ELABORATION OF MIXED TANTALUM AND NIOBIUM CARBIDES FROM TANTALITE MINERAL (Fe,Mn)(Ta1-xNbx)2O6O6

The process consists in melting the ore with potassium pyrosulphate, then performing a lixiviation with a concentrated HCl solution. During the latter reaction, iron and manganese oxides are converted into water-soluble chlorides while the fused mass containing K, Nb and Ta is not dissolved. The pre...

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Bibliographic Details
Published in:Journal of materials science 2002-01, Vol.37 (10), p.2117-2123
Main Authors: Ciaravino, C, Medeiros F, F P, De Souza, C P, Roubin, M
Format: Article
Language:English
Online Access:Get full text
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Summary:The process consists in melting the ore with potassium pyrosulphate, then performing a lixiviation with a concentrated HCl solution. During the latter reaction, iron and manganese oxides are converted into water-soluble chlorides while the fused mass containing K, Nb and Ta is not dissolved. The precipitate (Ta1-xNbx)(OH)5 is washed and submitted to a reaction of complexation with oxalate ions in an aqueous environment. This reaction involves the formation of a water-soluble oxalic complex containing Ta and Nb. The Ta and Nb carbides are obtained by submitting the oxalic complex of chemical formula (NH4)3(Ta1-xNbx)O(C2O4)3.nH2O to a gas solid reaction in a methane-hydrogen atmosphere at 1273 K. The oxalic precursor and their resultant mixed carbides are characterised by atomic absorption and IR spectroscopies, DTA, TGA, laser granulometry, XRD and TEM. 30 refs.
ISSN:0022-2461