Environmentally safe solid waste–derived dark ceramics with Mn3+/Mn4+ double-exchange for enhanced NIR reflectivity
Wang J. An C. Li Q. Liu B. Zhang X. Zhang D. Zhang S.
April 2026Elsevier Ltd
Journal of Environmental Chemical Engineering
2026#14Issue 2
This study developed environmentally safe dark near-infrared (NIR) reflective ceramics from silico-manganese slag, copper slag, and magnesium slag by reproducing a Ca-Mn-Fe solid solution mechanism established in a chemically pure model system. X-ray diffraction following the reference intensity ratio method and scanning electron microscopy confirmed the formation of Ca3Mn1.2Fe1.8O8, where the content increased from 16.1 to 43.1 wt% with higher Mn/Fe input, accompanied by NIR reflectance (700–2500 nm) of 50.09–59.25 % and NIR solar reflectance (R*) up to 45.77 %, comparable to the model composition (R* ≈ 48.89 %). The Mn3+/Mn4+ mixed valence and Mn3+-O-Mn4+ double-exchange interactions narrowed the effective bandgap to ∼ 1.6 eV and enhanced carrier-induced NIR reflection, enabling a dark appearance with high NIR reflectivity. Toxicity leaching tests showed Cr(VI), Mn, Ni, Cu, and As concentrations below 0.004, 0.17, 0.03, 0.01, and 0.03 mg/L, respectively, far lower than the GB 8978-1996 limits, confirming the reliable immobilization of hazardous elements. Thermal irradiation tests demonstrated that the optimal waste-derived sample achieved a 6.3 °C lower equilibrium temperature than commercial iron black pigment after 60 min under a 100-W NIR lamp, demonstrating its practical cooling potential. These results established a mechanism-guided route to convert multisource industrial slag materials into structurally dense, environmentally safe black ceramics with high NIR reflectivity for energy-saving architectural applications. Copyright
Copper slag , Energy saving , Near-infrared reflectivity , Silicomanganese alloy slag , Utilization of resources
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Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing, 100083, China
School of Physics and Materials Science, Nanchang University, Jiangxi, Nanchang, 330031, China
Xinjiang Research Institute for Nonferrous Metals Co., Ltd., Urumqi, 830009, China
Department of Civil and Environmental Engineering, School of Engineering and Digital Sciences, Nazarbayev University, Astana, Kazakhstan
Institute for Advanced Materials and Technology
School of Physics and Materials Science
Xinjiang Research Institute for Nonferrous Metals Co.
Department of Civil and Environmental Engineering
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