Spectrophotometric determination of niobium in rocks

L. Paul Greenland; E.Y. Campbell

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USGS · 70232450

Spectrophotometric determination of niobium in rocks

L. Paul Greenland·E.Y. Campbell

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Abstract

After acid decomposition and evaporation to volatilize silica, samples containing 0.5 6 μ g Nb are fused with pyrosulfate and dissolved in hydrochloric acid tartaric acid. Niobium is separated by thiocyanate extraction with amyl alcohol and back-extracting from the organic solvent with dilute hydrofluoric acid. Niobium is reacted with 4-(2-pyridylazo)-resorcinol to obtain a colored species. Analytical error, estimated from replicate analyses of eight U.S. Geological Survey standard rocks, ranges from 2.9 to 6.4 percent at the 1 27 μ g/g Nb level.

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L. Paul Greenland, E.Y. Campbell. 1974. Spectrophotometric determination of niobium in rocks. https://pubs.usgs.gov/publication/70232450

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