Assessment of Metallurgical Slags as Solar Heat Absorber Particles

Abstract

The use of ceramic solid particle technology in TES integrated CSP plants offers high solar to elec-tricity ratio and enhanced storage densities thanks to their high operational temperatures and wide temperature ranges. Metallurgical slags with similar composition to the state-of-art bauxite particles can be utilized as a sustainable and economical secondary raw material to prepare solid particles. In this study, as-received state and high temperature phase and microstructural changes of two fayalite slags from copper and lead recycling were elucidated by XRD and SEM/EDX methods in a comparative manner. Solid particles were prepared from slags by oil dropping method with subsequent heat treatment. Solar thermal application related functional properties of slag particles such as heat capacity, absorptance ad thermo physical properties were evaluated by DSC, spectrophotometer, heating microscope and high temperature compressive tests; respective-ly. Owing to the formation of more stable Fe-rich phase components and less amount of glassy phase, copper slag is found out as a more promising secondary resource than lead slag in terms of material and functional properties.