Addition of sedimentary rock to kaolinitic clays: influence on sintering process

• Autor(a) principal: Souza,A. E.
• Data de Publicação: 2013
• Outros Autores: Teixeira,S. R., Santos,G. T. A., Longo,E.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Cerâmica (São Paulo. Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0366-69132013000100017
• topic: clay; sedimentary rock; fluxes; sintering; mullite

The physical and mechanical properties of clay-based ceramic probes with sedimentary rock added as the non-plastic component were evaluated. Samples were prepared with 0, 20, 40, 60 and 80 wt.% of rock added to the clay material. Pressed (7 ton) probes were sintered at 500, 800, 900, 1000, 1100 and 1200 °C and submitted to X-ray diffraction analysis and technological characterization. The X-ray diffraction results showed that the sedimentary rock had micaceous clay minerals, while the clay material had kaolinite as the main phases. Thermal analysis and X-ray diffraction showed reactions that indicated transformation (inversion of quartz), decomposition (loss of hydroxides) and phase formation (mullite) during heat treatment of the samples. The technological tests showed that the addition of sedimentary rock improved some properties of the sintered material, aided by the presence of fluxes. However, the presence of quartz in the rock hampered the formation of the mullite phase. The formation of new phases and transformations occurring during the heating and cooling of the samples helped explain the technological properties of ceramic materials.