TY - JOUR
T1 - The influence of fluoride ions on the equilibrium between titanium ions and titanium metal in fused alkali chloride melts
AU - Song, Jianxun
AU - Wang, Qiuyu
AU - Wu, Jinyu
AU - Jiao, Shuqiang
AU - Zhu, Hongmin
N1 - Funding Information:
The authors gratefully acknowledge the support of the National Natural Science Foundation of China (No. 51322402) and the National High Technology Research and Development Program of China (863 Program, No. 2012AA062302).
Publisher Copyright:
© 2016 The Royal Society of Chemistry.
Copyright:
Copyright 2016 Elsevier B.V., All rights reserved.
PY - 2016
Y1 - 2016
N2 - 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, 3Ti2+ = 2Ti3+ + Ti, and 4Ti3+ = 3Ti4+ + 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: TiFi3-i. The accurate values of the equilibrium constants referring to the formation reactions of Ti3+ + iF- = TiFi3-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 TiF2+, TiF2+, TiF4- and TiF63-. Moreover, the Gibbs free energies for complex formation were estimated. Ti2+ was undetectable when the concentration of fluoride ion was high enough. The equilibrium constant for the formation reaction, Ti4- + 6F- = TiF62-, was evaluated. The equilibrium constant, Kc2, for the disproportionation reaction 4Ti3+ = 3Ti4+ + Ti, in chloride melt was determined as 0.015.
AB - 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, 3Ti2+ = 2Ti3+ + Ti, and 4Ti3+ = 3Ti4+ + 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: TiFi3-i. The accurate values of the equilibrium constants referring to the formation reactions of Ti3+ + iF- = TiFi3-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 TiF2+, TiF2+, TiF4- and TiF63-. Moreover, the Gibbs free energies for complex formation were estimated. Ti2+ was undetectable when the concentration of fluoride ion was high enough. The equilibrium constant for the formation reaction, Ti4- + 6F- = TiF62-, was evaluated. The equilibrium constant, Kc2, for the disproportionation reaction 4Ti3+ = 3Ti4+ + Ti, in chloride melt was determined as 0.015.
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U2 - 10.1039/c6fd00007j
DO - 10.1039/c6fd00007j
M3 - Article
AN - SCOPUS:84982182181
VL - 190
SP - 421
EP - 432
JO - Faraday Discussions
JF - Faraday Discussions
SN - 1364-5498
ER -