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 oxygen-ion conductor, the reducing agent, and the molten oxide slag containing electroactive matter were used as constituent of a galvanic cell. Metal was directly electroreduced from molten slag using a short-cir...The oxygen-ion conductor, the reducing agent, and the molten oxide slag containing electroactive matter were used as constituent of a galvanic cell. Metal was directly electroreduced from molten slag using a short-circuit galvanic cell. The following galvanic cell was assembled in the present experiment： graphite rod, [-O]Fe-C saturated ｜ZrO2 （MgO） ｜ Cu（1） ＋ （FeO）（slag） , and molybdenum wire. The FeO electroreduction reaction was studied through measuring short circuit current by controlling factors such as temperature, the FeO content in molten slags, and the external circuit resistance. An overall kinetics model was developed to describe the process of FeO electroreductiono It was found that the modeled curves were in good agreement with the experimental values. The new oxide reduction method in the metallurgy with controlled oxygen flow was proposed and the metallurgical theory with controlled oxygen flow was developed.展开更多
A thermodynamic model has been built up for the interactions between molten Ti alloys and oxide molding materials in the way of decomposition and solution of molding materials, then the influences on the reaction free...A thermodynamic model has been built up for the interactions between molten Ti alloys and oxide molding materials in the way of decomposition and solution of molding materials, then the influences on the reaction free energy changes have been calculated and discussed.展开更多
The high-temperature requirement for liquid iron smelting via molten oxide electrolysis presents significant challenges.This study investigates the electrochemical reduction of Fe(Ⅲ)in a novel low-temperature electro...The high-temperature requirement for liquid iron smelting via molten oxide electrolysis presents significant challenges.This study investigates the electrochemical reduction of Fe(Ⅲ)in a novel low-temperature electrolyte,Na_(2)SiO_(3)-SiO_(2)-Fe_(2)O_(3),utilizing cyclic voltammetry and square wave voltammetry techniques.The results show that Fe(Ⅲ)reduction occurs in two steps:Fe(Ⅲ)+e^(−)→Fe(Ⅱ),Fe(Ⅱ)+2e^(−)→Fe,and that the redox process of Fe(Ⅲ)/Fe(Ⅱ)at the tungsten electrode is an irreversible reaction controlled by diffusion.The diffusion coefficients of Fe(Ⅲ)in the molten Na_(2)SiO_(3)-SiO_(2)-Fe_(2)O_(3)in the temperature range of 1248–1278 K are between 1.86×10^(−6)cm^(2)/s and 1.58×10^(−4)cm^(2)/s.The diffusion activation energy of Fe(Ⅲ)in the molten salt is 1825.41 kJ/mol.As confirmed by XRD analysis,potentiostatic electrolysis at−0.857 V(vs.O_(2)/O_(complex)^(2-))for 6 h produces metallic iron on the cathode.展开更多
The mechanism of the electrolytic codeposition of Y Al alloy in molten LiF AlF 3 Al 2O 3 YF 3, LiF YF 3 Y 2O 3 AlF 3 and LiF YF 3 Y 2O 3 Al 2O 3 systems was investigated by means of cyclic volta...The mechanism of the electrolytic codeposition of Y Al alloy in molten LiF AlF 3 Al 2O 3 YF 3, LiF YF 3 Y 2O 3 AlF 3 and LiF YF 3 Y 2O 3 Al 2O 3 systems was investigated by means of cyclic voltammetry. The electrodeposited products were analysed by X ray diffraction. The results show that the electrolytic codeposition of Y Al alloy in the LiF YF 3 Y 2O 3 Al 2O 3 system without AlF 3 can be achieved at the same potential for Y(Ⅲ) and Al(Ⅲ) which have great difference in deposition potential. It is beneficial to codeposition of Y(Ⅲ) and Al(Ⅲ) when temperature rises. The potential of beginning codeposition is about -0.85 V ( vs Pt reference electrode), but only at the potential of -0.95 V or more negative can Y based Al alloy containing a great amount of yttrium be obtained.展开更多
Despite its existence for more than 80 years,the titanium industry is still challenged by massive carbon emissions,high production costs,and large resource waste.More than one hundred million tons of Ti-bearing blast ...Despite its existence for more than 80 years,the titanium industry is still challenged by massive carbon emissions,high production costs,and large resource waste.More than one hundred million tons of Ti-bearing blast furnace slag(TB-slag)has been discarded in China because of the difficulty of reutilization,which requires efficient titanium extraction and recovery technologies.This paper describes a low-cost,carbon-emission-free method for Ti extraction and oxygen evolution via molten oxide electrolysis(MOE)vacuum distillation.After a comprehensive analysis of the binding energies and activities of liquid metals,the highlights of our study are as follows.1)Sb has the best preferential deposition of Ti among a series of high-Ti-affinitive liquid metal cathodes(Cu,Ni,Pb,Sn,and Sb).2)The Ir anode was first used in TB-slag with IrO_(2) formed on its surface to protect it from further corrosion.3)An alloy containing Ti and Ca can be obtained by MOE,and Ti and Ca metals can be refined by further vacuum distillation.4)A closed loop is formed in the overall process owing to the recyclable Sb cathode and continuous feeding of TB-slag into the electrolyte.This simple,low-cost,and environmentally friendly method can realize the efficient utilization of Ti resources and achieve carbon neutrality.展开更多
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Item Sponsored by National Natural Science Foundation of China (50274008 ,50574011) Provincial Natural Science Foundationof Hubei Province of China (2005ABA019)
文摘The oxygen-ion conductor, the reducing agent, and the molten oxide slag containing electroactive matter were used as constituent of a galvanic cell. Metal was directly electroreduced from molten slag using a short-circuit galvanic cell. The following galvanic cell was assembled in the present experiment： graphite rod, [-O]Fe-C saturated ｜ZrO2 （MgO） ｜ Cu（1） ＋ （FeO）（slag） , and molybdenum wire. The FeO electroreduction reaction was studied through measuring short circuit current by controlling factors such as temperature, the FeO content in molten slags, and the external circuit resistance. An overall kinetics model was developed to describe the process of FeO electroreductiono It was found that the modeled curves were in good agreement with the experimental values. The new oxide reduction method in the metallurgy with controlled oxygen flow was proposed and the metallurgical theory with controlled oxygen flow was developed.
基金This work was supported by Postdoctoral Foundation of Northwestern Polytechnical University and Science Research FOundation o
文摘A thermodynamic model has been built up for the interactions between molten Ti alloys and oxide molding materials in the way of decomposition and solution of molding materials, then the influences on the reaction free energy changes have been calculated and discussed.
基金Project(52074084)supported by the National Natural Science Foundation of China。
文摘The high-temperature requirement for liquid iron smelting via molten oxide electrolysis presents significant challenges.This study investigates the electrochemical reduction of Fe(Ⅲ)in a novel low-temperature electrolyte,Na_(2)SiO_(3)-SiO_(2)-Fe_(2)O_(3),utilizing cyclic voltammetry and square wave voltammetry techniques.The results show that Fe(Ⅲ)reduction occurs in two steps:Fe(Ⅲ)+e^(−)→Fe(Ⅱ),Fe(Ⅱ)+2e^(−)→Fe,and that the redox process of Fe(Ⅲ)/Fe(Ⅱ)at the tungsten electrode is an irreversible reaction controlled by diffusion.The diffusion coefficients of Fe(Ⅲ)in the molten Na_(2)SiO_(3)-SiO_(2)-Fe_(2)O_(3)in the temperature range of 1248–1278 K are between 1.86×10^(−6)cm^(2)/s and 1.58×10^(−4)cm^(2)/s.The diffusion activation energy of Fe(Ⅲ)in the molten salt is 1825.41 kJ/mol.As confirmed by XRD analysis,potentiostatic electrolysis at−0.857 V(vs.O_(2)/O_(complex)^(2-))for 6 h produces metallic iron on the cathode.
文摘The mechanism of the electrolytic codeposition of Y Al alloy in molten LiF AlF 3 Al 2O 3 YF 3, LiF YF 3 Y 2O 3 AlF 3 and LiF YF 3 Y 2O 3 Al 2O 3 systems was investigated by means of cyclic voltammetry. The electrodeposited products were analysed by X ray diffraction. The results show that the electrolytic codeposition of Y Al alloy in the LiF YF 3 Y 2O 3 Al 2O 3 system without AlF 3 can be achieved at the same potential for Y(Ⅲ) and Al(Ⅲ) which have great difference in deposition potential. It is beneficial to codeposition of Y(Ⅲ) and Al(Ⅲ) when temperature rises. The potential of beginning codeposition is about -0.85 V ( vs Pt reference electrode), but only at the potential of -0.95 V or more negative can Y based Al alloy containing a great amount of yttrium be obtained.
基金This work has been supported by National Natural Science Foundation of China(51725401).
文摘Despite its existence for more than 80 years,the titanium industry is still challenged by massive carbon emissions,high production costs,and large resource waste.More than one hundred million tons of Ti-bearing blast furnace slag(TB-slag)has been discarded in China because of the difficulty of reutilization,which requires efficient titanium extraction and recovery technologies.This paper describes a low-cost,carbon-emission-free method for Ti extraction and oxygen evolution via molten oxide electrolysis(MOE)vacuum distillation.After a comprehensive analysis of the binding energies and activities of liquid metals,the highlights of our study are as follows.1)Sb has the best preferential deposition of Ti among a series of high-Ti-affinitive liquid metal cathodes(Cu,Ni,Pb,Sn,and Sb).2)The Ir anode was first used in TB-slag with IrO_(2) formed on its surface to protect it from further corrosion.3)An alloy containing Ti and Ca can be obtained by MOE,and Ti and Ca metals can be refined by further vacuum distillation.4)A closed loop is formed in the overall process owing to the recyclable Sb cathode and continuous feeding of TB-slag into the electrolyte.This simple,low-cost,and environmentally friendly method can realize the efficient utilization of Ti resources and achieve carbon neutrality.
