Classification in 4 types for bauxites of NE, Spain was stated by Combes (1) and then updated in several papers (29, (3), (4).
The Type 1 bauxites correspond to “ss” bauxites of Bardossy (5) and contains the kaolinites of lower FWHM values (6), and were formed from deposits of Types 2 and 3, (1) (4).
A set of kaolinite rich samples representative of different types of bauxites in the Maestrazgo was studied by powder XRD (Philips XPERT diffractometer PW302, data collection: step scanning: 0.02º - 20 sec from 11 to 13.2º 2θ for microstructural analysis of kaolinite in clay fractions. Mineral contents estimation in whole samples was determined by the reference intensity method (7)). Microstructural analysis of kaolinite was performed by the Voigt function method (8) using 001 reflection and LaB6 (NIST SRM660a) as standard. Winfit software (available at http://www.ccp14.ac.uk) was used for fitting.
The ranges of the found values for FWHM (º2θ), <Dv> (Å) and e, are respectively: 0,148-0,428, 150-815 and 0,0019-0,0135.
No clear differences were found in the mineralogical composition of the different types of bauxites, being the main feature of type 1 bauxites the greater values for volume weighted <Dv> sizes from 001 kaolinite reflections. That characteristic for this type of bauxite is related to a longer crystallite growth along ferrallitic alteration and subsequent processes, in agreement with the geological properties of the bauxite deposits.
The highest values for the e strain parameter have been found in kaolinites of bauxites of types 2 and 3 bauxites. The performed sampling does not allow the identification of lower e values for the type 1 bauxite.

References
1. Combes, P.J.: Mém. Centre d'Etudes et Rech. Geol. et Hydrogéol. Montpellier 1969.
2. Molina, J.M.; Salas, R.: Cuad. Geol. Ibérica, 7 (1993), 207-230.
3. La Iglesia, A.; Ordoñez, S.: Bol. Soc. Esp. Mineral, 13(1990), 81-90.
4. Ordóñez, S.; Fort, R.; Bustillo, M.: Est. Geol., 46 (1990), 373-384.
5. Valeton, I.: Bauxites. Developments in Soil Science., Nº 2. Elsevier, Amsterdam 1972
6. Cozzi, G.; Bastida, J.; Alvarez Larena, A.; Martinez, S.; Pardo, P: Geo-Temas, 8 (2005), 42-46.
7. Hubbard, C. R.; Snyder, R.: RIR - Measurement and Use of RIR in Quantitative X-ray Diffraction. Powder Diff. 3 (1988), 2, 74-77.
8. Langford, J.I.: A rapid method for analysing the breadths of diffraction and spectral lines using the Voigt function. J. Appl. Crystallogr. 11 (1978), 10–14.

Acknowledgements. Generalitat Valenciana project: No GV02-527.

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