Tailings from the vanadium extraction process are discarded each year as waste,which contain approximately 30 wt%of Fe.In our previous work,we extracted Fe and Mn from vanadium slag,and Fe and Mn existed in the form o...Tailings from the vanadium extraction process are discarded each year as waste,which contain approximately 30 wt%of Fe.In our previous work,we extracted Fe and Mn from vanadium slag,and Fe and Mn existed in the form of FeCl_(2) and MnCl_(2) after chlorination by NH_(4) Cl to achieve effective and green usage of waste containing Fe and Mn.In this work,square wave voltammetry(SWV)and cyclic voltammetry(CV)were applied to investigate the electrochemical behaviors of Fe^(2+)and Mn^(2+)in Na Cl-KCl melt at 800℃.The reduction processes of Fe^(2+)and Mn^(2+)were found to involve one step.The diffusion coefficients of FeCl_(2) and Mn Cl_(2) in molten salt of eutectic mixtures Na Cl-KCl molten salt were measured.The electrodeposition of Fe and Mn were performed using two electrodes at a constant cell voltage.The Mn/Fe mass ratio of the electrodeposited product in Na Cl-KCl-2.13 wt%FeCl_(2)-1.07 wt%Mn Cl_(2) was 0.0625 at 2.3 V.After the electrolysis of NaCl-KCl-2.13 wt%Fe Cl_(2)-1.07 wt%MnCl_(2) melted at 2.3 V,the electrolysis was again started under 3.0 V and the Mn/Fe mass ratio of the electrodeposited product was 36.4.This process provides a novel method to effectively separate Fe and Mn from simulated chlorinated vanadium slag.展开更多
The physicochemical properties of the system, such as density, surface tension, specific conductance and melting point were measured. The results were discussed.
To improve the separation capacity of uranium in aqueous solutions, 3R-MoS2 nanosheets were prepared with molten salt electro- lysis and further modified with polypyrrole (PPy) to synthesize a hybrid nanoadsorbent (PP...To improve the separation capacity of uranium in aqueous solutions, 3R-MoS2 nanosheets were prepared with molten salt electro- lysis and further modified with polypyrrole (PPy) to synthesize a hybrid nanoadsorbent (PPy/3R-MoS2). The preparation conditions of PPy/3R- MoS2 were investigated and the obtained nanosheets were characterized with scanning electron microscope (SEM), high resolution transmis- sion electron microscope (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectro- scopy (XPS). The results showed that PPy/3R-MoS2 exhibited enhanced adsorption capacity toward U(VI) compared to pure 3R-MoS2 and PPy;the maximum adsorption was 200.4 mg/g. The adsorption mechanism was elucidated with XPS and FTIR: (1) negatively charged PPy/3R-MoS2 nanosheets attracted by an electrostatic interaction;(2) exposed C, N, Mo, and S atoms complexed with U(VI) through co- ordination;(3) Mo in the complex partly reduced the adsorbed U(VI) to U(IV), which further regenerated the adsorption point and continu- ously adsorbed U(VI). The design of the PPy/3R-MoS2 composite with a high adsorption capacity and chemical stability provides a new direc- tion for the removal of radionuclide.展开更多
Silicon(Si)and carbon(C)composites hold the promise for replacing the commercial graphite anode,thus increasing the energy density of lithium-ion batteries(LIBs).To mitigate the formation of SiC,this paper reports a m...Silicon(Si)and carbon(C)composites hold the promise for replacing the commercial graphite anode,thus increasing the energy density of lithium-ion batteries(LIBs).To mitigate the formation of SiC,this paper reports a molten salt electrolysis approach to prepare C-Si composite by the electrolysis of C-SiO2 composites.Unlike the conventional way of making a C coating on Si,C-SiO2 composites were prepared by pyrolyzing the low-cost sucrose and silica.The electrochemical deoxidation of the C-SiO2 composites not only produces nanostructured Si inside the C matrix but also introduces voids between the C and Si owing to the volume shrinkage from converting SiO2 to Si.More importantly,the use of Mg ion-containing molten salts precludes the generation of SiC,and the electrolytic Si@C composite anode delivers a capacity of about 1500 mAh g-1 after 100 cycles at a current density of 500 mA g-1.Further,the Si@C‖LiNi0.6Co0.2Mn0.2O2 full cell delivers a high energy density of 608 Wh kg-1.Overall,the molten salt approach provides a one-step electrochemical way to convert oxides@C to metals@C functional materials.展开更多
Molten salt is an excellent medium for chemical reaction,energy transfer,and storage.Molten salt innovative technologies should be developed to recover metals from secondary resources and reserve metals from primary n...Molten salt is an excellent medium for chemical reaction,energy transfer,and storage.Molten salt innovative technologies should be developed to recover metals from secondary resources and reserve metals from primary natural sources.Among these technologies,molten salt electrolysis is an economic and environment-friendly method to extract metals from waste materials.From the perspective of molten salt characteristics,the application of molten salts in chemistry,electrochemistry,energy,and thermal storage should be comprehensively elaborated.This review discusses further directions for the research and development of molten salt electrolysis and their use for metal recovery from various metal wastes,such as magnet scrap,nuclear waste,and cemented carbide scrap.Attention is placed on the development of various electrolysis methods for different metal containing wastes,overcoming some problems in electrolytes,electrodes,and electrolytic cells.Special focus is given to future development directions for current associated processing obstacles.展开更多
With the increasing demand of rare earth metals in functional materials,recovery of rare earth elements(REEs)from secondary resources has become important for the green economy transition.Molten salt electrolysis has ...With the increasing demand of rare earth metals in functional materials,recovery of rare earth elements(REEs)from secondary resources has become important for the green economy transition.Molten salt electrolysis has the advantages of low water consumption and low hazardous waste during REE recovery.This review systematically summarizes the separation and electroextraction of REEs on various reactive electrodes in different molten salts.It also highlights the relationship between the formed alloy phases and electrodeposition parameters,including applied potential,current,and ion concentration.Moreover,the feasibility of using LiF–NaF–KF electrolyte to recover REEs is evaluated through thermodynamic analysis.Problems related to REE separation/recovery the choice of electrolyte are discussed in detail to realize the low-energy and high current efficiency of practical applications.展开更多
Spent catalyst used for denitration by selective catalytic reduction(spent SCR denitration catalysts) is one of the important urban mines due to the high content of TiO_(2)(~85 wt%) and the massive accumulation amount...Spent catalyst used for denitration by selective catalytic reduction(spent SCR denitration catalysts) is one of the important urban mines due to the high content of TiO_(2)(~85 wt%) and the massive accumulation amount(over 100,000 tons),therefore,value-added reutilization of titanium in spent SCR catalysts is considerably meaningful.In this paper,a novel method is proposed for converting the titanium oxide in spent SCR denitration catalysts to metallic titanium.Specifically,titanium dioxide(TiO_(2)) was firstly obtained from spent SCR denitration catalysts after removing the impurities by hydrometallurgy process.Then,TiO_(2) is converted to Ti_(2)CO by carbothermic reduction method,and Ti_(2)CO was further purified by oleic acid capture.Finally,by utilizing the as-prepared Ti_(2)CO as the consumable anode in the NaCl-KCl molten salt,high-purity metallic titanium was deposited at cathode,all confirming the feasibility for the conversion of low-grade TiO_(2) in the spent catalysts,from 60 wt% to high-purity metallic Ti(99.5 wt%), furthermore,the energy consumption of this process is 3950 kWh tonne-1 Ti,which is lower than that of most traditional titanium metallurgy methods.The method herein can provide new insights for the value-added recycling of titanium resources in urban mines.展开更多
A novel and environmentally friendly route to directly prepare metallic vanadium from Na VO_3 by molten salt electrolysis is proposed.The feasibility about the direct electro-reduction of NaVO_3 to metallic vanadium i...A novel and environmentally friendly route to directly prepare metallic vanadium from Na VO_3 by molten salt electrolysis is proposed.The feasibility about the direct electro-reduction of NaVO_3 to metallic vanadium is analyzed based on the thermodynamic calculations and experimental veri fications.The theoretical decomposition voltage of NaVO_3 to metallic vanadium is only 0.47 Vat 800°C and much lower than that of the alkali and alkali earth metal chloride salts.The value is slightly higher than that of low-valence vanadium oxides such as V_2O_3,V_3O_5 and VO.However,the low-valence vanadium oxides can be further electro-reduced to metallic vanadium thermodynamically.The thermodynamic analysis is veri fied by the experimental results.The direct preparation of metallic vanadium from NaVO_3 by molten salt electrolysis is feasible.展开更多
The electrochemical behaviour of copper electrode in molten NaCl-KCl-LaCl<sub>3</sub> has been investigated.TheLa-Cu alloy is formed at first and then the metallic lanthanum is deposited when the La<sup...The electrochemical behaviour of copper electrode in molten NaCl-KCl-LaCl<sub>3</sub> has been investigated.TheLa-Cu alloy is formed at first and then the metallic lanthanum is deposited when the La<sup>3+</sup>is reduced on thecopper electrode.The technological conditions of preparing La-Cu alloy by consumable cathode have been dis-cussed.The La-Cu alloy contained lanthanum over 90wt% was obtained.The composition of alloy was LaCu<sub>2</sub>and La.The current efficiency was 85% and the recovery of lanthanum was near 90%.展开更多
Electrocatalytic oxygen evolution reaction(OER)has been recognized as the bottleneck of overall water splitting,which is a promising approach for sustainable production of H_(2).Transition metal(TM)hydroxides are the ...Electrocatalytic oxygen evolution reaction(OER)has been recognized as the bottleneck of overall water splitting,which is a promising approach for sustainable production of H_(2).Transition metal(TM)hydroxides are the most conventional and classical non-noble metal-based electrocatalysts for OER,while TM basic salts[M^(2+)(OH)_(2-x)(A_(m^(-))_(x/m),A=CO_(3)^(2−),NO_(3)^(−),F^(−),Cl^(−)]consisting of OH−and another anion have drawn extensive research interest due to its higher catalytic activity in the past decade.In this review,we summarize the recent advances of TM basic salts and their application in OER and further overall water splitting.We categorize TM basic salt-based OER pre-catalysts into four types(CO_(3)^(2−),NO_(3)^(−),F^(−),Cl^(−)according to the anion,which is a key factor for their outstanding performance towards OER.We highlight experimental and theoretical methods for understanding the structure evolution during OER and the effect of anion on catalytic performance.To develop bifunctional TM basic salts as catalyst for the practical electrolysis application,we also review the present strategies for enhancing its hydrogen evolution reaction activity and thereby improving its overall water splitting performance.Finally,we conclude this review with a summary and perspective about the remaining challenges and future opportunities of TM basic salts as catalysts for water electrolysis.展开更多
In a thorium-based molten salt reactor(TMSR),it is difficult to achieve the pure 232Th–^(233)U fuel cycle without sufficient^(233)U fuel supply.Therefore,the original molten salt reactor was designed to use enriched ...In a thorium-based molten salt reactor(TMSR),it is difficult to achieve the pure 232Th–^(233)U fuel cycle without sufficient^(233)U fuel supply.Therefore,the original molten salt reactor was designed to use enriched uranium or plutonium as the starting fuel.By exploiting plutonium as the starting fuel and thorium as the fertile fuel,the high-purity^(233)U produced can be separated from the spent fuel by fluorination volatilization.Therefore,the molten salt reactor started with plutonium can be designed as a^(233)U breeder with the burning plutonium extracted from a pressurized water reactor(PWR).Combining these advantages,the study of the physical properties of plutonium-activated salt reactors is attractive.This study mainly focused on the burnup performance and temperature reactivity coefficient of a small modular molten-salt reactor started with plutonium(SM-MSR-Pu).The neutron spectra,^(233)U production,plutonium incineration,minor actinide(MA)residues,and temperature reactivity coefficients for different fuel salt volume fractions(VF)and hexagon pitch(P)sizes were calculated to analyze the burnup behavior in the SM-SMR-Pu.Based on the comparative analysis results of the burn-up calculation,a lower VF and larger P size are more beneficial for improving the burnup performance.However,from a passive safety perspective,a higher fuel volume fraction and smaller hexagon pitch size are necessary to achieve a deep negative feedback coefficient.Therefore,an excellent burnup performance and a deep negative temperature feedback coefficient are incompatible,and the optimal design range is relatively narrow in the optimized design of an SM-MSR-Pu.In a comprehensive consideration,P=20 cm and VF=20%are considered to be relatively balanced design parameters.Based on the fuel off-line batching scheme,a 250 MWth SM-MSR-Pu can produce approximately 29.83 kg of ^(233)U,incinerate 98.29 kg of plutonium,and accumulate 14.70 kg of MAs per year,and the temperature reactivity coefficient can always be lower than−4.0pcm/K.展开更多
Electrodeposition of magnesium-yttrium alloys from molten salts was studied by electrochemical techniques.LiF-YF3 was electrolyte system with magnesium oxide and Yttrium oxide as raw materials.It was proved that Mg2+ ...Electrodeposition of magnesium-yttrium alloys from molten salts was studied by electrochemical techniques.LiF-YF3 was electrolyte system with magnesium oxide and Yttrium oxide as raw materials.It was proved that Mg2+ and Y3+was deposited more prior than other ions during cyclic voltammetry and potential step measurement at 1050 °C.Voltammograms showed Mg2+ could be deposited at-0.5 V,and Y3+ could be deposited at-0.7 V on tungsten electrode compared with platinum electrode.The sedimentation of Mg2+ was more positive about 230 mV than that of other ions in electrolyte.The electrolytic codeposition of yttrium and magnesium was 0.58 V on condition that the weight ratio of Y2O3/MgO was 4:1.Chronopotentiogram indicated that the process of electrodeposition of magnesium-yttrium alloys on tungsten electrode was controlled by diffusion of ions from electrolyte to electrode interface.It was feasible to prepare Magnesium-Yttrium alloys by controlling content of ions in molten salt electrolyte.展开更多
Different phases of Mg-Li-Sm alloys were prepared by galvanostatic electrolysis in LiCl-KCl-MgCl2-SmCl3 melts at 670 °C.The electrolysis process and phase control of Mg-Li-Sm alloys were studied.The microstructur...Different phases of Mg-Li-Sm alloys were prepared by galvanostatic electrolysis in LiCl-KCl-MgCl2-SmCl3 melts at 670 °C.The electrolysis process and phase control of Mg-Li-Sm alloys were studied.The microstructures of α,α+β,β phases of Mg-Li-Sm alloys were characterized by X-ray diffraction(XRD) and optical microscope(OM).Analysis of scanning electron microscopy(SEM) and EDS mapping analysis showed that Mg distributed homogeneously in Mg-Li-Sm alloys.EDS result showed that the distribution of Sm was more at grain boundaries than within the grains.Inductively coupled plasma(ICP) analyses of the samples obtained by electrolysis showed that the chemical compositions of Mg-Li-Sm alloys were consistent with the phase structures of XRD patterns,and the lithium and samarium contents in Mg-Li-Sm alloys could be controlled by the electrolysis time and concentrations of SmCl3.Effect of Sm on corrosion property of Mg-12Li alloy was studied.The corrosion resistance of the alloy improved firstly and then worsened with the increase of Sm content.The optimum Sm content was about 0.7 wt.%.展开更多
Compared with solid metals,liquid metals are considered more promising cathodes for molten slat/oxide electrolysis due to their fascinating advantages,which include strong depolarization effect,strong alloying effect,...Compared with solid metals,liquid metals are considered more promising cathodes for molten slat/oxide electrolysis due to their fascinating advantages,which include strong depolarization effect,strong alloying effect,excellent selective separation,and low operating temperature.In this review,we briefly introduce the properties of the liquid metal cathodes and their selection rules,and then summarize development in liquid metal cathodes for molten salt electrolysis,specifically the extraction of Ti and separation of actinides and rare-earth metals in halide melts.We also review recent attractive progress in the preparation of liquid Ti alloys via molten oxide electrolysis by using liquid metal cathodes.Problems related to high-quality alloy production and large-scale applications are cited,and several research directions to further improve the quality of alloys are also discussed to realize the industrial applications of liquid metal cathodes.展开更多
The corrosion behavior of 316H stainless steel(SS)in the impure and purified Na Cl–KCl–Mg Cl_(2) salt was investigated at700°C.Results indicate that the main deleterious impurity induced corrosion in the impure...The corrosion behavior of 316H stainless steel(SS)in the impure and purified Na Cl–KCl–Mg Cl_(2) salt was investigated at700°C.Results indicate that the main deleterious impurity induced corrosion in the impure salt was the absorbed moisture,present in the form of Mg Cl_(2)·6H_(2)O.316H SS occurred severe intergranular corrosion with a corrosion depth of 130μm for1000 h in the impure Na Cl–KCl–Mg Cl_(2) salt.In contrast,the purification treatment of molten chloride salt by the dissolved Mg metal can remove the absorbed moisture,and the corresponding reactions were also discussed.As a result,the corrosiveness of Na Cl–KCl–Mg Cl_(2) salt is reduced significantly.316H SS occurred slight uniform corrosion with a depth of less than 5μm for 3000 h in the purified Na Cl–KCl–Mg Cl_(2) salt.展开更多
Dense zirconium coatings on copper substrates were obtained in an alumina crucible and a stainless steel crucible from FLiNaK-K_(2)ZrF_(6)molten salt at 1023 K.Due to the potential difierences between copper and zirco...Dense zirconium coatings on copper substrates were obtained in an alumina crucible and a stainless steel crucible from FLiNaK-K_(2)ZrF_(6)molten salt at 1023 K.Due to the potential difierences between copper and zirconium,zirconium can difiuse into the copper substrate to form zirconium alloys on the surface of copper substrates in the course of deposition.The coating deposited in a stainless steel crucible has a gray surface.The components of the coating are mainly CuZr2alloy and Cu_(10)Zr_(7)alloy,and,the outermost layer of the coating is a layer of amorphous pure zirconium.The coating deposited in an alumina crucible has a silvery white metallic luster.The components of the coating are mainly Cu-Zr-Al intermetallic compounds,AlCu_(2)Zr,ZrAl,AlCu and CuZr.Furthermore,two types of zirconium coatings can greatly increase the hardness of the substrate.展开更多
High entropy oxides(HEOs)with ideal element tunability and enticing entropy-driven stability have exhibited unprecedented application potential in electrochemical lithium storage.However,the general control of dimensi...High entropy oxides(HEOs)with ideal element tunability and enticing entropy-driven stability have exhibited unprecedented application potential in electrochemical lithium storage.However,the general control of dimension and morphology remains a major challenge.Here,scalable HEO morphology modulation is implemented through a salt-assisted strategy,which is achieved by regulating the solubility of reactants and the selective adsorption of salt ions on specific crystal planes.The electrochemical properties,lithiation mechanism,and structure evolution of composition-and morphology-dependent HEO anode are examined in detail.More importantly,the potential advantages of HEOs as electrode materials are evaluated from both theoretical and experimental aspects.Benefiting from the high oxygen vacancy concentration,narrow band gap,and structure durability induced by the multi-element synergy,HEO anode delivers desirable reversible capacity and reaction kinetics.In particular,Mg is evidenced to serve as a structural sustainer that significantly inhibits the volume expansion and retains the rock salt lattice.These new perspectives are expected to open a window of opportunity to compositionally/morphologi cally engineer high-performance HEO electrodes.展开更多
The properties of non-oxide materials are continuously revealed,and their applications in the fields of ceramics,energy,and catalysis are increasingly extensive.Regardless of the traditional binary materials or the MA...The properties of non-oxide materials are continuously revealed,and their applications in the fields of ceramics,energy,and catalysis are increasingly extensive.Regardless of the traditional binary materials or the MAX phases,the preparation methods,which are environmentally friendly,efficient,economical,and easy to scale-up,have always been the focus of attention.Molten salt synthesis has demonstrated unparalleled advantages in achieving non-oxide materials.In addition,with the development of the process in molten salt synthesis,it also shows great potential in scale-up production.In this review,the recent progress of molten salt synthesis in the preparation of binary non-oxide and MAX phase is reviewed,as well as some novel processes.The reaction mechanisms and the influence of synthetic conditions for certain materials are discussed in detail.The paper is finalized with the discussion of the application prospect and future research trends of molten salt synthesis in non-oxide materials.展开更多
基金the National Natural Science Foundation of China(Nos.51904286,51922003,51774027 and 51734002)the China Postdoctoral Science Foundation(No.2019M650848)。
文摘Tailings from the vanadium extraction process are discarded each year as waste,which contain approximately 30 wt%of Fe.In our previous work,we extracted Fe and Mn from vanadium slag,and Fe and Mn existed in the form of FeCl_(2) and MnCl_(2) after chlorination by NH_(4) Cl to achieve effective and green usage of waste containing Fe and Mn.In this work,square wave voltammetry(SWV)and cyclic voltammetry(CV)were applied to investigate the electrochemical behaviors of Fe^(2+)and Mn^(2+)in Na Cl-KCl melt at 800℃.The reduction processes of Fe^(2+)and Mn^(2+)were found to involve one step.The diffusion coefficients of FeCl_(2) and Mn Cl_(2) in molten salt of eutectic mixtures Na Cl-KCl molten salt were measured.The electrodeposition of Fe and Mn were performed using two electrodes at a constant cell voltage.The Mn/Fe mass ratio of the electrodeposited product in Na Cl-KCl-2.13 wt%FeCl_(2)-1.07 wt%Mn Cl_(2) was 0.0625 at 2.3 V.After the electrolysis of NaCl-KCl-2.13 wt%Fe Cl_(2)-1.07 wt%MnCl_(2) melted at 2.3 V,the electrolysis was again started under 3.0 V and the Mn/Fe mass ratio of the electrodeposited product was 36.4.This process provides a novel method to effectively separate Fe and Mn from simulated chlorinated vanadium slag.
文摘The physicochemical properties of the system, such as density, surface tension, specific conductance and melting point were measured. The results were discussed.
基金the National Nat-ural Science Foundation of China(Nos.21906019,21906018,21561002,21866004,and 21866003)the Sci-ence&Technology Support Program of Jiangxi Province,China(No.2018ACB21007)+1 种基金the Jiangxi Program of Aca-demic and Technical Leaders of Major Disciplines,China(No.20182BCB22011)the Project of the Jiangxi Provincial Department of Education,China(Nos.GJJ160550,GJJ180385,and GJJ180400).
文摘To improve the separation capacity of uranium in aqueous solutions, 3R-MoS2 nanosheets were prepared with molten salt electro- lysis and further modified with polypyrrole (PPy) to synthesize a hybrid nanoadsorbent (PPy/3R-MoS2). The preparation conditions of PPy/3R- MoS2 were investigated and the obtained nanosheets were characterized with scanning electron microscope (SEM), high resolution transmis- sion electron microscope (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectro- scopy (XPS). The results showed that PPy/3R-MoS2 exhibited enhanced adsorption capacity toward U(VI) compared to pure 3R-MoS2 and PPy;the maximum adsorption was 200.4 mg/g. The adsorption mechanism was elucidated with XPS and FTIR: (1) negatively charged PPy/3R-MoS2 nanosheets attracted by an electrostatic interaction;(2) exposed C, N, Mo, and S atoms complexed with U(VI) through co- ordination;(3) Mo in the complex partly reduced the adsorbed U(VI) to U(IV), which further regenerated the adsorption point and continu- ously adsorbed U(VI). The design of the PPy/3R-MoS2 composite with a high adsorption capacity and chemical stability provides a new direc- tion for the removal of radionuclide.
基金the financial support from the National Training Program of Innovation and Entrepreneurship for Undergraduates(201810145075)Fundamental Research Funds for the Central Universities(N172505002)+2 种基金NSFC(51704060)National Thousand Youth Talent Program of Chinathe 111 Project(B16009)
文摘Silicon(Si)and carbon(C)composites hold the promise for replacing the commercial graphite anode,thus increasing the energy density of lithium-ion batteries(LIBs).To mitigate the formation of SiC,this paper reports a molten salt electrolysis approach to prepare C-Si composite by the electrolysis of C-SiO2 composites.Unlike the conventional way of making a C coating on Si,C-SiO2 composites were prepared by pyrolyzing the low-cost sucrose and silica.The electrochemical deoxidation of the C-SiO2 composites not only produces nanostructured Si inside the C matrix but also introduces voids between the C and Si owing to the volume shrinkage from converting SiO2 to Si.More importantly,the use of Mg ion-containing molten salts precludes the generation of SiC,and the electrolytic Si@C composite anode delivers a capacity of about 1500 mAh g-1 after 100 cycles at a current density of 500 mA g-1.Further,the Si@C‖LiNi0.6Co0.2Mn0.2O2 full cell delivers a high energy density of 608 Wh kg-1.Overall,the molten salt approach provides a one-step electrochemical way to convert oxides@C to metals@C functional materials.
基金the National Natural Science Foundation of China(No.51621003)the Beijing Natural Science Foundation(No.2204073).
文摘Molten salt is an excellent medium for chemical reaction,energy transfer,and storage.Molten salt innovative technologies should be developed to recover metals from secondary resources and reserve metals from primary natural sources.Among these technologies,molten salt electrolysis is an economic and environment-friendly method to extract metals from waste materials.From the perspective of molten salt characteristics,the application of molten salts in chemistry,electrochemistry,energy,and thermal storage should be comprehensively elaborated.This review discusses further directions for the research and development of molten salt electrolysis and their use for metal recovery from various metal wastes,such as magnet scrap,nuclear waste,and cemented carbide scrap.Attention is placed on the development of various electrolysis methods for different metal containing wastes,overcoming some problems in electrolytes,electrodes,and electrolytic cells.Special focus is given to future development directions for current associated processing obstacles.
基金This work was supported by the National Natural Science Foundation of China(Nos.21976047,21790373,and 51774104)the Ph.D Student Research and Innovation Fund of the Fundamental Research Funds for the Central Universities(No.3072019GIP1011)+1 种基金University and Local Integration Development Project of Yantai,China(No.2020 XDRHXMPT36)the Sino-Russian Cooperation Fund of Harbin Engineering University(No.2021HEUCRF004).
文摘With the increasing demand of rare earth metals in functional materials,recovery of rare earth elements(REEs)from secondary resources has become important for the green economy transition.Molten salt electrolysis has the advantages of low water consumption and low hazardous waste during REE recovery.This review systematically summarizes the separation and electroextraction of REEs on various reactive electrodes in different molten salts.It also highlights the relationship between the formed alloy phases and electrodeposition parameters,including applied potential,current,and ion concentration.Moreover,the feasibility of using LiF–NaF–KF electrolyte to recover REEs is evaluated through thermodynamic analysis.Problems related to REE separation/recovery the choice of electrolyte are discussed in detail to realize the low-energy and high current efficiency of practical applications.
基金the National Natural Science Foundation of China(Grant No.51804277)supported by the State Key Laboratory of Special Rare Metal Materials(No.SKL2020K004)+1 种基金Northwest Rare Metal Materials Research Institutesupported by the State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization(No.CNMRCUKF2008)。
文摘Spent catalyst used for denitration by selective catalytic reduction(spent SCR denitration catalysts) is one of the important urban mines due to the high content of TiO_(2)(~85 wt%) and the massive accumulation amount(over 100,000 tons),therefore,value-added reutilization of titanium in spent SCR catalysts is considerably meaningful.In this paper,a novel method is proposed for converting the titanium oxide in spent SCR denitration catalysts to metallic titanium.Specifically,titanium dioxide(TiO_(2)) was firstly obtained from spent SCR denitration catalysts after removing the impurities by hydrometallurgy process.Then,TiO_(2) is converted to Ti_(2)CO by carbothermic reduction method,and Ti_(2)CO was further purified by oleic acid capture.Finally,by utilizing the as-prepared Ti_(2)CO as the consumable anode in the NaCl-KCl molten salt,high-purity metallic titanium was deposited at cathode,all confirming the feasibility for the conversion of low-grade TiO_(2) in the spent catalysts,from 60 wt% to high-purity metallic Ti(99.5 wt%), furthermore,the energy consumption of this process is 3950 kWh tonne-1 Ti,which is lower than that of most traditional titanium metallurgy methods.The method herein can provide new insights for the value-added recycling of titanium resources in urban mines.
基金Supported by the National Basic Research Program of China(2013CB632606)the National Natural Science Foundation of China(51474200)+1 种基金the Youth Innovation Promotion AssociationCAS(2015036)
文摘A novel and environmentally friendly route to directly prepare metallic vanadium from Na VO_3 by molten salt electrolysis is proposed.The feasibility about the direct electro-reduction of NaVO_3 to metallic vanadium is analyzed based on the thermodynamic calculations and experimental veri fications.The theoretical decomposition voltage of NaVO_3 to metallic vanadium is only 0.47 Vat 800°C and much lower than that of the alkali and alkali earth metal chloride salts.The value is slightly higher than that of low-valence vanadium oxides such as V_2O_3,V_3O_5 and VO.However,the low-valence vanadium oxides can be further electro-reduced to metallic vanadium thermodynamically.The thermodynamic analysis is veri fied by the experimental results.The direct preparation of metallic vanadium from NaVO_3 by molten salt electrolysis is feasible.
文摘The electrochemical behaviour of copper electrode in molten NaCl-KCl-LaCl<sub>3</sub> has been investigated.TheLa-Cu alloy is formed at first and then the metallic lanthanum is deposited when the La<sup>3+</sup>is reduced on thecopper electrode.The technological conditions of preparing La-Cu alloy by consumable cathode have been dis-cussed.The La-Cu alloy contained lanthanum over 90wt% was obtained.The composition of alloy was LaCu<sub>2</sub>and La.The current efficiency was 85% and the recovery of lanthanum was near 90%.
基金supported by the financial support from Natural Science Foundation of China(Nos.21871065,22209129 and 22071038)High-Level Innovation and Entrepreneurship(QCYRCXM-2022-123)+1 种基金support from the“Young Talent Support Plan”of Xi’an Jiaotong University(HG6J024)“Young Talent Lift Plan”of Xi’an city(095920221352).
文摘Electrocatalytic oxygen evolution reaction(OER)has been recognized as the bottleneck of overall water splitting,which is a promising approach for sustainable production of H_(2).Transition metal(TM)hydroxides are the most conventional and classical non-noble metal-based electrocatalysts for OER,while TM basic salts[M^(2+)(OH)_(2-x)(A_(m^(-))_(x/m),A=CO_(3)^(2−),NO_(3)^(−),F^(−),Cl^(−)]consisting of OH−and another anion have drawn extensive research interest due to its higher catalytic activity in the past decade.In this review,we summarize the recent advances of TM basic salts and their application in OER and further overall water splitting.We categorize TM basic salt-based OER pre-catalysts into four types(CO_(3)^(2−),NO_(3)^(−),F^(−),Cl^(−)according to the anion,which is a key factor for their outstanding performance towards OER.We highlight experimental and theoretical methods for understanding the structure evolution during OER and the effect of anion on catalytic performance.To develop bifunctional TM basic salts as catalyst for the practical electrolysis application,we also review the present strategies for enhancing its hydrogen evolution reaction activity and thereby improving its overall water splitting performance.Finally,we conclude this review with a summary and perspective about the remaining challenges and future opportunities of TM basic salts as catalysts for water electrolysis.
基金supported by the Chinese TMSR Strategic Pioneer Science and Technology Project(No.XDA02010000)Shanghai Pilot Program for Basic Research-Chinese Academy of Science,Shanghai Branch(No.JCYJ-SHFY-2021-003)the Chinese Academy of Sciences Special Research Assistant Funding Project.
文摘In a thorium-based molten salt reactor(TMSR),it is difficult to achieve the pure 232Th–^(233)U fuel cycle without sufficient^(233)U fuel supply.Therefore,the original molten salt reactor was designed to use enriched uranium or plutonium as the starting fuel.By exploiting plutonium as the starting fuel and thorium as the fertile fuel,the high-purity^(233)U produced can be separated from the spent fuel by fluorination volatilization.Therefore,the molten salt reactor started with plutonium can be designed as a^(233)U breeder with the burning plutonium extracted from a pressurized water reactor(PWR).Combining these advantages,the study of the physical properties of plutonium-activated salt reactors is attractive.This study mainly focused on the burnup performance and temperature reactivity coefficient of a small modular molten-salt reactor started with plutonium(SM-MSR-Pu).The neutron spectra,^(233)U production,plutonium incineration,minor actinide(MA)residues,and temperature reactivity coefficients for different fuel salt volume fractions(VF)and hexagon pitch(P)sizes were calculated to analyze the burnup behavior in the SM-SMR-Pu.Based on the comparative analysis results of the burn-up calculation,a lower VF and larger P size are more beneficial for improving the burnup performance.However,from a passive safety perspective,a higher fuel volume fraction and smaller hexagon pitch size are necessary to achieve a deep negative feedback coefficient.Therefore,an excellent burnup performance and a deep negative temperature feedback coefficient are incompatible,and the optimal design range is relatively narrow in the optimized design of an SM-MSR-Pu.In a comprehensive consideration,P=20 cm and VF=20%are considered to be relatively balanced design parameters.Based on the fuel off-line batching scheme,a 250 MWth SM-MSR-Pu can produce approximately 29.83 kg of ^(233)U,incinerate 98.29 kg of plutonium,and accumulate 14.70 kg of MAs per year,and the temperature reactivity coefficient can always be lower than−4.0pcm/K.
基金Project supported by the National Natural Science Foundation of China (5076403)
文摘Electrodeposition of magnesium-yttrium alloys from molten salts was studied by electrochemical techniques.LiF-YF3 was electrolyte system with magnesium oxide and Yttrium oxide as raw materials.It was proved that Mg2+ and Y3+was deposited more prior than other ions during cyclic voltammetry and potential step measurement at 1050 °C.Voltammograms showed Mg2+ could be deposited at-0.5 V,and Y3+ could be deposited at-0.7 V on tungsten electrode compared with platinum electrode.The sedimentation of Mg2+ was more positive about 230 mV than that of other ions in electrolyte.The electrolytic codeposition of yttrium and magnesium was 0.58 V on condition that the weight ratio of Y2O3/MgO was 4:1.Chronopotentiogram indicated that the process of electrodeposition of magnesium-yttrium alloys on tungsten electrode was controlled by diffusion of ions from electrolyte to electrode interface.It was feasible to prepare Magnesium-Yttrium alloys by controlling content of ions in molten salt electrolyte.
基金supported by 863 project of Ministry of Science and Technology of China (2006AA03Z510)the National Natural Science Foundation of China (50871033)
文摘Different phases of Mg-Li-Sm alloys were prepared by galvanostatic electrolysis in LiCl-KCl-MgCl2-SmCl3 melts at 670 °C.The electrolysis process and phase control of Mg-Li-Sm alloys were studied.The microstructures of α,α+β,β phases of Mg-Li-Sm alloys were characterized by X-ray diffraction(XRD) and optical microscope(OM).Analysis of scanning electron microscopy(SEM) and EDS mapping analysis showed that Mg distributed homogeneously in Mg-Li-Sm alloys.EDS result showed that the distribution of Sm was more at grain boundaries than within the grains.Inductively coupled plasma(ICP) analyses of the samples obtained by electrolysis showed that the chemical compositions of Mg-Li-Sm alloys were consistent with the phase structures of XRD patterns,and the lithium and samarium contents in Mg-Li-Sm alloys could be controlled by the electrolysis time and concentrations of SmCl3.Effect of Sm on corrosion property of Mg-12Li alloy was studied.The corrosion resistance of the alloy improved firstly and then worsened with the increase of Sm content.The optimum Sm content was about 0.7 wt.%.
基金the National Natural Science Foundation of China(Nos.51725401 and 51904030)the Fundamental Research Funds for the Cental Universities(No.FRF-TP-18-003C2).
文摘Compared with solid metals,liquid metals are considered more promising cathodes for molten slat/oxide electrolysis due to their fascinating advantages,which include strong depolarization effect,strong alloying effect,excellent selective separation,and low operating temperature.In this review,we briefly introduce the properties of the liquid metal cathodes and their selection rules,and then summarize development in liquid metal cathodes for molten salt electrolysis,specifically the extraction of Ti and separation of actinides and rare-earth metals in halide melts.We also review recent attractive progress in the preparation of liquid Ti alloys via molten oxide electrolysis by using liquid metal cathodes.Problems related to high-quality alloy production and large-scale applications are cited,and several research directions to further improve the quality of alloys are also discussed to realize the industrial applications of liquid metal cathodes.
基金supported by the National Science Foundation of Shanghai(No.22ZR1474600)the National Natural Science Foundation of China(No.12175302)+1 种基金the“Thorium Molten Salt Reactor Nuclear Energy System”Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA 02040000)the“Transformational Technologies for Clean Energy and Demonstration,”Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA 21000000)。
文摘The corrosion behavior of 316H stainless steel(SS)in the impure and purified Na Cl–KCl–Mg Cl_(2) salt was investigated at700°C.Results indicate that the main deleterious impurity induced corrosion in the impure salt was the absorbed moisture,present in the form of Mg Cl_(2)·6H_(2)O.316H SS occurred severe intergranular corrosion with a corrosion depth of 130μm for1000 h in the impure Na Cl–KCl–Mg Cl_(2) salt.In contrast,the purification treatment of molten chloride salt by the dissolved Mg metal can remove the absorbed moisture,and the corresponding reactions were also discussed.As a result,the corrosiveness of Na Cl–KCl–Mg Cl_(2) salt is reduced significantly.316H SS occurred slight uniform corrosion with a depth of less than 5μm for 3000 h in the purified Na Cl–KCl–Mg Cl_(2) salt.
基金Funded by National MCF Energy R&D Program(No.2019YFE03130002)。
文摘Dense zirconium coatings on copper substrates were obtained in an alumina crucible and a stainless steel crucible from FLiNaK-K_(2)ZrF_(6)molten salt at 1023 K.Due to the potential difierences between copper and zirconium,zirconium can difiuse into the copper substrate to form zirconium alloys on the surface of copper substrates in the course of deposition.The coating deposited in a stainless steel crucible has a gray surface.The components of the coating are mainly CuZr2alloy and Cu_(10)Zr_(7)alloy,and,the outermost layer of the coating is a layer of amorphous pure zirconium.The coating deposited in an alumina crucible has a silvery white metallic luster.The components of the coating are mainly Cu-Zr-Al intermetallic compounds,AlCu_(2)Zr,ZrAl,AlCu and CuZr.Furthermore,two types of zirconium coatings can greatly increase the hardness of the substrate.
基金supported by the National Natural Science Foundation of China(52104309,52272021)the Natural Science Foundation of Hubei Province(2021CFB010)。
文摘High entropy oxides(HEOs)with ideal element tunability and enticing entropy-driven stability have exhibited unprecedented application potential in electrochemical lithium storage.However,the general control of dimension and morphology remains a major challenge.Here,scalable HEO morphology modulation is implemented through a salt-assisted strategy,which is achieved by regulating the solubility of reactants and the selective adsorption of salt ions on specific crystal planes.The electrochemical properties,lithiation mechanism,and structure evolution of composition-and morphology-dependent HEO anode are examined in detail.More importantly,the potential advantages of HEOs as electrode materials are evaluated from both theoretical and experimental aspects.Benefiting from the high oxygen vacancy concentration,narrow band gap,and structure durability induced by the multi-element synergy,HEO anode delivers desirable reversible capacity and reaction kinetics.In particular,Mg is evidenced to serve as a structural sustainer that significantly inhibits the volume expansion and retains the rock salt lattice.These new perspectives are expected to open a window of opportunity to compositionally/morphologi cally engineer high-performance HEO electrodes.
基金the National Natural Science Foundation of China(Grant No.51804277)supported by the State Key Laboratory of Special Rare Metal Materials(No.SKL2020K004)Northwest Rare Metal Materials Research Institute.
文摘The properties of non-oxide materials are continuously revealed,and their applications in the fields of ceramics,energy,and catalysis are increasingly extensive.Regardless of the traditional binary materials or the MAX phases,the preparation methods,which are environmentally friendly,efficient,economical,and easy to scale-up,have always been the focus of attention.Molten salt synthesis has demonstrated unparalleled advantages in achieving non-oxide materials.In addition,with the development of the process in molten salt synthesis,it also shows great potential in scale-up production.In this review,the recent progress of molten salt synthesis in the preparation of binary non-oxide and MAX phase is reviewed,as well as some novel processes.The reaction mechanisms and the influence of synthetic conditions for certain materials are discussed in detail.The paper is finalized with the discussion of the application prospect and future research trends of molten salt synthesis in non-oxide materials.
