Structural changes in clays subjected to heat treatment: an analysis by structural refinement using the Rietveld method

Authors

  • Mauro Quiroga Agurto UNIVERSIDAD NACIONAL MAYOR DE SAN MARCOS
  • Elvira Leticia Zeballos Velásquez UNIVERSIDAD NACIONAL MAYOR DE SAN MARCOS
  • Felipe Americo Reyes Navarro UNIVERDIDAD NACIONAL MAYOR DE SAN MARCOS

DOI:

https://doi.org/10.31349/RevMexFis.67.061602

Keywords:

Clay, Dehydration, X-ray Diffraction, Rietveld Method.

Abstract

Structural factors in clays influence their physical properties. Therefore, it is particularly important to understand the effects of heat treatment on the structure of the material during the ceramic process. In this work, we have analyzed clays from quarries in the Cerro de Pasco region, Peru, to evaluate their characteristics and the structural changes produced by heating, particularly in the interlaminar region. The samples were thermally treated between 150 oC and 800 oC with intervals of 50 oC. To evaluate the structural changes produced by temperature, X-ray diffraction were carried out before and after each heat treatment. The qualitative analysis of the measurements allowed to identify the mineralogical composition of the samples, finding phases of calcium montmorillonite, kaolinite, illite and quartz. The quantitative analysis by the Rietveld method found structural changes, particularly in the Ca-montmorillonite expansive clay. It was also possible to determine the decrease in the weight percentage of the kaolinite until the collapse of its structure between 450 °C and 500 °C. The illite presented greater thermal stability, with slight variations in its weight percentage during heat treatment, without compromising its structure. Although the quartz phase did not show relevant structure changes, it slightly increased its weight percentage with increasing temperature.

References

J. Linares, F. Huertas and J. Campel. La arcilla como material cerámico. Características y comportamiento (Clays as ceramic material. Characteristics and behavior). Revistas de la Universidad de Granada, Cuadernos de Prehistoria y Arqueología de la Universidad de Granada, Vol. 8 (1983) 479–490.

Thomas J. Pinnavaia, Expanded Clays and Other Microporous Solids. Eds. Mario L. Occelli and Harry E. Robson, first edition (Springer, US, 1992).

E.L. Zeballos, M.V. Miñano, P.C. Melero, E. Tello, A.L. Trujillo and M.E. Mejía. Caracterización de arcillas de Nazca por difracción de rayos X y refinamiento estructural por el Método de Rietveld (Characterization of clays from the Nazca by X-ray difraction and structural refinament using the Rietveld method). Int. Electron. J. Nanoc. Moletrón. Vol. 11:1 (2013) 2001–2018.

P.C. Melero. Análisis del efecto térmico en la estructura de arcillas de Chulucanas por difracción de rayos-x, refinamiento Rietveld y técnicas complementarias (Analysis of the thermal effect on the clay structure of the Chulucanas town by X-ray diffraction, Rietveld refinement and complementary techniques). Licentiate thesis (UNMSM, Lima, Peru, 2015).

E.L. Zeballos, P.C. Melero, A.L. Trujillo and M.E. Mejía. Estudio estructural de arcillas de Chulucanas por difracción de rayos X y método de Rietveld (A study on clay structure of samples from the Chulucanas town using X-ray diffraction and the Rietveld method). Revista Materia, Vol. 19:2 (2014) 159–170.

H.P. Klug and L.E. Alexander. X-ray diffraction procedures for polycrystalline and amorphous materials (John Wiley & Sons USA, 1974).

M.M. Moore and R.C. Reynolds Jr. X-ray diffraction and the identification and analysis of clay minerals, 2 ed. (Oxford University Press, Oxford, 1997).

G. Will. Powder diffraction: the Rietveld method and the two stage method to determine and refine crystal structures from powder diffraction data. pp 41–48 (Springer-Verlag Berlin Heidelberg, Germany, 2006).

Robert E. Dinnebier, Andreas Leineweber and John S.O. Evans. Rietveld Refinement: Practical Powder Diffraction Pattern Analysis using TOPAS (de Gruyter, 2019).

BRUKER AXS GmbH, Karlsruhe. “Diffrac plus TOPAS v. 3.0 (Manual, 2006).

J.D. Hanawalt, H.W. Rinn and L.K. Frevel, Chemical analysis by X-ray diffraction, Ind. Eng. Chem, Anal. Ed. 10 (1938) 457–513.

International center for diffraction data (ICDD), Inorganic crystal structure database (ICSD). https://www.icdd.com/

T. Ida, M. Ando and H. Toraya. Extended Pseudo-Voigt Function for Approximating the Voigt Profile, J. Appl. Cryst. 33 (2000) 1311–1316.

P. Bala, B.K. Samantaray, and S.K. Srivastava. Dehydration transformation in Ca-montmorillonite. Bull. Mater. Sci. Vol. 23:1 (2000) 61–67.

J. Garcia Guinea, V. Correcher and F.J. Valle-Fuentes. Thermoluminescence of Kaolinite. Radiation Protection Dosimetry, Vol. 84: 1–4 (1999) 507–510. https://doi.org/10.1093/oxfordjournals.rpd.a032787

G. Odriozola, J.F. Aguilar. Stability of Ca-montmorillonite hydrates: A computer simulation study, J. Chem. Phys., Vol. 123:17 (2005) 174708. https://doi.org/10.1063/1.2087447.

Downloads

Published

2021-11-01