Quantitative Determination of Aluminum-substituted Goethite-hematite Mixtures by Mossbauer Spectroscopy
نویسندگان
چکیده
-Mixtures of synthetic Al-substituted goethite (a-Feo.814AloA86OOH) and hematite (a-Fel.658Alo.34203) (75, 50, 25, 3~ hematite by weight) were studied by M6ssbauer spectroscopy to evaluate the use of that technique for quantitative analysis. M6ssbauer spectra for these mixtures, obtained in the temperature range 12-130 K, were better fitted by a distribution of magnetic fields than by two magnetic sextets. Spectra at 80 K were equally as good as those from lower temperature to determine the hematitegoethite ratio. The recoil-free fractions of the individual components were about equal at any fixed temperature, but thickness effects caused as much as 30% error in the determination of the ratio of components in mixtures. Key Words--Aluminum, Goethite, Hematite, M6ssbauer spectroscopy, Quantitative mineralogy.
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