STABILITY OF FE2+-BEARING MINERALS DURING OXIDATION PRETREATMENT FOR SOIL ANALYSIS
Four minerals, thuringite, hornblende, biotite and magnetite, in which Fe2+ content represents 91, 83, 78 and 33% of the total Fe content, respectively, were treated with 0 plasma to evaluate the effect of this oxidizing agent on the valence state of the iron. X-ray diffraction analysis and Mössbauer spectroscopy indicated that these minerals were not affected by the treatment within the detection limits of the instruments. The method is thereby acceptable for the decomposition of organic matter in soils; the dry environment inherent in the 0 plasma treatment cannot transport cations susceptible to substitution for those present in the interlayer space. Key words: XRD patterns, Mössbauer spectra, hornblende, thuringite, biotite, magnetite