Preliminary investigation on the characterization and recycling of elephant grass ash waste for potential application in siliceous porcelain

Brazil produces a large amount of elephant grass ash waste from burning elephant grass biomass as a renewable energy source. An issue of great technological importance is to find a viable application for the valorization of this solid waste. This study addresses the possibility of recycling of elephant grass ash waste as an alternative raw material in the production of siliceous porcelain. The chemical characterization of the elephant grass ash waste was carried out using the X-ray fluorescence, differential thermal analysis and thermogravimetric analysis techniques. Siliceous porcelain formulations incorporated with up to 5 wt.% of elephant grass ash waste for partial replacing quartz were prepared. The siliceous porcelain pieces were manufactured by pressing and fired at 1300 °C. The effect of elephant grass ash waste on the siliceous porcelain was evaluated by monitoring water absorption, linear shrinkage, apparent porosity, and apparent density. The elephant grass ash waste was composed primarily of silicon oxide (SiO2), but also contained appreciable amounts of fluxing oxides (S CaO + MgO + K2O + Na2O). The results indicated that siliceous porcelain incorporated with up to 5 wt.% of elephant grass ash waste showed good technical properties in terms of water absorption (0.12 - 0.14 %) and apparent density (2.41 - 2.45 g/cm3). These findings indicate that elephant grass ash waste has great potential to be recycled in the production of siliceous porcelain.