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M. F. Simpson - One of the best experts on this subject based on the ideXlab platform.
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Electrolytic Reduction of spent light water reactor fuel bench scale experiment results
Journal of Nuclear Science and Technology, 2007Co-Authors: S. D. Herrmann, M. F. SimpsonAbstract:A series of experiments were performed to demonstrate the Electrolytic Reduction of spent light water reactor fuel at bench-scale in a hot cell at the Idaho National Laboratory Materials and Fuels Complex. The process involves the conversion of oxide fuel to metal by Electrolytic means, which would then enable subsequent separation and recovery of actinides via existing electrometallurgical technologies, i.e., electrorefining. Four Electrolytic Reduction runs were performed at bench scale using ∼500 ml of molten LiCl–1 wt% Li2O electrolyte at 650°C. In each run, ∼50 g of crushed spent oxide fuel was loaded into a permeable stainless steel basket and immersed into the electrolyte as the cathode. A spiral wound platinumwire was immersed into the electrolyte as the anode. When a controlled electric current was conducted through the anode and cathode, the oxide fuel was reduced to metal in the basket and oxygen gas was evolved at the anode. Salt samples were extracted before and after each Electrolytic reduct...
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Electrolytic Reduction of Spent Light Water Reactor Fuel Bench-Scale Experiment Results
Journal of Nuclear Science and Technology, 2007Co-Authors: S. D. Herrmann, M. F. SimpsonAbstract:A series of experiments were performed to demonstrate the Electrolytic Reduction of spent light water reactor fuel at bench-scale in a hot cell at the Idaho National Laboratory Materials and Fuels Complex. The process involves the conversion of oxide fuel to metal by Electrolytic means, which would then enable subsequent separation and recovery of actinides via existing electrometallurgical technologies, i.e., electrorefining. Four Electrolytic Reduction runs were performed at bench scale using ~500 ml of molten LiCl – 1 wt% Li2O electrolyte at 650 oC. In each run, ~50 g of crushed spent oxide fuel was loaded into a permeable stainless steel basket and immersed into the electrolyte as the cathode. A spiral wound platinum wire was immersed into the electrolyte as the anode. When a controlled electric current was conducted through the anode and cathode, the oxide fuel was reduced to metal in the basket and oxygen gas was evolved at the anode. Salt samples were extracted before and after each Electrolytic Reduction run and analyzed for fuel and fission product constituents. The fuel baskets following each run were sectioned and the fuel was sampled, revealing an extent of uranium oxide Reduction in excess of 98%.
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Electrolytic Reduction of spent oxide fuel bench scale test results
Global 2005 Tsukuba Japan 10 09 2005 10 13 2005, 2005Co-Authors: S. D. Herrmann, M. F. SimpsonAbstract:A series of tests were performed to demonstrate the Electrolytic Reduction of spent light water reactor fuel at bench-scale in a hot cell at the Idaho National Laboratory Materials and Fuels Complex (formerly Argonne National Laboratory - West). The process involves the conversion of oxide fuel to metal by Electrolytic means, which would then enable subsequent separation and recovery of actinides via existing electrometallurgical technologies, i.e., electrorefining. Four Electrolytic Reduction runs were performed at bench scale using ~500 ml of molten LiCl -- 1 wt% Li2O electrolyte at 650 oC. In each run, ~50 g of crushed spent oxide fuel was loaded into a permeable stainless steel basket and immersed into the electrolyte as the cathode. A spiral wound platinum wire was immersed into the electrolyte as the anode. When a controlled electric current was conducted through the anode and cathode, the oxide fuel was reduced to metal in the basket and oxygen gas was evolved at the anode. Salt samples were extracted before and after each Electrolytic Reduction run and analyzed for fuel and fission product constituents. The fuel baskets following each run were sectioned and sampled, revealing an extent of uranium oxide Reduction in excess of 98%.
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Electrolytic Reduction of spent oxide fuel -- bench-scale test preparations.
2002Co-Authors: S. D. Herrmann, M. F. Simpson, D. R. WahlquistAbstract:Preparations are underway to demonstrate the Electrolytic Reduction of spent oxide nuclear fuel in the Hot Fuel Examination Facility (HFEF) and Argonne National Laboratory--West (ANL-W). The Electrolytic Reduction process, developed by the Laboratory's Chemical Technology Division, operates in an electrochemical cell that uses a molten solution of lithium chloride and dissolved lithium oxide as the electrolyte. The spent oxide fuel is loaded into a permeable steel basket as the cathode in the electrochemical cell and a platinum electrode functions as the anode. When an electrical potential is applied, the uranium oxide and other metal oxides are reduced to metal and remain in the cathode basket. Oxygen gas is formed at the platinum anode and dissipates into the system's argon atmosphere. Once reduced to metal, the spent fuel is capable of further electrometallurgical treatment in an electrorefiner to recover uranium and to ultimately effect the disposition of fission products into ceramic and metal waste forms. Thus, the Electrolytic Reduction process expands the electrometallurgical treatment capability to include spent oxide fuel. This report describes the bench-scale test preparations that are underway to demonstrate the Electrolytic Reduction of spent oxide fuel.
S. D. Herrmann - One of the best experts on this subject based on the ideXlab platform.
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separation and recovery of uranium metal from spent light water reactor fuel via Electrolytic Reduction and electrorefining
Nuclear Technology, 2010Co-Authors: S. D. Herrmann, Shelly X LiAbstract:A series of bench-scale experiments was performed in a hot cell at Idaho National Laboratory to demonstrate the separation and recovery of uranium metal from spent light water reactor (LWR) fuel. The experiments involved crushing spent LWR fuel to particulate and separating it from its cladding. Oxide fuel particulate was then converted to metal in a series of six Electrolytic Reduction runs performed in succession with a single salt loading of molten LiCl-1 wt% Li 2 O at 650°C. Analysis of salt samples following the series of Electrolytic Reduction runs identified the partitioning of select fission products from the spent fuel to the molten salt electrolyte. The extent of metal oxide conversion in the posttest fuel was also quantified, including a 99.7% conversion of uranium oxide to metal. Uranium metal was then separated from the reduced LWR fuel in a series of six electrorefining runs performed in succession with a single salt loading of molten LiCl-KCl-UCl 3 at 500°C. Analysis of salt samples following the series of electrorefining runs identified additional partitioning of fission products into the molten salt electrolyte. Analyses of the separated uranium metal were performed, and its decontamination factors were determined.
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Observations of Oxygen Ion Behavior in the Lithium-Based Electrolytic Reduction of Uranium Oxide
2009Co-Authors: S. D. Herrmann, Brenda E. Serrano-rodriguezAbstract:Parametric studies were performed on a lithium-based Electrolytic Reduction process at bench-scale to investigate the behavior of oxygen ions in the Reduction of uranium oxide for various electrochemical cell configurations. Specifically, a series of eight Electrolytic Reduction runs was performed in a common salt bath of LiCl – 1 wt% Li2O. The variable parameters included fuel basket containment material (i.e., stainless steel wire mesh and sintered stainless steel) and applied electrical charge (i.e., 75 – 150% of the theoretical charge for complete Reduction of uranium oxide in a basket to uranium metal). Samples of the molten salt electrolyte were taken at regular intervals throughout each run and analyzed to produce a time plot of Li2O concentrations in the bulk salt over the course of the runs. Following each run, the fuel basket was sectioned and the fuel was removed. Samples of the fuel were analyzed for the extent of uranium oxide Reduction to metal and for the concentration of salt constituents, i.e., LiCl and Li2O. Extents of uranium oxide Reduction ranged from 43 – 70% in stainless steel wire mesh baskets and 8 – 33 % in sintered stainless steel baskets. The concentrations of Li2O in the salt phase ofmore » the fuel product from the stainless steel wire mesh baskets ranged from 6.2 – 9.2 wt%, while those for the sintered stainless steel baskets ranged from 26 – 46 wt%. Another series of tests was performed to investigate the dissolution of Li2O in LiCl at 650 °C across various cathode containment materials (i.e., stainless steel wire mesh, sintered stainless steel and porous magnesia) and configurations (i.e., stationary and rotating cylindrical baskets). Dissolution of identical loadings of Li2O particulate reached equilibrium within one hour for stationary stainless steel wire mesh baskets, while the same took several hours for sintered stainless steel and porous magnesia baskets. Rotation of an annular cylindrical basket of stainless steel wire mesh accelerated the Li2O dissolution rate by more than a factor of six.« less
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Electrolytic Reduction of Spent Nuclear Oxide Fuel -- Effects of Fuel Form and Cathode Containment Materials on Bench-Scale Operations
2007Co-Authors: S. D. HerrmannAbstract:A collaborative effort between the Idaho National Laboratory (INL) and Korea Atomic Energy Research Institute (KAERI) is underway per an International Nuclear Energy Research Initiative to advance the development of a pyrochemical process for the treatment of spent nuclear oxide fuel. To assess the effects of specific process parameters that differ between oxide Reduction operations at INL and KAERI, a series of 4 Electrolytic Reduction runs will be performed with a single salt loading of LiCl-Li2O at 650 °C using a test apparatus located inside of a hot cell at INL. The spent oxide fuel for the tests will be irradiated UO2 that has been subjected to a voloxidation process to form U3O8. The primary variables in the 4 Electrolytic Reduction runs will be fuel basket containment material and Li2O concentration in the LiCl salt. All 4 runs will be performed with comparable fuel loadings (approximately 50 g) and fuel compositions and will utilize a platinum anode and a Ni/NiO reference electrode. The first 2 runs will elucidate the effect of fuel form on the Electrolytic Reduction process by comparison of the above test results with U3O8 versus results from previous tests with UO2. The first 3 runs will investigatemore » the impact that the cathode containment material has on the Electrolytic Reduction of spent oxide fuel. The 3rd and 4th runs will investigate the effect of Li2O concentration on the Reduction process with a porous MgO cathode containment.« less
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Electrolytic Reduction of spent light water reactor fuel bench scale experiment results
Journal of Nuclear Science and Technology, 2007Co-Authors: S. D. Herrmann, M. F. SimpsonAbstract:A series of experiments were performed to demonstrate the Electrolytic Reduction of spent light water reactor fuel at bench-scale in a hot cell at the Idaho National Laboratory Materials and Fuels Complex. The process involves the conversion of oxide fuel to metal by Electrolytic means, which would then enable subsequent separation and recovery of actinides via existing electrometallurgical technologies, i.e., electrorefining. Four Electrolytic Reduction runs were performed at bench scale using ∼500 ml of molten LiCl–1 wt% Li2O electrolyte at 650°C. In each run, ∼50 g of crushed spent oxide fuel was loaded into a permeable stainless steel basket and immersed into the electrolyte as the cathode. A spiral wound platinumwire was immersed into the electrolyte as the anode. When a controlled electric current was conducted through the anode and cathode, the oxide fuel was reduced to metal in the basket and oxygen gas was evolved at the anode. Salt samples were extracted before and after each Electrolytic reduct...
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Electrolytic Reduction of Spent Light Water Reactor Fuel Bench-Scale Experiment Results
Journal of Nuclear Science and Technology, 2007Co-Authors: S. D. Herrmann, M. F. SimpsonAbstract:A series of experiments were performed to demonstrate the Electrolytic Reduction of spent light water reactor fuel at bench-scale in a hot cell at the Idaho National Laboratory Materials and Fuels Complex. The process involves the conversion of oxide fuel to metal by Electrolytic means, which would then enable subsequent separation and recovery of actinides via existing electrometallurgical technologies, i.e., electrorefining. Four Electrolytic Reduction runs were performed at bench scale using ~500 ml of molten LiCl – 1 wt% Li2O electrolyte at 650 oC. In each run, ~50 g of crushed spent oxide fuel was loaded into a permeable stainless steel basket and immersed into the electrolyte as the cathode. A spiral wound platinum wire was immersed into the electrolyte as the anode. When a controlled electric current was conducted through the anode and cathode, the oxide fuel was reduced to metal in the basket and oxygen gas was evolved at the anode. Salt samples were extracted before and after each Electrolytic Reduction run and analyzed for fuel and fission product constituents. The fuel baskets following each run were sectioned and the fuel was sampled, revealing an extent of uranium oxide Reduction in excess of 98%.
Jin-mok Hur - One of the best experts on this subject based on the ideXlab platform.
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Quantitative Analysis of Oxygen Gas Exhausted from Anode through In Situ Measurement during Electrolytic Reduction
Science and Technology of Nuclear Installations, 2017Co-Authors: Eun-young Choi, Jeong Lee, Dong Hyun Heo, Jin-mok HurAbstract:Quantitative analysis by in situ measurement of oxygen gas evolved from an anode was employed to monitor the progress of Electrolytic Reduction of simulated oxide fuel in a molten Li2O–LiCl salt. The Electrolytic Reduction of 0.6 kg of simulated oxide fuel was performed in 5 kg of 1.5 wt.% Li2O–LiCl molten salt at 650°C. Porous cylindrical pellets of simulated oxide fuel were used as the cathode by loading a stainless steel wire mesh cathode basket. A platinum plate was employed as the anode. The oxygen gas evolved from the anode was exhausted to the instrumentation for in situ measurement during Electrolytic Reduction. The instrumentation consisted of a mass flow controller, pump, wet gas meter, and oxygen gas sensor. The oxygen gas was successfully measured using the instrumentation in real time. The measured volume of the oxygen gas was comparable to the theoretically calculated volume generated by the charge applied to the simulated oxide fuel.
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Electrochemical properties of noble metal anodes for Electrolytic Reduction of uranium oxide
Journal of Radioanalytical and Nuclear Chemistry, 2016Co-Authors: Sung-wook Kim, Hyun Woo Kang, Sang-kwon Lee, Eun-young Choi, Wooshin Park, Sun-seok Hong, Jin-mok HurAbstract:Noble metals (Rh, Pd, Ir, and Au) were investigated as O2-evolving anodes for Electrolytic Reduction of UO2 in LiCl–Li2O molten salt to replace Pt anodes, which are gradually consumed owing to Li2PtO3 layer formation. Anodic behaviors of these metals were examined by cyclic voltammetry. Au only showed O2 evolution in a moderate potential range without side reactions, suggesting better electrochemical stability relative to Pt anodes. With Au anodes, UO2 was electrochemically reduced to metallic U. No oxide layer was observed on the surface after the Reduction. However, local dissolution remains a potential issue from a stability viewpoint.
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Distillation characteristics of LiCl–Li2O electrolyte for UO2 Electrolytic Reduction process
Journal of Radioanalytical and Nuclear Chemistry, 2016Co-Authors: Hyun Woo Kang, Sung-wook Kim, Min Ku Jeon, Sang-kwon Lee, Eun-young Choi, Wooshin Park, Sun-seok Hong, Jin-mok HurAbstract:As a process improvement, the distillation and recovery of the salts used in UO2 Electrolytic Reduction is required. The basic characteristics of the distillation of a LiCl–Li2O electrolyte containing UO2 pellets were investigated. UO2 pellets were immersed in LiCl–Li2O (1.0 wt%) and the mixture was subjected to distillation at 930–740 °C under Ar gas at atmospheric pressure. The residual salt consisted of Li2O, whereas the distilled salt was identified as only LiCl. Due to the rapid heat transfer between the evaporator and the receiver, the successful distillation of LiCl at atmospheric pressure was achieved.
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distillation characteristics of licl li2o electrolyte for uo2 Electrolytic Reduction process
Journal of Radioanalytical and Nuclear Chemistry, 2016Co-Authors: Hyun Woo Kang, Sung-wook Kim, Min Ku Jeon, Sang-kwon Lee, Eun-young Choi, Wooshin Park, Sun-seok Hong, Jin-mok HurAbstract:As a process improvement, the distillation and recovery of the salts used in UO2 Electrolytic Reduction is required. The basic characteristics of the distillation of a LiCl–Li2O electrolyte containing UO2 pellets were investigated. UO2 pellets were immersed in LiCl–Li2O (1.0 wt%) and the mixture was subjected to distillation at 930–740 °C under Ar gas at atmospheric pressure. The residual salt consisted of Li2O, whereas the distilled salt was identified as only LiCl. Due to the rapid heat transfer between the evaporator and the receiver, the successful distillation of LiCl at atmospheric pressure was achieved.
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Electrolytic Reduction rate of porous UO2 pellets
Korean Journal of Chemical Engineering, 2016Co-Authors: Min Ku Jeon, Sung-wook Kim, Hyun Woo Kang, Sang-kwon Lee, Eun-young Choi, Sun-seok Hong, Jin-mok Hur, Jeong Lee, Sang-chae Jeon, Ju Ho LeeAbstract:The Electrolytic Reduction rate of porous UO2 pellets in a LiCl salt was investigated for various applied charges. The degree of Reduction (α) value was evaluated from the ratios of cross-sectional areas of the reduced and oxide parts. An analysis of the experimental results revealed that the first-order reaction model is the best geometry function to describe the Reduction reaction. An Electrolytic Reduction rate equation was proposed using the first-order model, although it was available in a limited region of (0≤α≤0.56). A power law based reaction rate equation was also suggested for the whole range of α, and the reaction time for a complete Reduction, estimated using the power law equation, was confirmed through the experimental results. Changes in the Li-Li2O concentration around the reduced pellets for various applied charges were also measured, which increased up to 23 wt% with increasing α.
Eun-young Choi - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic investigation on the behavior of rare earth oxides during Electrolytic Reduction process
Journal of Radioanalytical and Nuclear Chemistry, 2018Co-Authors: Min Ku Jeon, Sung-wook Kim, Eun-young ChoiAbstract:A quantitative analysis on the behavior of rare earth (RE) oxides during the Electrolytic Reduction process was conducted through thermodynamic calculations. The calculation results can identify the oxide form of RE elements as RE2O3 including Ce and Pr, and provide a quantitative explanation on the slow Reduction of RE oxides, compared to UO2, as observed in previous experiments. The concept of the effective salt amount was also introduced to verify the impact of metallic lithium on nearby salt.
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quantitative analysis of barium and strontium in simulated oxide fuel during Electrolytic Reduction and salt distillation
Journal of Radioanalytical and Nuclear Chemistry, 2018Co-Authors: Eun-young Choi, Hyun Woo KangAbstract:Barium and strontium contents of alkaline-earth fission products in simulated oxide fuel were quantitatively analyzed during Electrolytic Reduction and salt distillation. Electrolytic Reduction of the simulated oxide fuel was conducted at 650 °C in molten Li2O–LiCl salt. The residual salt was then separated by salt distillation at 900 °C. Ba and Sr were partially separated from the simfuel and accumulated in the salt during oxide Reduction. Ba and Sr levels of 0.21–0.56 wt% of their initial simfuel masses were found in the distilled salt; 2.28–3.34 wt% were found in the fuel remaining after the salt distillation.
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reoxidation of uranium metal immersed in a li 2 o licl molten salt after Electrolytic Reduction of uranium oxide
Journal of Nuclear Materials, 2017Co-Authors: Eun-young Choi, Min Ku Jeon, Hyun Woo Kang, Sang-chae JeonAbstract:Abstract We present our findings that uranium (U) metal prepared by using the Electrolytic Reduction process for U oxide (UO 2 ) in a Li 2 O–LiCl salt can be reoxidized into UO 2 through the reaction between the U metal and Li 2 O in LiCl. Two salt types were used for immersion of the U metal: one was the salt used for Electrolytic Reduction, and the other was applied to the unused LiCl salts with various concentrations of Li 2 O and Li metal. Our results revealed that the degree of reoxidation increases with the increasing Li 2 O concentration in LiCl and that the presence of the Li metal in LiCl suppresses the reoxidation of the U metal.
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Quantitative Analysis of Oxygen Gas Exhausted from Anode through In Situ Measurement during Electrolytic Reduction
Science and Technology of Nuclear Installations, 2017Co-Authors: Eun-young Choi, Jeong Lee, Dong Hyun Heo, Jin-mok HurAbstract:Quantitative analysis by in situ measurement of oxygen gas evolved from an anode was employed to monitor the progress of Electrolytic Reduction of simulated oxide fuel in a molten Li2O–LiCl salt. The Electrolytic Reduction of 0.6 kg of simulated oxide fuel was performed in 5 kg of 1.5 wt.% Li2O–LiCl molten salt at 650°C. Porous cylindrical pellets of simulated oxide fuel were used as the cathode by loading a stainless steel wire mesh cathode basket. A platinum plate was employed as the anode. The oxygen gas evolved from the anode was exhausted to the instrumentation for in situ measurement during Electrolytic Reduction. The instrumentation consisted of a mass flow controller, pump, wet gas meter, and oxygen gas sensor. The oxygen gas was successfully measured using the instrumentation in real time. The measured volume of the oxygen gas was comparable to the theoretically calculated volume generated by the charge applied to the simulated oxide fuel.
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Electrochemical properties of noble metal anodes for Electrolytic Reduction of uranium oxide
Journal of Radioanalytical and Nuclear Chemistry, 2016Co-Authors: Sung-wook Kim, Hyun Woo Kang, Sang-kwon Lee, Eun-young Choi, Wooshin Park, Sun-seok Hong, Jin-mok HurAbstract:Noble metals (Rh, Pd, Ir, and Au) were investigated as O2-evolving anodes for Electrolytic Reduction of UO2 in LiCl–Li2O molten salt to replace Pt anodes, which are gradually consumed owing to Li2PtO3 layer formation. Anodic behaviors of these metals were examined by cyclic voltammetry. Au only showed O2 evolution in a moderate potential range without side reactions, suggesting better electrochemical stability relative to Pt anodes. With Au anodes, UO2 was electrochemically reduced to metallic U. No oxide layer was observed on the surface after the Reduction. However, local dissolution remains a potential issue from a stability viewpoint.
Kouji Yasuda - One of the best experts on this subject based on the ideXlab platform.
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improving purity and process volume during direct Electrolytic Reduction of solid sio2 in molten cacl2 for the production of solar grade silicon
Energy technology, 2013Co-Authors: Kouji Yasuda, Toshiyuki Nohira, Katsutoshi Kobayashi, Naoya Kani, Tetsuya Tsuda, Rika HagiwaraAbstract:The direct Electrolytic Reduction of solid SiO2 is investigated in molten CaCl2 at 1123 K to produce solar-grade silicon. The target concentrations of impurities for the primary Si are calculated from the acceptable concentrations of impurities in solar-grade silicon (SOG-Si) and the segregation coefficients for the impurity elements. The concentrations of most metal impurities are significantly decreased below their target concentrations by using a quartz vessel and new types of SiO2-contacting electrodes. The Electrolytic Reduction rate is increased by improving an electron pathway from the lead material to the SiO2, which demonstrates that the characteristics of the electric contact are important factors affecting the Reduction rate. Pellet- and basket-type electrodes are tested to improve the process volume for powdery and granular SiO2. Based on the purity of the Si product after melting, refining, and solidifying, the potential of the technology is discussed.
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Fundamental Study on Reduction Rate for Electrolytic Reduction of SiO2 Powder in Molten CaCl2
ECS Transactions, 2013Co-Authors: Tetsuya Toba, Kouji Yasuda, Toshiyuki Nohira, Rika Hagiwara, Koki Ichitsubo, Kenta Masuda, Takayuki HommaAbstract:Direct Electrolytic Reduction of powdery SiO2 has been investigated in molten CaCl2 at 1123 K aiming at a low cost and mass production of solar-grade Si. SiO2 powder was set on a Si plate which was installed at the bottom of the crucible and connected to a graphite rod used as a current lead. SiO2 powder was reduced to Si by cathodic polarization of the Si plate. The Reduction rate was evaluated by the magnitude of the Reduction current, in which three parameters were varied: electrode potential, SiO2 layer thickness, and SiO2 particle size. As a result, the rate-determining step of the Reduction is suggested to be the diffusion of O2- ions inside the reduced porous Si particles filled with the electrolyte. During the Reduction process, however, other factors such as contact resistance between Si particles and porosity of SiO2 particles possibly influence the Reduction rate.
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Diagrammatic Representation of Direct Electrolytic Reduction of SiO2 in Molten CaCl2
Journal of The Electrochemical Society, 2007Co-Authors: Kouji Yasuda, Toshiyuki Nohira, Rika Hagiwara, Yukio H. OgataAbstract:The direct Electrolytic Reduction of solid SiO 2 and an Ag + /Ag reference electrode in molten CaCl 2 were investigated at 1123 K. An Ag + /Ag electrode separated by a mullite tube was confirmed to be a stable reference electrode. The electrochemical window of this melt was 3.27 V at 1123 K. The formation potential of Si-Ca alloys was measured. Combining these experimental data and the reported thermochemical data, a diagram was constructed which shows the equilibrium potentials for the silicon species in molten CaCl 2 containing O 2- ions at 1123 K, where the electrode potential vs Ca 2+ /Ca was plotted against the negative logarithm of the activity of oxide ions in the melt (pO 2- ). The potential-pO 2- diagram explained the behavior of an SiO 2 -contacting electrode during the direct Electrolytic Reduction to silicon and suggested a formation of an intermediate of solid CaSiO 3 , which was confirmed by X-ray photoelectron spectroscopy analysis.
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direct Electrolytic Reduction of solid silicon dioxide in molten licl kcl cacl2 at 773 k
Journal of The Electrochemical Society, 2005Co-Authors: Kouji Yasuda, Toshiyuki Nohira, Yukio H. Ogata, Yasuhiko ItoAbstract:We investigated Electrolytic Reduction of solid SiO 2 by a contacting electrode method in molten LiCl-KCl-CaCl 2 at 773 K. The results of cyclic voltammetry indicated that Reduction of SiO 2 occurs at potential more negative than 0.85 V (vs Ca 2 + , Li + /Ca-Li). Samples were prepared by potentiostatic electrolysis for 2 h at 0.25, 0.50, 0.70, and 1.00 V. Energy dispersive X-ray analysis and Raman spectra clarified that the Reduction products at 0.50 and 0.70 V are composed of amorphous Si and microcrystalline Si. Scanning electron microscope (SEM) observations revealed that the morphology of the produced Si is spongelike with a particle size smaller than 50 nm. The mechanism of Si formation was discussed by comparing the SEM observations and the Raman spectra of the Si samples prepared at 773 and 1123 K. The Reduction mechanism of the direct Electrolytic Reduction of SiO 2 at lower temperature was also discussed.
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Direct Electrolytic Reduction of Solid Silicon Dioxide in Molten LiCl – KCl – CaCl2 at 773 K
Journal of The Electrochemical Society, 2005Co-Authors: Kouji Yasuda, Toshiyuki Nohira, Yukio H. Ogata, Yasuhiko ItoAbstract:We investigated Electrolytic Reduction of solid SiO 2 by a contacting electrode method in molten LiCl-KCl-CaCl 2 at 773 K. The results of cyclic voltammetry indicated that Reduction of SiO 2 occurs at potential more negative than 0.85 V (vs Ca 2 + , Li + /Ca-Li). Samples were prepared by potentiostatic electrolysis for 2 h at 0.25, 0.50, 0.70, and 1.00 V. Energy dispersive X-ray analysis and Raman spectra clarified that the Reduction products at 0.50 and 0.70 V are composed of amorphous Si and microcrystalline Si. Scanning electron microscope (SEM) observations revealed that the morphology of the produced Si is spongelike with a particle size smaller than 50 nm. The mechanism of Si formation was discussed by comparing the SEM observations and the Raman spectra of the Si samples prepared at 773 and 1123 K. The Reduction mechanism of the direct Electrolytic Reduction of SiO 2 at lower temperature was also discussed.