Abstract

NETE, Motlalepula; PURCELL, Walter; SNYDERS, Ettienne  and  NEL, Johann T.. Alternative dissolution methods for analysis of niobium containing samples. S.Afr.j.chem. (Online) [online]. 2010, vol.63, pp.130-134. ISSN 1996-840X.

Inductively coupled plasma optical emission spectrometry was applied for the qualitative and quantitative analyses of the different high purity Nb containing samples such as Nb metal, Nb₂O₅ and NbF₅. Microwave-assisted digestion of the Nb compounds with concentrated H₂SO₄ in PTFE vessels produced Nb recoveries of 99.90 ± 0.08 % for Nb metal, 98.8 ± 0.7 % for Nb₂O₅ and 100.7 ± 0.4 % for NbF₅. Fusion of Nb₂O₅ with Li₂B₄O₇ flux and the subsequent dissolution of the melt with concentrated H₂SO₄ resulted in the precipitation of H₃BO₃ under these conditions. Methanol was added to the reaction mixture to convert the boric acid into the volatile methyl ester in an effort to remove the excess H₃BO₃. This procedure yielded a recovery of 103±2%for the pure Nb₂O₅ sample.

Keywords : Niobium samples; microwave dissolution; fusion dissolution; qualitative analysis; quantitative analysis; validation.

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