Electrochemical Preparation of Silicon and Its Alloys from Solid Oxides in Molten Calcium Chloride

Jin, Xianbo; Gao, Pei; Wang, Dihua; Hu, Xiaohong; Chen, George

doi:10.1002/ange.200352786

Cited by 60 publications

(53 citation statements)

References 14 publications

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“…It should be pointed out that the above reactions for a compound bimetallic oxide are different from the electroreduction of a simple oxide, such as TiO 2 [13,15,19] and SiO 2 , [16,17] but are very much desired because the Fe particles formed first inside the pellet can surely help the conduction of electrons. It is also likely that the polarisation potential needed for the reduction of CaTiO 3 or TiO 2 is lowered because the newly formed Ti atoms settle to a lower energy state on the nearby Fe particles.…”

Section: Wwwchemeurjorgmentioning

confidence: 99%

A Direct Electrochemical Route from Ilmenite to Hydrogen‐Storage Ferrotitanium Alloys

Wang

et al. 2006

Chemistry A European J

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An unrecognised but predictable need for a hydrogen-supported society is tens or even hundreds of million tonnes of hydrogen-storage materials, and thus challenges existing technologies in terms of resource and economical realities. Ilmenite is an abundant mineral, and ferrotitanium alloys are among the earliest known hydrogen-storage materials. At present, industrial production of ferrotitanium alloys goes through separate extraction of individual metals, followed by a multistep arc-melting process. In particular, the extraction of titanium from ilmenite is highly energy intensive and tedious, accounting for titanium's high market price and restricted uses. This article reports the electrochemical synthesis of various ferrotitanium alloy powders directly from solid ilmenite in molten calcium chloride. More importantly, it demonstrates, for the first time, that such produced alloy powders can be used without further treatment for hydrogen storage and perform comparably with or better than similar products by means of other methods, but cost just a fraction.

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Section: Wwwchemeurjorgmentioning

confidence: 99%

A Direct Electrochemical Route from Ilmenite to Hydrogen‐Storage Ferrotitanium Alloys

Wang

et al. 2006

Chemistry A European J

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“…the 3PI mechanism explained above [17][18][19][20][21][22]27,28] . The initiation-expansion-shrinking-disappearance (IESD) process of the solid (conductive product)/solid (oxide)/liquid (electrolyte) three-phase reaction boundary (TPB), proposed to explain the electro-deoxidation of insulating compounds [29] , fits well with the deoxidation pattern of insulating SiO 2 preforms [23,[30][31][32][33] . Though several such reports are available on the 3PI mechanism of electrodeoxidation of insulating oxides with SiO 2 as the typical example, no study has yet been reported, to the best of our knowledge, which brings out the difference in the mechanism of electrodeoxidation of conducting and non-conducting oxides.…”

Section: Introductionmentioning

confidence: 94%

“…[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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“…On applying a constant voltage between the oxide cathode and carbon anode, oxygen in the cathode is electrochemically ionized, dissolved in the molten salts, and moved to the anode by diffusion, leaving behind pure titanium at the cathode. Titanium, silicon, niobium, chromium, zirconium and tantalum were also prepared by the same method [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Direct electrochemical reduction of Dy2O3 in CaCl2 melt

et al. 2012

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The electrochemical reduction of Dy 2 O 3 in CaCl 2 melt was studied. The cyclic voltammetry, chronoamperometry, AC impedance and constant voltage electrolysis were employed. A single cathodic current peak in the cyclic voltammogram and one response semicircle in the AC impedance spectrum were observed, supporting a one-step electrochemical reduction mechanism of Dy 2 O 3 . No intermediates were observed by XRD, which confirmed the following electrochemical reduction sequence: Dy 2 O 3 ? Dy. The charge transfer resistances and the activation energies involved in the electrochemical reduction step of Dy 2 O 3 were obtained by simulating the AC impedance spectra with equivalent circuits. The electrochemical reduction reaction of Dy 2 O 3 is controlled by the charge transfer process at a low voltage range and by the diffusion process at a high voltage range.

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Electrochemical Preparation of Silicon and Its Alloys from Solid Oxides in Molten Calcium Chloride

Cited by 60 publications

References 14 publications

A Direct Electrochemical Route from Ilmenite to Hydrogen‐Storage Ferrotitanium Alloys

A Direct Electrochemical Route from Ilmenite to Hydrogen‐Storage Ferrotitanium Alloys

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

Direct electrochemical reduction of Dy2O3 in CaCl2 melt

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