Substituição total ou parcial do feldspato por filito em massas cerâmicas para produção de porcelanatos

Abstract

Porcelain tile stands out among ceramic coverings due to its high technical performance, directly associated with a high degree of sintering and low porosity, producing products with high density and low water absorption. Feldspar has historically been one of the main raw materials used in the composition of porcelain tile bodies, aiming to provide fluxing oxides, and its high consumption has impacted supply and, consequently, increased production costs. Therefore, it is necessary to search for alternatives that aim to totally or partially replace the use of feldspar in ceramic bodies. In this context, this work evaluates the total or partial replacement of feldspar with phyllite from the Lagarto region (SE) in glazed porcelain tile bodies, aiming to meet the requirements of the ABNT NBR ISO 13006:2020 standard. Five compositions were formulated containing 0%; 25%; 50%; 75% and 100% phyllite in relation to feldspar. Specimens of each formulation were fired between 1,155 °C and 1,190 °C, in 5 °C increments. The physicochemical properties of water absorption, linear firing shrinkage, pyroplasticity index, and flexural strength were evaluated. The results indicated an increase in water absorption and a reduction in linear firing shrinkage with increasing phyllite, highlighting the more refractory character of the raw material. The formulation with 100% phyllite achieved water absorption below 0.5% at 1,180 °C, while the composition with 0% phyllite reached this value at 1,175 °C. It is concluded that phyllite can partially or totally replace feldspar in porcelain tile bodies, maintaining properties compatible with normative parameters, in addition to representing an economically advantageous alternative for the ceramic industry.