Electrochemical reduction of TiO2 powders in molten calcium chloride

Vishnu, D. Sri Maha; Sanil, N K; Shakila, L.; Sudha, R.; Mohandas, K.S.; Nagarajan, K.

doi:10.1016/j.electacta.2015.01.105

Cited by 36 publications

(27 citation statements)

References 20 publications

(22 reference statements)

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“…The regions of the anode that are at the gas-electrolyte interface are generally seen to be highly corroded. The gas-electrolyte interface at the anode is apparently experiencing erosion due to intense gas evolution during the electrolysis time as was also observed and reported by Srimaha Vishnu et al 26) . As already brought out, the similar co-relative trends observed with the CO 2 -time pro le and DC current -time pro le, could be used for estimating CO 2 in the vent gases by simpler linear best t methods.…”

Section: Resultssupporting

confidence: 66%

Carbon Dioxide (CO2) Released in the Electrochemical Reduction of Titanium Dioxide (TiO2) to Titanium Metal

et al. 2017

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Studies pertaining to kinetic aspects of the direct electrochemical reduction process of titanium preparation from TiO 2 have not been substantial for determining the conversion time precisely. The solid state reduction process does not permit measuring either the rate of formation of product or the rate of depletion of the feed stock. In this work an attempt has been made to study the applicability of variation of CO 2 (the product gas) in the vent gases of the electrolytic cell to approximate the bulk process kinetics of the process. From the electrolysis current trend, it might be possible to estimate CO 2 pro le during the electrolysis time so as to utilize the same for inferring optimal time of the electrochemical reduction process.

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Section: Resultssupporting

confidence: 66%

Carbon Dioxide (CO2) Released in the Electrochemical Reduction of Titanium Dioxide (TiO2) to Titanium Metal

et al. 2017

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“…2.5 V and 1173 K, 3.1 V and 1098 K, and 3.1 V and 1173 K, all for a duration of 18 h. In each case, the current peaked initially, then dropped off, and finally approached a constant background value, as it had likewise been observed for the reduction of pure TiO 2 . 35,36) As expected, the magnitude of the current increased with increase in applied potential and electro-deoxidation temperature. The insets of the figure are photographs of the processed samples and show that these were in the form of powder, fragments, or a complete disc.…”

Section: Characterisation Of Mixed Oxide Precursorsupporting

confidence: 74%

“…This is expected for Ti sponge prepared by electro-deoxidation. 35,36,38) The average particle size in the samples grew from slightly below 1 µm ( Fig. 4(g)), via around 23 µm ( Fig.…”

Section: Characterisation Of Mixed Oxide Precursormentioning

confidence: 98%

“…This is again similar to the findings for pure Ti. 35,36,38) The electro-deoxidation of almost all metal oxides proceeds in a series of steps, often involving the transient formation and decomposition of Ca metallates. In-depth studies have established the following kinetic pathways for TiO 2 , Ta 2 O 5 and Nb 2 O 5 .…”

Section: Characterisation Of Mixed Oxide Precursormentioning

confidence: 99%

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Molten Salt Electrochemical Synthesis, Heat Treatment and Microhardness of Ti–5Ta–2Nb Alloy

et al. 2019

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Alloy of composition Ti5Ta2Nb (numbers in mass%) was synthesised directly from the corresponding mixed metal oxides via the FFC-Cambridge process. Compacted powder discs of TiO 2 Ta 2 O 5 Nb 2 O 5 were cathodically polarised against a graphite anode in a molten CaCl 2 electrolyte, and the effect of various process parameters on the synthesis of the alloy was investigated. The samples retained their disc-type shape throughout the oxide-to-metal conversion under appropriate processing conditions. XRD analysis showed that the electrochemically prepared alloy existed as single-phase ¡-Ti and changed into dual-phase (¡+¢)-Ti upon heat treatment. SEM/EDX analysis revealed a nodular porous microstructure and confirmed the intended chemical composition. Backscattered SEM analysis after heat treatment provided direct evidence of micron-sized ¢-phase precipitates at the boundaries of the ¡-phase particles. Microhardness of the heat-treated alloy compared well with literature data for the same material prepared by conventional metallurgical methods. Overall, the study has demonstrated the feasibility of the single-step electrochemical fabrication of Ti5Ta2Nb alloy bodies directly from oxides for structural application.

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“…[3,7,8] . Several studies have been reported on the electrochemical reduction of oxides such as TiO 2 [1,3,5,[8][9][10][11] , Nb 2 O 5 [7,12,13] , UO 2 [14][15][16] , SiO 2 [17][18][19][20][21][22][23][24][25][26] etc. The process is being pursued in view of production of solar grade silicon as well [27] .…”

Section: Introductionmentioning

confidence: 99%

Difference in the Mechanism of Electrochemical Deoxidation of Conducting and Non-conducting Solid Oxide Preforms: An Experimental Demonstration with TiO2 and SiO2 Pellet Electrodes in CaCl2 Melt

D¹,

Sanil²,

Ks³

2017

Res. Rev. J Mat. Sci

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Powder compacted and sintered solid oxide preforms, generally shaped as thin pellets, have been used as the negative electrode of a molten salt electro-deoxidation cell and deoxidation of the electrode is greatly influenced by its electrical conductivity. The deoxidation pattern of electron conducting and non-conducting oxide preforms should, therefore, be different. In order to demonstrate this experimentally, novel electrochemical experiments were carried out with electron conducting TiO 2 and non-conducting SiO 2 pellet electrodes in calcium chloride melt at 1173 K. The experimental results have shown, as already reported by many previously, that three physically distinct phases, viz. the solid electron conductor, the oxide and the electrolyte melt should coexist for electro-deoxidation of non-conducting SiO 2 electrode but only two physically distinct phases, viz. the oxide and the electrolyte melt need only to coexist in the case of conducting TiO 2 electrode. It is demonstrated in this study, for the first time, that the 3 Phase Interline (3PI) mechanism, proposed to explain electro-deoxidation of solid oxides in general, stands reduced to 2 Phase Interface (2 PI) mechanism in the case of conducting oxides.

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Electrochemical reduction of TiO2 powders in molten calcium chloride

Cited by 36 publications

References 20 publications

Carbon Dioxide (CO<sub>2</sub>) Released in the Electrochemical Reduction of Titanium Dioxide (TiO<sub>2</sub>) to Titanium Metal

Carbon Dioxide (CO<sub>2</sub>) Released in the Electrochemical Reduction of Titanium Dioxide (TiO<sub>2</sub>) to Titanium Metal

Molten Salt Electrochemical Synthesis, Heat Treatment and Microhardness of Ti–5Ta–2Nb Alloy

Difference in the Mechanism of Electrochemical Deoxidation of Conducting and Non-conducting Solid Oxide Preforms: An Experimental Demonstration with TiO2 and SiO2 Pellet Electrodes in CaCl2 Melt

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