Abstract
The commonly held view that metallothermic reduction is strictly a chemical reaction and that the process is rate limited by mass transfer has been found to be incomplete. In a study of the production of tantalum powder by the reaction of K2TaF7 with sodium, it has been shown that there are two dominant kinetic pathways, both involving electron transfer. Furthermore, the overall rate of reaction is limited by electron transport between the reactants. This indicates that metallothermic reduction is an “electronically mediated reaction” (EMR). Experiments found that the location of the tantalum deposit and its morphology are governed by the reaction pathway.
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Okabe, T.H., Sadoway, D.R. Metallothermic reduction as an electronically mediated reaction. Journal of Materials Research 13, 3372–3377 (1998). https://doi.org/10.1557/JMR.1998.0459
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DOI: https://doi.org/10.1557/JMR.1998.0459