Effects of granite waste addition on the technological properties of industrial silicate based-ceramics

Abstract

Granite waste has been studied as an eco-friendly raw material in red clay processed-ceramics. However, its influence on the technological properties of industrial porcelain tile formulations has been little discussed, which leaves gaps in this field. This work aims to understand the effects of granite waste content on the physico-mechanical properties of silicate based-ceramics (red clay and porcelain tile). Starting materials were characterized by x-ray fluorescence (XRF), x-ray diffractometry (XRD), particle size distribution, and thermal analyses (DTA and TG). The effects of granite waste addition on the technological properties of sintered samples were evaluated by measuring water absorption, apparent density, and flexural strength. XRD pattern revealed that the granite waste consists of quartz, muscovite, potassium feldspar, anorthite, cordierite, calcite, and dolomite, which is similar to that of raw materials used in the ceramic industry. The characterization of the raw materials showed that granite waste is a promising material to be used in the ceramic industry, without impairing mechanical strength of porcelain tile for additions of up to 12 wt%. This study reports a high mechanical strength of 40 MPa for samples with 3 wt% waste content sintered at 1150 °C. Granite waste additions showed values of water absorption (<18.3%, for samples with up to 50 wt% granite waste content) and flexural strength (>7.3 MPa, for samples with up to 38 wtwt% granite waste) in good agreement with the range established by the Brazilian standard for perforated bricks and roof tiles.