O GRUPO PASSA DOIS (FORMAÇÕES CORUMBATAÍ E ESTRADA NOVA) NO ESTADO DE SÃO PAULO, BRASIL: FONTE DE MATÉRIA PRIMA PARA A INDÚSTRIA CERÂMICA

The Passa Dois Group (Corumbataí and Estrada Nova Formations) in the State of São Paulo, Brazil: source of raw material for the ceramic industry

Abstract

Studies show the clayey rocks of the Passa Dois Group, including Corumbataí and Estrada Nova formations, and excluding Irati formation- Permian of Paraná sedimentary basin, present variations in their geological and ceramic technological properties along their occurrence strip in the State of Sao Paulo. These variations are related from different sedimentary facies to diagenetic modification processes and hydrothermal and tectonic events during post depositional evolution. In the Santa Gertrudes Ceramic Pole, in the central São Paulo State, Brazil, the Corumbataí Fm. clays supply the wall and floor ceramic tiles industry as the main raw material. In addition, in the Porto Ferreira/Tambau and Laranjal Paulista/Cesário Lange poles, located less than 100 km far from Santa Gertrudes, Corumbatai clays are mainly used to manufacture structural ceramic products. The main difference between these clays is the higher presence of Na₂O in the Santa Gertrudes pole, due to de presence of albite in clays, which given to these material an important fluxing role in the ceramic sintering process. This fact allows the local industries to manufacture a huge amount of floor and wall ceramic tiles by using dry route making process, mainly classified as semi porous type (Water Absorption Group BIIb, according to Brazilian and worldwide ceramic tile classification). In the poles of Tambau/Porto Ferreira and Laranjal Paulista/Cesário Lange, according to the ceramic results obtained, the majority of the samples were classified as a porous material (Group BIII). It should be noted that the different lithofacies found in the rocks of the Passa Dois Group allow them to be used not only for the production of structural ceramics and semi-porous and porous ceramic plates, but also in the updating of masses in the production of porcelain and stoneware.