A Desktop Study on the Potential Use of South African Slags as Thermal Storage Medium

Abstract

Waste slag sources from South African pyrometallurgical smelters are evaluated to determine their potential for use as sensible heat storage media in Concentrated Solar Power applications. This offers the possibility of repurposing slag waste materials while tackling their environmental and handling problem. This work studies the key performance indicators of thermal energy storage systems to assess the suitability of pyrometallurgical slag for use as filling materials in packed bed thermal energy storage. The thermophysical properties of selected slags and their potential for long-term thermal stability is studied through the equilibrium module of FactSage 8.0 from 100 to 1000 °C. A validated model is employed to study the heat transport process in the fluid–solid interface with air as the heat transfer fluid. The maximum temperature of the studied thermal storage cycles is 750 °C. The overall system performance shows that pyrometallurgical slags have potential as energy storage materials.