TITLE:
X-Ray Diffraction, Electron Paramagnetic Resonance and Optical Absorption Study of Bauxite
AUTHORS:
Tanguturi Ravindra Reddy, Krishnan Thyagarajan, Ovidio Almanza Montero, Sanapa Reddy Lakshmi Reddy, Tamio Endo
KEYWORDS:
Bauxite; Gibbsite; X-Ray Diffraction (XRD); Electron Paramagnetic; Electron Paramagnetic Resonance; Optical Absorption Spectra; Fe3+; Water Fundamentals
JOURNAL NAME:
Journal of Minerals and Materials Characterization and Engineering,
Vol.2 No.2,
March
14,
2014
ABSTRACT: The bauxite mineral obtained from Araku, Vishakapatnam district of Andhra Pradesh, India is used in the present work. Structural characterization was performed by X-ray diffraction (XRD). The mineral was found to be gibbsite in phase. The transitional metal ions present were investigated using electron paramagnetic resonance (EPR) and optical absorption spectra. The EPR results suggest that Fe3+ has replaced Al3+ in the unit cell of bauxite. The optical absorption spectrum is due to Fe3+ which indicates that it is in distorted octahedral environment. The near-infrared (NIR) spectrum is due to water fundamentals and combination overtones, which confirm the formula of the compound. The impurities in the mineral are identified using spectroscopic techniques.