Physico-chemical and thermal behavior of Barind red clay from Naogaon, Bangladesh: Implications for ceramic industries as a raw material

This study evaluates the potential industrial suitability of red clay from Sapahar Upazila, Naogaon District, Bangladesh. Comprehensive laboratory tests were conducted, including Atterberg limits, grain size analysis, X-ray diffraction (XRD), X-ray fluorescence (XRF), Scanning electron microscopy (SEM) and Thermogravimetric analysis (TG), to investigate the mineralogical, geological, ceramic, and plastic properties of the samples. The mineralogical analysis reveals that the red clay is composed of illite, kaolinite, montmorillonite and quartz. Chemically, the red clay primarily composed of SiO₂ (55.06–57.73 %), followed by Al₂O₃ (16.96–18.89 %), Fe 2 O 3 (8.29–10.15 %), K₂O (2.98–3.42 %), TiO 2 (1.28–1.38 %), trace amounts of other oxides (<1 %) and LOI (8.34 %-9.99 %). TG/DSC curve trends indicate the stability of red clay up to 900°C. Firing experiments conducted at 800°C, 900°C, 1000°C and 1100°C show changes in firing shrinkage (0.05 %-1.15 %), water absorption (7.66 %-4.31 %), apparent porosity (13.58 %-9.53 %), bulk density (1.77 g/cm 3 -2.21 g/cm³) and unconfined compressive strength (1.35–7.22 MPa). These findings suggest that the local red clay is suitable for manufacturing vitrified and semi-vitrified ceramic tiles, indicating its potential for industrial applications in the ceramics sector. Future studies should aim to upscale the experimental findings and comprehensively evaluate the performance of the clay under industrial production. • Barind red clay shows high SiO₂ (55–58 %) and Al₂O₃ (17–19 %) for ceramics. • Thermal stability confirmed beyond 1000°C via TG/DSC analysis. • Firing at 1100°C enhances density (2.21 g/cm³) and strength (7.22 MPa). • Low water absorption (4.31 %) meets ISO 13006 for vitrified tiles. • Mineralogy (illite, kaolinite) supports industrial ceramic production.