Abstract
The hydrolysis of fused calcium chloride occurs at the initial step in the nickel segregation. This reaction was studied at 1113, 1173 and 1223 K under the experimental condition that equilibrium was attained at the gas-melt interface and the overall rate of the reaction was controlled by the gas diffusion to and from the gas-melt interface by using a slender platinum container. The weight loss of the sample and the amount of the evolved HC1 gas were continuously measured. The overall rate of the reaction was raised at higher temperature and higher moisture content in the mixed feed gas of N2 and H2O. It was found that CaO was formed above 1170 K. It was also formed at 1113 K when the moisture content of the feed gas was 19 pct or less. When the moisture content is higher than 24 pct at 1113 K, however, the reaction becomes more complicated; Ca(OH)2 is formed in addition to CaO both of which are dissolved in the melt. A theoretical calculation was made regarding the hydrolysis in which only CaO is formed in order to verify that the overall rate is controlled by the gas diffusion; it was assumed that the equilibrium is attained at the gas-melt interface and the theoretical weight loss was calculated from the rate of counter-diffusion of H2O and HC1 in the stagnant N2 gas. The theoretical value was in excellent agreement with the measurement.
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H. KONDO formerly a Graduate Student with the Department of Metallurgy, Kyoto University.
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Kondo, H., Asaki, Z. & Kondo, Y. Hydrolysis of fused calcium chloride at high temperature. Metall Trans B 9, 477–483 (1978). https://doi.org/10.1007/BF02654424
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DOI: https://doi.org/10.1007/BF02654424