2026-09-15 ペンシルベニア州立大学（Penn State）
＜関連情報＞
- https://www.psu.edu/news/earth-and-mineral-sciences/story/can-steelmaking-waste-help-solar-power-store-energy
- https://www.sciencedirect.com/science/article/abs/pii/S0038092X26005542
高温熱エネルギー貯蔵用途向け製鋼スラグの物理化学的特性および熱安定性の比較スクリーニング Comparative physicochemical and thermal stability screening of steelmaking slags for high-temperature thermal energy storage applications
Michael Enemuo, Arash Dahi Taleghani, Olumide Ogunmodimu
Solar Energy Available online 15 July 2026
DOI:https://doi.org/10.1016/j.solener.2026.114865
Highlights
- Characterized LMF, BOF, and EAF slags for high-temperature thermal energy storage.
- EAF slag showed the best thermal stability and lowest mass loss up to 800 °C.
- LMF slag showed moderate suitability but may require pre-conditioning before use.
- BOF slag had the lowest thermal stability due to free CaO and carbonate decomposition.
- Overall TES suitability followed the order EAF > LMF > BOF.
Abstract
The intermittency of renewable energy sources has intensified the demand for cost-effective, high-temperature thermal energy storage (TES) materials. Industrial steel slags — abundant by-products of steelmaking — represent a compelling sustainable alternative to conventional storage media such as molten salts. This study presents a systematic comparative physicochemical and thermal stability screening of three industrially sourced steel slags — Ladle Metallurgy Furnace (LMF), Basic Oxygen Furnace (BOF), and Electric Arc Furnace (EAF) — to evaluate their preliminary suitability as candidate materials for high-temperature TES applications. A multi-technique analytical framework was employed, integrating X-ray fluorescence (XRF), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS), thermogravimetric analysis with derivative thermogravimetry (TGA/DTG), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). All three slags are predominantly composed of Fe2O3, CaO, and SiO2, collectively accounting for approximately 70–88 wt% of the oxide content. This oxide profile suggests potential relevance to high-temperature TES screening, as Fe-, Ca-, and Si-bearing phases can contribute to phase stability, heat-storage potential, and potential thermal transport pathways. EAF slag exhibited the lowest total mass loss, approximately 0.9–1.0 wt% up to 800°C, together with a comparatively stable crystalline framework characterized by minimal detectable free lime, a belite–magnetite–RO phase assemblage, and a dense Fe-rich microstructure. These features indicate that EAF slag is a promising candidate for further evaluation as a high-temperature TES medium. LMF slag showed intermediate thermal stability, with a total mass loss of approximately 1.8–1.9 wt%, while BOF slag exhibited the highest mass loss, approximately 3.4–3.5 wt%, associated with portlandite, carbonate phases, and free-lime-related instability risks. Based on the indirect physicochemical and thermal stability indicators evaluated in this work, the preliminary TES suitability ranking is EAF > LMF > BOF. However, direct measurements of thermal conductivity, specific heat capacity, density, and long-term cyclic stability are required before definitive conclusions can be drawn regarding practical TES performance.
