Sustainable use of tannery lime yard ground in roof tile: waste-to-wealth approach

In the tannery at a beamhouse, a large amount of tannery lime yard ground (TLYG) is emitted, which affects the environment. Worldwide, the tanning industry is facing a significant issue in managing the large amount of TLYG. The fabrication of roof tiles incorporating TLYG to replace clay has emerged as a promising strategy. The physicomechanical properties of the roof tiles that were produced are comparable to those of traditional clay roof tiles. In this study, an approach was developed to partially replace clay with TLYG in high-quality roof tile production. The clay of the roof tiles was replaced with TLYG at various ratios of 0% to 15% (wt.) and burned at 1000 °C in the kiln. The physicomechanical properties of the burned TLYG-clay-incorporated roof tiles were evaluated. Surface morphology was observed by scanning electron microscopy (SEM). Metal elements and chemical composition were analyzed through energy dispersive spectroscopy (EDS) and X-ray fluorescence (XRF) spectrophotometer analysis. XRF data revealed a significant amount of CaO (38.14%) and SO₃ (25.36%), which are attributed to the blockage of pores enhancing the strength of the roof tiles. Results reveal that, with 8% TLYG-incorporated roof tiles, weight loss on ignition, area shrinkage, water absorption, bulk density, compressive strength, and breaking strength were achieved at 11.0%, 6.6%, 11.1%, 1.7 g/cm³, 48.3 MPa, and 3160.0 N, respectively. The breaking strength of 8% TLYG-clay-incorporated roof tile satisfied the type. No salt deposition on the surface of up to 11% TLYG-incorporated roof tile was observed. The prepared 8% TLYG-incorporated roof tiles were comparable to the control and met all standard requirements. The cost-effectiveness of 8% TLYG-incorporated roof tiles provides further impetus for replacing the traditional tiles. Consequently, the proposed method can significantly utilize TLYG in roof tile preparation as a waste-to-wealth approach.