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.
Citation Information
Publication Year | 1975 |
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Title | Quantitative determination of dawsonite in Green River Shale by powder-sample X-ray diffraction; effect of grinding |
Authors | E-an Zen, Jane M. Hammarstrom |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Journal of Research of the U.S. Geological Survey |
Index ID | 70232651 |
Record Source | USGS Publications Warehouse |
USGS Organization | Eastern Mineral and Environmental Resources Science Center |