Selective Extraction and Coprecipitation Strategy for Effective Removal of 137 Cs and Heavy Metals from Radioactive Electric Arc Furnace Dust Leachates

The rising demand for steel has led to a rise in steel waste, including electric arc furnace dust (EAFD), which contains various heavy metals and may be contaminated with radioactive cesium-137 (137Cs). Owing to 137Cs’ long half-life and strong gamma radiation, improper management of 137Cs-contaminated EAFD poses serious environmental and health risks. This study examined an integrated extraction and precipitation method for the large-scale removal of 137Cs from EAFD using various solvents and chemical agents. Radioactive EAFD particles with an initial activity of 3.28 (low) and 280 Bq/g (high) were extracted using tap water and 1.0M H2SO4, at a liquid-to-solid ratio of 1:2, and the sample mass was scaled from 5 to 5 kg. The resulting waste solutions were decontaminated using 0.01M K4[Fe(CN)6], with Al2(SO4)3 employed as a coagulation promoter. The results showed that 1.0 M H2SO4 was more effective than tap water, yielding approximately 22% higher 137Cs removal efficiency. Furthermore, the extraction process released metallic elements such as Al, Cd, and Cr, with removal efficiencies exceeding 99%. The addition of Al2(SO4)3 enhanced 137Cs removal from the waste solution by 22.6% compared to precipitation without a promoter, likely due to improved coagulation. Importantly, scaling up the process had no significant impact on extraction efficiency, indicating its feasibility for larger operations. The key advantage of this study is the integration of extraction and precipitation for effective large-scale 137Cs decontamination from EAFD. Overall, 1.0M H2SO4 combined with Al2(SO4)3 presents a promising approach for the efficient removal of radioactive cesium and heavy metals from EAFD.