Quantitative determination of dawsonite in Green River Shale by powder-sample X-ray diffraction; effect of grinding

Journal of Research of the U.S. Geological Survey
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Abstract

In an effort to evaluate the method of quantitative analysis by X-ray diffraction as a means of determining dawsonite abundances in Green River" oil shale, we performed a series of grinding experiments. Weighed mixtures of dawsonite + quartz and dawsonite + quartz + shale were ground for preset lengths of time, and the following X-ray diffraction peaks were measured for intensity: dawsonite (110) at 15.6 2θ and (211) (002) at 32.1° 2θ, and quartz (100) at 20.9° 2θ and (101) at 26.6° 2θ. Heights and areas were measured. Intensity ratios were plotted as functions of grinding time with a calculated probable error. Intensity ratios generally decrease as grinding time increases. The intensity of the 15.6° peak, D15.6°, is most affected, and the most drastic reduction occurs during the first 20 min of grinding. The D32.1° peak is least sensitive to grinding but is subject to interference by other minerals in the shale. We conclude that the X-ray diffraction method is not well adapted to the routine quantitative determination of dawsonite in oil shale of the Green River Formation.

Publication type Article
Publication Subtype Journal Article
Title Quantitative determination of dawsonite in Green River Shale by powder-sample X-ray diffraction; effect of grinding
Series title Journal of Research of the U.S. Geological Survey
Volume 3
Issue 1
Year Published 1975
Language English
Publisher U.S. Geological Survey
Contributing office(s) Eastern Mineral and Environmental Resources Science Center
Description 10 p.
First page 21
Last page 30
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