Determinação de Co, Cu, Fe, Mn e Mo em tantalo com alta pureza usando espectrometria por absorção atomica em forno de grafite

AUTOR(ES)
DATA DE PUBLICAÇÃO

1999

RESUMO

The graphite furnace atomic absorption spectrometry was used as a technique in the determination of the elements cobalt, copper, iron, manganese and molybdenum in tantalum with high purity. In the first stage of this work, the analytical determinations were carried out in the presence of the tantalum matrix. The analytical behavior of the elements of interest was evaluated in the presence of the tantalum matrix, using the electrothermal atomizers of pyrolytic grafite and tantalum carbide coated tube. The results showed that the pyrolytically coated platform was the best electrothermal atomizer, making possible relative standard deviation around 4 to 10% for Co, 6 to 8% for Cu, 7 to 12% for Fe and 3 to 6% for Mn. In the second stage, studies were developed with the extraction of the tantalum matrix, in order to improve the precision and accuracy of the results. Two analytical methodologies was used: liquid-liquid extraction with diantipyrylmethane (DAM) and ion-exchange with the Dowex resin. The results showed that the extraction with DAM were more efficient to recovery the group of the elements of interest, presenting relative standard deviation from 2 to 4% for Co, Cu and Mn, and of 7 to 13% for Fe. On the other hand, the molybdenum was only possible to determine after the ion-exchange process, that made possible a separation larger than 99.9% for tantalum and a relative standard deviation around 2.5% for Mo in GF-AAS. It was not possible to determine molybdenum in the presence of the matrix, because of the formation of molybdenum carbide with high melting point.

ASSUNTO(S)

atomização eletrostatica tantalo extração (quimica)

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