Cinética de carbocloruración de los pentóxidos de tantalio y de niobio

E. Allain; I. Gaballah; F. García; S. Ferreira; J. N. Ayala; A. Hernández

doi:10.3989/revmetalm.1999.v35.i4.630

Carbochlorination kinetics of tantalum and niobium pentoxides

Authors

E. Allain University of Missouri-Rolla, School of Mines and Metallurgy. Center of Pyrometallurgy
I. Gaballah Laboratoire Environnement et Minéralurgie (LEM)
F. García Centro Nacional de Investigaciones Metalúrgicas, CENIM (CSIC)
S. Ferreira Centro Nacional de Investigaciones Metalúrgicas, CENIM (CSIC)
J. N. Ayala Centro Nacional de Investigaciones Metalúrgicas, CENIM (CSIC)
A. Hernández Centro Nacional de Investigaciones Metalúrgicas, CENIM (CSIC)

DOI:

https://doi.org/10.3989/revmetalm.1999.v35.i4.630

Keywords:

Carbochlorination, Tantalum pentoxide, Niobium pentoxide, Tin furnace slag

Abstract

The carbochlorination kinetics of pure Nb₂O₅ and Ta₂O₅ by gas mixture (C1₂ + CO + N₂) between 380 and 1,000 °C is studied. A calculation of the standard free energy of the carbochlorination reactions is made. A diagram of the phases stability is drawn. The influence of the gas flow, temperature and the pardal pressure of Cl₂ and CO at temperatures below 650 °C on the reaction rate is studied. The apparent activation energy is approximately 75 and 110 kJ/mol for Nb₂Os and Ta₂O₅, respectively. At temperatures above 650°C the Arrhenius diagram presents an anomaly which may be attributed to the decomposition of the COCl₂ formed in situ. The apparent reaction order of the carbochlorination of these oxides against Cl₂+CO is approximately 2. The carbochlorination rates of these oxides are much greater than those of chlorination by Cl₂ + N₂. The carbochlorination kinetics of tin furnace slag leaching concentrates containing tantalum and niobium compounds are also studied and compared with the carbochlorination kinetics of the pure oxides.

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Published

1999-08-30

How to Cite

Allain, E., Gaballah, I., García, F., Ferreira, S., Ayala, J. N., & Hernández, A. (1999). Carbochlorination kinetics of tantalum and niobium pentoxides. Revista De Metalurgia, 35(4), 242–248. https://doi.org/10.3989/revmetalm.1999.v35.i4.630

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Issue

Vol. 35 No. 4 (1999)

Section

Articles

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