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Rock Analysis by X-Ray Fluorescence Spectroscopy

Published online by Cambridge University Press:  06 March 2019

Arthur A. Chodos
Arthur A. Chodos*
Affiliation:
California Institute of Technology, Pasadena, California, J. J. R. Branco of the Universidade de Minas Gerais, Brazil, and C. G. Engel of the United States Geological Survey
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Abstract

Our laboratory has been interested in the use of the X-ray spectragraph for routine rock analysis within limited rock types. This paper is meant as a progress report and to indicate the direction of our work on amphibolites to others interested ill the problem of rock analysis.

Even with the use of flow counters and pulse discriminators the intensities of the magnesium, aluminum and silicon peaks are quite low and most dilution techniques may not be used. The direct determination of major elements (except sodium) yields results directly comparable to the chemical results for potassium; manganese and titanium in the range from 0: 1 to 3% as the oxides. For iron (10-20%), calcium (8-12%) and silicon (45-52%) the accuracy is 2-3% but for each element occasional samples will be 5% from the chemical values. Aluminum and magnesium yield erratic results.

The use of ratios between elements occurring in. the samples yields slightly improved accuracies. The use of a strong absorber such as tungstic acid (40% by weight) greatly improves the ratios for aluminum and magnesium., without appreciably affecting their intensities. By a combination of the direct and tungstic acid techniques it is possible to attain accuracies of 2-3% with analysis time of two hours. At present we are attempting a combination with an internal standard method to yield greater accuracy.

Type
Research Article
Information
Advances in X-Ray Analysis , Volume 1: Sixth Annual Conference on Industrial Applications of X-ray Analysis, August 7-9, 1957 , 1957 , pp. 315 - 327
Copyright
Copyright © International Centre for Diffraction Data 1957

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References

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