Redução da susceptibilidade à deformação piroplástica das argilas do Pólo Cerâmico de Santa Gertrudes através da adição de matérias-primas
Carregando...
Data
2008-03-01
Autores
Prado, A. C. A. [UNESP]
Zanardo, A. [UNESP]
Moreno, M. M. T.
Menegazzo, A. P. M.
Título da Revista
ISSN da Revista
Título de Volume
Editor
Associação Brasileira de Cerâmica
Resumo
A maioria das fábricas do Pólo de Santa Gertrudes usa as argilas desta região como única matéria-prima para a fabricação do suporte de revestimento BIIb. Estas argilas são compostas de uma forma geral por illita, albita, quartzo, hematita e em níveis localizados por carbonatos. Illita, hematita e carbonatos aumentam a susceptibilidade à super-queima e à deformação piroplástica. Esta susceptibilidade foi medida através de diagramas de gresificação. Foram testadas as seguintes amostras: perfil de uma mina (C); nível mais albítico desta mina (CV); misturas contendo CV e caulim; CV mais alumina; CV com feldspato potássico; CV com diabásio; CV mais caulim, feldspato e quartzo; CV mais diabásio e caulim; e uma massa industrial de porcelanato. As propriedades de CV variaram menos com a temperatura do que as de C. A adição de diabásio, alumina e feldspato potássico não alterou significantemente a inclinação das curvas de gresificação. A adição de caulim reduziu consideravelmente a susceptibilidade à super-queima e à deformação piroplástica, tendendo à estabilidade dimensional da massa de porcelanato. As variações da absorção e da retração com a temperatura foram menores na mistura que continha CV mais caulim, feldspato e quartzo, porém as peças dessa mistura ficaram frágeis. A massa composta por CV, diabásio e caulim também apresentou menor susceptibilidade à super-queima e à deformação piroplástica.
The majority of Santa Gertrudes region plants use the Corumbataí Formation material as the only raw material for BIIb ceramic tiles manufacture. The formation generally is composed by illite, albite, quartz, hematite and in specific beds by carbonates. The production of low porosity tiles is intricate mainly due to the larger occurrence of dimensional instability problems caused by over firing and pyroplastic deformation. Illite, hematite and carbonates increase susceptibility to these phenomena. This susceptibility was measured through vitrification diagrams. The influence of other raw materials over a feldspar rich lithotype of Corumbataí Formation was analyzed. The following samples were tested: a mine s outline (C), the more albitic level of this mine (CV), CV and Kaolin-bearing mixtures, CV plus alumina, K-Feldspar bearing CV, CV with diabase, CV plus kaolin/feldspar/quartz, CV plus diabase and kaolin. CV is less sensitivity to temperature variability than C. The addiction of diabase, alumina and K-feldspar did not increase dimensional stability. Kaolin s addition considerably decreased the susceptibility to over firing and to pyroplastic deformation. The absorption water and linear shrinkage s variability with temperature of specimens with CV, kaolin, feldspar and quartz were small, but the mechanical resistance decreased. The CV-kaolin-diabase composition decreased the susceptibility of pyroplastic deformation.
The majority of Santa Gertrudes region plants use the Corumbataí Formation material as the only raw material for BIIb ceramic tiles manufacture. The formation generally is composed by illite, albite, quartz, hematite and in specific beds by carbonates. The production of low porosity tiles is intricate mainly due to the larger occurrence of dimensional instability problems caused by over firing and pyroplastic deformation. Illite, hematite and carbonates increase susceptibility to these phenomena. This susceptibility was measured through vitrification diagrams. The influence of other raw materials over a feldspar rich lithotype of Corumbataí Formation was analyzed. The following samples were tested: a mine s outline (C), the more albitic level of this mine (CV), CV and Kaolin-bearing mixtures, CV plus alumina, K-Feldspar bearing CV, CV with diabase, CV plus kaolin/feldspar/quartz, CV plus diabase and kaolin. CV is less sensitivity to temperature variability than C. The addiction of diabase, alumina and K-feldspar did not increase dimensional stability. Kaolin s addition considerably decreased the susceptibility to over firing and to pyroplastic deformation. The absorption water and linear shrinkage s variability with temperature of specimens with CV, kaolin, feldspar and quartz were small, but the mechanical resistance decreased. The CV-kaolin-diabase composition decreased the susceptibility of pyroplastic deformation.
Descrição
Palavras-chave
placas cerâmicas para revestimento, argilas vermelhas, Formação Corumbataí, grés, porcelanato, diagrama de gresificação, ceramic tiles, red clays, Corumbataí Formation, stoneware, porcelain stoneware, vitrification diagram
Como citar
Cerâmica. Associação Brasileira de Cerâmica, v. 54, n. 329, p. 7-20, 2008.