Abstract This study investigates for optimizing thermal treatment conditions for the effective decontamination of cobalt(Co)-contaminated concrete waste. About 21 g of ordinary Portland cement (OPC, Type I), 37 g of dry sand, 5 g of fly ash, and 24 g of aggregates were mixed, cured for 28 days, and used for characterization and thermal treatment. Thermal treatment was conducted at different temperatures between 105 °C and 600 °C. The samples were characterized using SEM, XRD, FTIR, XRF, and XAS. Up to 600 °C, mass loss only occurred for water molecules in the concrete with ~60% volume reduction, suggesting an optimum temperature between 500 °C and 550 °C. During thermal treatment, Co phase changed from Co3O4 to CoO, and among the various chemical solutions, chloric acid exhibits the highest Co decontamination efficiency. The results suggest that a combination of thermal and chemical treatments can enhance Co removal from concrete waste.

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韩国核电站退役混凝土废物的净化

摘要 本研究旨在优化热处理条件，以有效净化钴 (Co) 污染的混凝土废物。将约21克普通硅酸盐水泥（OPC，I型）、37克干砂、5克粉煤灰和24克骨料混合，固化28天，用于表征和热处理。热处理在 105 °C 和 600 °C 之间的不同温度下进行。使用 SEM、XRD、FTIR、XRF 和 XAS 对样品进行表征。直到 600 °C，混凝土中的水分子才会发生质量损失，体积减少约 60%，这表明最佳温度在 500 °C 和 550 °C 之间。在热处理过程中，Co 相从 Co3O4 转变为 CoO，在各种化学溶液中，氯酸的 Co 去污效率最高。