Computational simulations of structural defects produced during kaolinite dehydroxylation.

I. POLCOWÑUK IRIARTE; N. RENDTORFF; D. RICHARD

Revista del Museo de La Plata

FACULTAD DE CIENCIAS NATURALES Y MUSEO, UNIVERSIDAD NACIONAL DE LA PLATA

Lugar: La Plata; Año: 2023 vol. 8 p. 252 - 261

0372-4565

The importance of kaolinite in modern ceramic science becomes apparent when considering its influence onceramics, materials science, and mineralogy. Because the industrial uses of kaolinite require thermal treatments,there is interest in understanding the formation of metakaolin during the thermal activation of this clay, as wellas in knowing the physics and chemistry mechanisms behind its production. In this work we studied thebeginning of the dehydroxylation process using calculation methods based on Density Functional Theory. Inparticular, we proposed four systems that combine vacancies of an OH group and a H atom in the kaolinite unitcell. For each of these variants, we optimized the structure and analyzed the energy of the system afteroptimization. The results were compared between each other and with the literature. Finally, we studied thedensity of electronic states for the system most compatible with the start of the physical process ofdehydroxylation and compared it with that of kaolinite. These results contribute to investigate different modelsystems that could describe the beginning of the process for metakaolin production, as well as understand thedifferences between these systems.Keywords: Kaolin, Metakaolin, Simulations, Vacancies, Density functional theory