Molecular dynamics simulations of the local structure and physicochemical properties of CaCl2 molten salt

Hui Li; Xuexue Wei; Jinglong Liang; Weigang Cao; Zongying Cai; Yu Yang

doi:10.1515/ijcre-2023-0228

Article

Molecular dynamics simulations of the local structure and physicochemical properties of CaCl₂ molten salt

Hui Li , Xuexue Wei , Jinglong Liang , Weigang Cao , Zongying Cai and Yu Yang

Published/Copyright: February 9, 2024

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From the journal International Journal of Chemical Reactor Engineering Volume 22 Issue 4

Abstract

CaCl₂ molten salt, as a common electrolyte in the process of molten salt electrolysis, has a high decomposition potential and a strong ability to bind O²⁻. So the study of the structure and properties of CaCl₂ is significant for the molten salt electrolysis. In this paper, molecular dynamics simulations (MD) method was used to investigate the variation rule of the local structure and physicochemical properties of CaCl₂ molten salt with temperature. The results show that the temperature has less effect on the heterozygous ion pairs and more effect on the homozygous ion pair. With the increase of temperature, the interaction between ion pairs is weakened, the coordination number decreases, the local structure changes a little, and the structural configuration tends to be an irregular octahedral structure with vacancies. The calculated self-diffusion coefficients, viscosities, and ionic conductivities are consistent well with the reality, but there is a significant error in densities due to the strong polarization effect of Ca²⁺ compared to the reality. The local structure directly determines the thermodynamic properties of the molten salts. This study promotes the basic theoretical research on alkaline earth metal-containing molten salts and is an important reference for the study of molten salt electrolysis process.

Keywords: CaCl2 molten salt; MD method; local structure; physicochemical properties; relationship

Corresponding authors: Jinglong Liang and Weigang Cao, Key Laboratory of Ministry of Education for Modern Metallurgy Technology and College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063009, Hebei, China, E-mail: ljl@ncst.edu.cn (J. Liang), caoweigang@ncst.edu.cn (W. Cao)

Funding source: National Natural Science Foundation of China

Award Identifier / Grant number: No.52074125

Acknowledgments

This work was supported by the National Natural Science Foundation of China under Grant No. 52074125 and Tangshan Science and Technology Innovation Team Training Program Project under Grant No. 21130207D.

Research ethics: Not applicable.
Author contributions: The author have accepted responsibility for the entire content of this manuscript and approved its submission.
Competing interests: The author state no conflict of interest.
Research funding: This work was supported by the National Natural Science Foundation of China (No.52074125).
Data availability: The raw data can be obtained on request from the corresponding author.

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Received: 2023-12-06

Accepted: 2024-01-27

Published Online: 2024-02-09

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https://doi.org/10.1515/ijcre-2023-0228

Keywords for this article

CaCl2 molten salt; MD method; local structure; physicochemical properties; relationship