Leaching behavior and compressive strength in the immobilization of Cs-137 contaminated electric arc furnace dust via doping with activated carbon
Sudarat Issarapanacheewin, Dechanun Choomjun, Witsanu Katekaew, Nikom Prasertchiewchan, Wilasinee Kingkam
Abstract
This study evaluated the potential of an immobilization technique to inhibit the migration and dispersion of Cs-137 contaminated electric arc furnace dust (EAFD) into the environment, by investigating its compressive strength and leaching characteristics. The EAFD was employed to replace ordinary Portland cement (OPC) in varied ratios, ranging from 0 % to 50 % by weight. The replacement was done using various water-binder ratios of 0.35, 0.40, 0.45, and 0.50. Furthermore, the use of activated carbon (AC) has been shown to minimize radionuclide and heavy metal discharge related to its high porosity. AC was added at weight concentrations of 0.5 %, 1.0 %, 1.5 %, and 2.0 %. Compressive strength and leaching tests are used to assess the long-term stability of waste forms and the effectiveness of immobilizing radioactive wastes, which is beneficial for storing and disposing of radioactive waste. The compressive strength is affected by the amount of EAFD, water-to-binder ratios, the addition of AC, and the duration of curing. Measurements of specific surface area, pore size, pore volume, and porosity were also carried out under various conditions. The research results indicate that the addition of AC improves the compressive strength and decreases the release of Cs-137 and heavy metals from the specimen. The mixture of 45 % EAFD and 1.5 % AC is appropriate for efficiently immobilizing Cs-137 contaminated EAFD.