to calcu- ate the amount of growing space and subsequently stand density that each species needs to achieve desired stem ＂adial growth rates. Furthermore we used this information to calculate a ＂distance factor＂, a rule of thumb that roughly ~stimates the distance between two neighboring trees needed to achieve a desired future target diameter. These tools ＇acilitate the planning of thinning regimes by using crown diameter models combined with annual radial growth rates to ;alculate the number of crop trees per hectare required to reach a desired target stem diameter.
基金Supported by Lin’an Scientific and Technological Program of Zhejiang Province(200933)Hangzhou Social Development Scientific Research Program of Zhejiang Province(20100933B34)
文摘Conservation of ancient and large trees in domestic and overseas cities was compared, ancient and large trees were regarded as important cultural relics playing an important role in optimizing urban natural environment and enriching urban humanistic and natural landscapes, and they were also important contents of urban garden works symbolizing urban parks. A case study was carried out Yunqizhujing Park to study conservation of ancient and large trees in park green spaces of Hangzhou City, solutions to current problems were proposed, and constructive suggestions were given for the conservation of ancient and large trees in urban park green spaces.
基金sponsored by the National Natural Science Foundation of China(Nos.52204412 and U2002212)the National Key R&D Program of China(No.2021YFC 1910504)the Fundamental Research Funds for the Central Universities(No.FRF-TP-20-031A1).
文摘Ternary lithium-ion batteries(LIBs),widely used in new energy vehicles and electronic products,are known for their high en-ergy density,wide operating temperature range,and excellent cycling performance.With the rapid development of the battery industry,the recycling of spent ternary LIBs has become a hot topic because of their economic value and environmental concerns.To date,a con-siderable amount of literature has reported on the recycling of spent ternary LIBs designed to provide an efficient,economical,and envir-onmentally friendly method for battery recycling.This article examines the latest developments in various technologies for recycling spent ternary LIBs in both research and practical production,including pretreatment,pyrometallurgy,hydrometallurgy,pyro-hydrometallurgy,and direct regeneration.Suggestions for addressing challenges based on the benefits and disadvantages of each method are made.Finally,through a comparison of the feasibility and economic benefits of various technologies,the challenges faced during battery recycling are summarized,and future development directions are proposed.
基金the financial supports from the National Key R&D Program of China(No.2019YFC1907400)the National Natural Science Foundation of China(Nos.51904351,51620105013)。
文摘Physicochemical and mineralogical characteristics of an alkali leaching residue of wolframite were studied by XRD,SEM−EDS,chemical phase analysis,mineral liberation analyzer(MLA),and TG−DSC methods.Batch leaching tests,toxicity characteristic leaching procedure(TCLP)tests and Chinese standard leaching tests(CSLT)were conducted to determine the environmental mobility of toxic elements.The results show that,due to the high contents of W,Fe,Mn,Sn,and Nb,the residue is with high resource value,but the content of a toxic element,As,is also high.The existing minerals of the investigated elements mainly occur as monomer particles,but it is difficult to extract these valuable metals by conventional acid leaching due to their mineral properties.The release of As increases over time in acidic environment.The leaching concentration of all investigated harmful elements through TCLP is within the limiting value,while the leaching concentration of As through CSLT exceeds the limiting value by more than 4 times,so the residue is classified as hazardous solid waste based on the Chinese standard.A process for valuable metals recovery from this residue was proposed.Preliminary experimental results indicated that the main valuable metals could be extracted effectively.
文摘Lead, zinc, and iron were recovered from jarosite residues using direct reduction followed by magnetic separation. The influence of the coal dosage, reduction temperature, and reduction time on the volatilization rates of lead and zinc and the metallization rate of iron were investigated. The results show that the volatilization rates of lead and zinc were 96.97% and 99.89%, respectively, and the iron metallization rate was 91.97% under the optimal reduction roasting conditions of a coal dosage of 25.0 wt% and reduction roasting at 1250°C for 60 min. The magnetic concentrate with an iron content of 90.59 wt% and an iron recovery rate of 50.87% was obtained under the optimum conditions in which 96.56% of the reduction product particles were smaller than 37 μm and the magnetic field strength was 24 k A/m. Therefore, the results of this study demonstrate that recovering valuable metals such as lead, zinc, and iron from jarosite residues is feasible using the developed approach.
基金the Technology Innovation Program(or Industrial Strategic Technology Development Program)and the Ministry of Trade,Industry&Energy(MOTIE)of the Republic of Korea(No.20022950)。
文摘The global importance of lithium-ion batteries(LIBs)has been increasingly underscored with the advancement of high-performance energy storage technologies.However,the end-of-life of these batteries poses significant challenges from environmental,economic,and resource management perspectives.This review paper focuses on the pyrometallurgy-based recycling process of lithium-ion batteries,exploring the fundamental understanding of this process and the importance of its optimization.Centering on the high energy consumption and emission gas issues of the pyrometallurgical recycling process,we systematically analyzed the capital-intensive nature of this process and the resulting technological characteristics.Furthermore,we conducted an in-depth discussion on the future research directions to overcome the existing technological barriers and limitations.This review will provide valuable insights for researchers and industry stakeholders in the battery recycling field.
基金financially supported by the National Natural Science Foundation of China(Nos.52074177 and 52174391)Hunan Provincial Science and Technology Plan,China(No.2017TP1001)。
文摘The lithium-ion batteries(LIBs)have been widely equipped in electric/hybrid electric vehicles(EVs/HEVs)and the portable electronics due to their excellent electrochemical performances.However,a large number of retired LIBs that consist of toxic substances(e.g.,heavy metals,electrolytes)and valuable metals(e.g.,Li,Co)will inevitably flow into the waste stream,and their incineration or landfill treatment will cause severe risks to ecosystem and human beings.The sustainable and efficient treatment or recycling of valuable resources from spent LIBs should be fully recognized for environmental and resource security.As one of the most important processes for spent LIBs recycling,the pretreatment is an indispensable step,which is directly related to the subsequent metal extraction and separation processes.Although considerable progresses have been made regarding the pretreatment technologies,there are few summarized reports concerning critical processes of spent LIBs recycling,especially combination of currently available recycling technologies with industrialized applications during pretreatments.Therefore,comprehensive review of the current prevailing pretreatment technologies in laboratory to existing scale-up applications is quite necessary to reveal cutting-edge development in the field of pretreatment.In this review,the current pretreatment technologies are systematically categorized and introduced,along with critical discussions.This review focused on the various options for pretreatment processes itself,instead of general spent LIBs recycling technologies without the focused topics that have been sophisticatedly reviewed by previous studies.Here,the deactivation,discharge,dismantling,separation,liberation of active material and electrolyte treatment have been summarized with the in-depth discussion of the technology development and current status of each category.Finally,current states of industrial development are also reviewed and discussed for the development of efficient and environmentally friendly recycling technologies for future applications.This review tends to present a focused topic concerning the pretreatment of spent LIBs to potential readers with a comprehensive illustration of the development on both cutting-edge technologies and scale-up applications.
