Production of niobium powder by electronically mediated reaction (EMR) using calcium as a reductant

Okabe, TH and Waseda, Y and Jacob, KT and Park, I (1999) Production of niobium powder by electronically mediated reaction (EMR) using calcium as a reductant. In: Journal of Alloys and Compounds, 288 (1-2). pp. 200-210.

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Abstract

Explored in this study is an electronically mediated reaction (EMR) route for the production of niobium powder using calcium as a reductant for niobium oxide (Nb2O5). Feed material, Nb2O5, and reductant calcium alloy containing aluminum and nickel were charged into electronically isolated locations in a molten salt (e.g. CaCl2) at 1173 K. The current flow through an external path between the feed and reductant locations was monitored. A current approximately 0.4 A was measured during the reaction in the external circuit connecting cathode and anode location. Niobium powder with low aluminum and nickel content was obtained although liquid Ca–Al–Ni alloy was used as the reductant. This clearly demonstrates that niobium metal powder can be produced by an electronically mediated reaction (EMR), without direct physical contact between feed (Nb2O5) and reductant (calcium). Mechanism of calciothermic reduction of Nb2O5 in the molten salt is discussed using an isothermal chemical potential diagram.

Item Type:	Journal Article
Publication:	Journal of Alloys and Compounds
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Niobium;Metallothermic reduction;Thermodynamics; Electrochemistry;Reduction process
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	29 Dec 2011 10:22
Last Modified:	29 Dec 2011 10:22
URI:	http://eprints.iisc.ac.in/id/eprint/42698

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