Quartz and feldspar-blended clay composites for thermal and structural applications

Abstract

In this study, some selected clay samples were beneficiated and blended with quartz and feldspar in various proportions to develop composites with good thermal and structural performance for sustainable development. X-ray fluorescence (XRF) analysis affirms the aluminosilicate nature of the clay samples and other trace oxides. The pore volume of the fired bulk composites disappears at 1200 °C leading to a decline in apparent density, apparent porosity, and water absorption. Furthermore, this study revealed that at the same temperature, the bulk density (1.69, g/cm³, 1.78, g/cm³, 1.78 g/cm³), modulus of rupture (33.2 kg/cm³, 39.34 kg/cm³, 38.88 kg/cm³), and total shrinkage (23.6 %, 22.3 %, 20.6 %) were maximum. Additionally, the results showed that the relative plasticity of the clay samples improved with the addition of feldspar and quartz from 1.27 to 1.33 and 1.35 for the fired composites (BO1: 50 % clay, 30 % feldspar, 20 % quartz, and CO1: 50 % clay, 25 % feldspar, 25 % quartz), respectively. Results obtained from thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis confirmed the clay samples to be thermally stable. The X-ray diffraction (XRD) patterns of all the fired composites showed major peaks, with quartz content being the highest at 27.5° (2θ) angle, albite presenting the lowest non-clay mineral content. Based on the analyses conducted in this study, it could be inferred that the clay sample is suitable for thermal insulation and structural applications.