Bulletin of the Chinese Ceramic Society, Volume. 41, Issue 1, 182(2022)
Properties and Mechanism of Solidification of Simulated Radioactive Incineration Ash with Low Alkalinity Cement-Based Materials
The existence of metallic aluminum in the radioactive incineration ash results in the expansion and deterioration of cement waste forms, due to the reaction of metallic aluminum with high alkali pore solution to produce hydrogen gas in hardened Portland cement or alkali-activated cementitious materials. In this study, low alkalinity cement-based materials were prepared by Portland cement, silica fume and fly ash as the main raw materials, aiming to overcome this problem. Zeolite, polycarboxylate superplasticizer, diutan gum and polyaluminum sulfate were used as well to modify the properties. According to the results, 28 d compressive strength of over 16.6 MPa is achieved by low alkalinity cement-based materials waste forms with 30% (in mass) simulated radioactive incineration ash. The freeze-thaw resistance, immersion resistance and impact resistance meet the requirements of GB 14569.1—2011 specifications. The leaching rate of Ce3+ on the 42 d is 4.41×10-9 cm/d, and the cumulative leaching fraction is 3.4×10-7 cm. The relatively lower pH value of pore solution in the early age and high Ca concentration in pore solution hinders the reaction between the metallic Al and pore solution. At later age, no reaction between metallic Al and pore solution because the pH value of pore solution is below 11.75.
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WEI Qi, GENG Haining, MA Haosen, LIU Yan, CHEN Wei, WANG Dongwen, PAN Sheqi, LI Qiu. Properties and Mechanism of Solidification of Simulated Radioactive Incineration Ash with Low Alkalinity Cement-Based Materials[J]. Bulletin of the Chinese Ceramic Society, 2022, 41(1): 182
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Received: Aug. 26, 2021
Accepted: --
Published Online: Aug. 4, 2022
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CSTR:32186.14.