Experimental characterization of iron mining tailings as sustainable material for thermal energy storage

Abstract Mine tailings are an unavoidable waste generated during iron ore mining operations, of which millions of tonnes are generated worldwide. Given the importance of steel, and therefore, iron ore mining, solutions are needed to recover this waste. Despite global efforts, the current proposed solutions struggle to reach the market due to cost-effectiveness issues. This study explores a potential solution, presenting iron tailings as a viable, economical, and sustainable material for thermal energy storage systems. Thermal characterization showed a specific heat capacity of 780–990 J/kg·K up to 590 °C. The material remained thermally stable without melting or decomposition up to 1000 °C, and the resulting storage density was estimated up to 450 kWh/m3. The material stands up safety, minimal environmental impact, and favourable thermophysical properties at a low investment cost. This innovative application not only addresses energy challenges but also contributes to resolving the waste management crisis in the iron mining industry.