Revaluation of equilibrium quotient between titanium ions and metallic titanium in NaCl–KCl equimolar molten salt

Sekimoto, Hidehiro; Nosé, Yukihiko; Uda, Tetsuya; Uehara, Akihiro; Yamana, Hideaki; Sugimura, Hiroyuki

doi:10.1016/j.jallcom.2011.02.090

Cited by 13 publications

(6 citation statements)

References 16 publications

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“…The intermediate valence will lead to disproportionation reactions. 3,4 With the presence of metallic titanium, the equilibrium between different valence ions can be described by the following reactions:…”

Section: Introductionmentioning

confidence: 99%

The influence of fluoride ions on the equilibrium between titanium ions and titanium metal in fused alkali chloride melts

Song

Wang

et al. 2016

Faraday Discuss.

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KF is employed as a source of fluoride ions added to the melt to disclose the influence of fluoride on the disproportionation reactions of titanium ions, 3Ti(2+) = 2Ti(3+) + Ti, and 4Ti(3+) = 3Ti(4+) + Ti. The results reveal that the equilibrium transferred to the right direction for the first reaction and the apparent equilibrium constant increased sharply, mainly because of the formation of coordination compounds: TiFi(3-i). The accurate values of the equilibrium constants referring to the formation reactions of Ti(3+) + iF(-) = TiFi(3-i) (i = 1-6) in NaCl-KCl melt at 1023 K were evaluated with a best fit least squares method. It is also revealed that the stable states of the coordination compounds are TiF(2+), TiF2(+), TiF4(-) and TiF6(3-). Moreover, the Gibbs free energies for complex formation were estimated. Ti(2+) was undetectable when the concentration of fluoride ion was high enough. The equilibrium constant for the formation reaction, Ti(4-) + 6F(-) = TiF6(2-), was evaluated. The equilibrium constant, Kc2, for the disproportionation reaction 4Ti(3+) = 3Ti(4+) + Ti, in chloride melt was determined as 0.015.

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Section: Introductionmentioning

confidence: 99%

The influence of fluoride ions on the equilibrium between titanium ions and titanium metal in fused alkali chloride melts

Song

Wang

et al. 2016

Faraday Discuss.

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“…The volatility of the K c1 value in molten salt that evaluated by the HCl treated is relatively small. Sekimoto [21] and other studies have shown that this is due to the coordination reaction (12) between Ti 3+ and O 2À in the molten salt. The removal of oxygen from the molten salt by HCl will eliminate the effect of TiOCl on the concentration determination to some extent.…”

Section: The Formation Of Tiocl In Molten Saltmentioning

confidence: 82%

Effect of Electrolytic Compositions in Kinetics Mechanism of High-Purity Titanium Electrochemical Extraction Process

Song¹,

Che²,

Shu³

et al. 2020

Recent Advancements in the Metallurgical Engineering and Electrodeposition

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High pure titanium, which is a critical material used for integrated circuit (IC) manufacturing, can be extracted by molten salt-electrolysis process. It will be widely used in the future for the process, is simple and easy, to achieve continuous production. However, some scientific questions need to be clarified at present. (1) Current efficiency needs to be enhanced by way of electrolyte designing and selection; (2) Product quality needs to be improved by means of electrolyte purification; (3) Electrolytic parameters need to be optimized for obtaining a better morphology. Above on, this chapter aims to explore the behaviors of titanium ions in various molten salts by means of chemical analysis and electrochemical testing. The complexes will be discussed for clarifying the influence of electrolytic compositions on kinetics mechanisms of the electrolysis process and the properties of the molten salt. A quantitative method for estimating oxygen content will be also discussed for the purpose of optimizing the composition of electrolytes. The chapter will provide a better understanding mechanism of kinetics of high pure titanium electrolysis, and the basic theory and experimental data can be used for reference in the industrialization process.

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“…It was evaluated by Mellgren, Kreye, Li, Sekimoto et al with determining the concentrations of Ti 2+ and Ti 3+ , respectively. [4][5][6][7][8][9] Results show that the equilibrium constant dispersed under different experimental condition and increased significantly with the decreasing of the molar fraction of Ti 2+ . Actually, the K c should be a constant as the solutes (TiCl 3 , TiCl 2 ) obey Henry's law under the condition of low titanium ions concentration.…”

Section: Introductionmentioning

confidence: 99%

“…Such a tendency indicates that there is an underestimation of the concentration of Ti 2+ or an overestimation of Ti 3+ caused by some systematic errors or by the effect of some impurities in molten salt. According to the study of Sekimoto et al, 7 Ti 3+ could reacts with O 2¹ and Cl ¹ to form TiOCl(s). The ion of Ti 3+ both in TiOCl(s) and in molten salt can be oxidized by the titrant agent, and they cannot be distinguished.…”

Section: Introductionmentioning

confidence: 99%

The Equilibrium between Titanium Ions and Metallic Titanium in the Molten Binary Mixtures of LiCl

et al. 2014

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The equilibrium constant, K c , of the reaction 3Ti 2+ = 2Ti 3+ + Ti was studied in the molten binary mixtures of LiCl. The accurate values of K c were calculated by the best-fitting method under consideration of the TiOCl(s) dissolution at temperature of 973 K, 1023 K and 1073 K, respectively. The fitted concentration of O 2− was verified by emf method with yttria-stabilized zirconia electrode (YSZE). The influence of the cation radius of electrolyte on the equilibrium constant was studied in molten binary mixtures of LiCl at 1023 K on the basis of the reliable method for obtaining accurate value of K c . It was found that the K c values decreased from 0.59 to 0.27 with the concentration of LiCl increasing at 1023 K. More importantly, results disclosed that the values of K c correspond with polarizing power no matter in CsCl-LiCl or KCl-LiCl system.

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Revaluation of equilibrium quotient between titanium ions and metallic titanium in NaCl–KCl equimolar molten salt

Cited by 13 publications

References 16 publications

The influence of fluoride ions on the equilibrium between titanium ions and titanium metal in fused alkali chloride melts

The influence of fluoride ions on the equilibrium between titanium ions and titanium metal in fused alkali chloride melts

Effect of Electrolytic Compositions in Kinetics Mechanism of High-Purity Titanium Electrochemical Extraction Process

The Equilibrium between Titanium Ions and Metallic Titanium in the Molten Binary Mixtures of LiCl

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