Improve titanate reduction by electro-deoxidation of Ca3Ti2O7 precursor in molten CaCl2

Dong Wang; Sheng Pang; Chun-yue Zhou; Yan Peng; Zhi Wang; Xu-zhong Gong

doi:10.1007/s12613-020-2165-2

Volume 27 Issue 12

Dec. 2020

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Article Navigation > International Journal of Minerals, Metallurgy and Materials > 2020 > 27(12): 1618-1625

Dong Wang, Sheng Pang, Chun-yue Zhou, Yan Peng, Zhi Wang, and Xu-zhong Gong, Improve titanate reduction by electro-deoxidation of Ca₃Ti₂O₇ precursor in molten CaCl₂, Int. J. Miner. Metall. Mater., 27(2020), No. 12, pp. 1618-1625. https://doi.org/10.1007/s12613-020-2165-2

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Dong Wang, Sheng Pang, Chun-yue Zhou, Yan Peng, Zhi Wang, and Xu-zhong Gong, Improve titanate reduction by electro-deoxidation of Ca3Ti2O7 precursor in molten CaCl2, Int. J. Miner. Metall. Mater., 27(2020), No. 12, pp. 1618-1625. https://doi.org/10.1007/s12613-020-2165-2

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Research Article

Improve titanate reduction by electro-deoxidation of Ca₃Ti₂O₇ precursor in molten CaCl₂

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Corresponding author:
Zhi Wang E-mail: zwang@ipe.ac.cn
Received: 4 April 2020; Revised: 11 August 2020; Accepted: 12 August 2020; Available online: 14 August 2020

Abstract

Abstract

The low O²⁻ diffusion rate in the electro-deoxidation of titanium containing compounds by either the OS process or the FFC process leads to a low reaction speed and a low current efficiency. In this study, Ca₃Ti₂O₇ was used as a precursor to improve the reduction speed of titanium. Because of the greater number of “diffusion channels” created in cathode as Ca²⁺ liberates from Ca₃Ti₂O₇ precursor in the electro-deoxidation process, the O²⁻ diffusion rate was improved significantly by using Ca₃Ti₂O₇ instead of CaTiO₃ as precursor. Parallel constant voltage electrolysis (3.2 V) confirms that Ca₃Ti₂O₇ and CaTiO₃ are reduced simultaneously because of their similar crystal structures. However, the reduction area of Ca₃Ti₂O₇ spreads much faster than that of CaTiO₃, indicating a difference in the O²⁻ diffusion rate. Constant voltage cyclic voltammetry (CV) and theoretical analysis of the crystal structure were also conducted to compare the differences between Ca₃Ti₂O₇ and CaTiO₃. The results indicate that using a precursor with a greater number of soluble cations, titanium reduction speed can be greatly improved in the electro-deoxidation process. Finally, a new electrolysis method for converting and recycling excess CaO from the Ca₃Ti₂O₇ precursor was proposed.
- calcium titanate;
- Ca₃Ti₂O₇;
- molten calcium chloride;
- solid-state reaction;
- reaction speed

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