The current study focuses on the electrolyte penetration of the graphite cathode in a NaF−KF−LiF−AlF_(3) aluminum-electrolysis system with a cryolite ratio of 1.3.It involves a comprehensive investigation of the elect...The current study focuses on the electrolyte penetration of the graphite cathode in a NaF−KF−LiF−AlF_(3) aluminum-electrolysis system with a cryolite ratio of 1.3.It involves a comprehensive investigation of the electrolyte in the cathode before and after electrolysis by X-ray diffraction and analysis of the results by semi-quantitative calculation in MAUD.The results show that KF can promote electrolyte penetration,with higher KF contents resulting in greater penetration.During electrolyte penetration,K_(2)NaAlF_(6) and solid solutions containing KF play important roles in KF-containing systems.LiF effectively prevents the electrolyte penetration,while the Na_(3)Li_(3)Al_(2)F_(12) phase plays an essential role in systems with high LiF contents.展开更多
A new process of producing magnesium by thermal vacuum reduction using dolomite and magnesite as materials and silicocalcium as reductant was studied in this study. The reduction process of MgO by silicocalcium was an...A new process of producing magnesium by thermal vacuum reduction using dolomite and magnesite as materials and silicocalcium as reductant was studied in this study. The reduction process of MgO by silicocalcium was analyzed by phases analysis of reduction slag through X-ray diffraction （XRD） and the factors influencing the reduction ratio of MgO were investigated. The experi- mental results show that when using silicocalcium as reductant, the reduction ratio of MgO can be over 93 %. In the reduction process, calcium in silicocalcium takes part in the reduction reaction of MgO firstly below 1,000 ℃ and it makes CaSi2 decompose. It also releases elemental silicon which has more reactive activity and improves the reduction reaction of MgO. That is the main cause that the reduction ratio of MgO using silicocalcium as reductant is 8 %-10 % higher than that by Pidgeon process using fer- rosilicon as reductant under the same conditions.展开更多
To investigate the electrodeposition mechanism of Ti^4＋, electrochemistry experiments were conducted using a KF-KCl-K2Ti6O13 molten salt at a Cu electrode at 950 ℃. Transient electrochemical techniques such as cycli...To investigate the electrodeposition mechanism of Ti^4＋, electrochemistry experiments were conducted using a KF-KCl-K2Ti6O13 molten salt at a Cu electrode at 950 ℃. Transient electrochemical techniques such as cyclic voltammetry（CV） and square-wave voltammetry were used in this study. The main phases and compositions of the product were analyzed by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, and energy-dispersive spectrometry（EDS）. The resulting product has the structure of metallic Ti. The results indicate that Ti^4＋ is reduced to metallic Ti by a two-step mechanism, corresponding to the reduction pathway： Ti^4＋→ Ti^2＋→ Ti. Moreover, Cu-Ti alloy could be obtained by the potentiostatic electrolysis at a Cu electrode.展开更多
基金supported by the National Key Research and Development Program of China(No.2021YFC29003205)the National Natural Science Foundation of China(Nos.21878045,51504058)+1 种基金the Fundamental Research Funds for the Central Universities,China(No.N2225019)Natural Science Foundation of Liaoning Province,China(No.2022-MS-106)。
基金financial supports from the National Natural Science Foundation of China (Nos.51774080,22078056)the National Key R&D Program of China (No.2018YFC1901905)。
文摘The current study focuses on the electrolyte penetration of the graphite cathode in a NaF−KF−LiF−AlF_(3) aluminum-electrolysis system with a cryolite ratio of 1.3.It involves a comprehensive investigation of the electrolyte in the cathode before and after electrolysis by X-ray diffraction and analysis of the results by semi-quantitative calculation in MAUD.The results show that KF can promote electrolyte penetration,with higher KF contents resulting in greater penetration.During electrolyte penetration,K_(2)NaAlF_(6) and solid solutions containing KF play important roles in KF-containing systems.LiF effectively prevents the electrolyte penetration,while the Na_(3)Li_(3)Al_(2)F_(12) phase plays an essential role in systems with high LiF contents.
基金financially supported by the Industrial Research Project of Liaoning Province(No.2011221002)the Project of High Technology Plan of Magnesium Materials of Liaoning(No.MYF2011-34)
文摘A new process of producing magnesium by thermal vacuum reduction using dolomite and magnesite as materials and silicocalcium as reductant was studied in this study. The reduction process of MgO by silicocalcium was analyzed by phases analysis of reduction slag through X-ray diffraction （XRD） and the factors influencing the reduction ratio of MgO were investigated. The experi- mental results show that when using silicocalcium as reductant, the reduction ratio of MgO can be over 93 %. In the reduction process, calcium in silicocalcium takes part in the reduction reaction of MgO firstly below 1,000 ℃ and it makes CaSi2 decompose. It also releases elemental silicon which has more reactive activity and improves the reduction reaction of MgO. That is the main cause that the reduction ratio of MgO using silicocalcium as reductant is 8 %-10 % higher than that by Pidgeon process using fer- rosilicon as reductant under the same conditions.
基金financially supported by the State Key Development Program for Basic Research of China (973 Program, Grant No.2013CB632606-1)
文摘To investigate the electrodeposition mechanism of Ti^4＋, electrochemistry experiments were conducted using a KF-KCl-K2Ti6O13 molten salt at a Cu electrode at 950 ℃. Transient electrochemical techniques such as cyclic voltammetry（CV） and square-wave voltammetry were used in this study. The main phases and compositions of the product were analyzed by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, and energy-dispersive spectrometry（EDS）. The resulting product has the structure of metallic Ti. The results indicate that Ti^4＋ is reduced to metallic Ti by a two-step mechanism, corresponding to the reduction pathway： Ti^4＋→ Ti^2＋→ Ti. Moreover, Cu-Ti alloy could be obtained by the potentiostatic electrolysis at a Cu electrode.
