Application of metakaolin based polymer in the treatment of low level radioactive waste liquid
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CHENG Jianfeng,male,born in 1989,PhD,focusing on the environmental chemistry of geological disposal of high-level radioactive waste. E-mail:jfeng_cheng@163.com |
Received date: 2024-12-25
Revised date: 2025-01-23
Online published: 2025-11-07
Supported by
National Key R&D Program of China(2022YFE0120500)
The development of nuclear energy is inseparable from the treatment and disposal of radioactive waste. Geopolymer is a promising radioactive waste solidification material. In this study,metakaolin was used as the substrate to prepare metakaolin polymer, which was used to solidify Cs and real radioactive waste. The properties of metakaolin geopolymer were investigated by characterization and leaching experiments. Characterization experiments show that metakaolin geopolymer with three-dimensional network structure has high compressive strength, which can meet the strength requirements of radioactive waste solidified body. At the same time, the solidification of Cs in metakaolin polymer is uniform. However, the incorporation of Cs will hinder the growth of silicon and aluminum network skeleton and reduce the gel structure of the system,resulting in the increase of porosity and the decrease of compressive strength of geopolymer cured body. The leaching experiments of Cs and real waste water in deionized water and real groundwater show that metakaolin polymer has excellent Cs retention ability,and has low leaching rate and cumulative leaching fraction,which is better than the value specified in the national standard. In general,metakaolin geopolymer performs well in physical compression resistance and Cs retention,and is a material with great application potential.
Jianfeng CHENG , Qi ZHANG , Zihua ZONG , Yanhui DONG , Shengfei CAO , Liyuan PENG . Application of metakaolin based polymer in the treatment of low level radioactive waste liquid[J]. World Nuclear Geoscience, 2025 , 42(1) : 123 -133 . DOI: 10.3969/j.issn.1672-0636.2025.01.010
表2 某厂低水平放射性废液成分表Table 2 Composition of low level radioactive waste liquid of a plant |
| 密度/(g·cm-3) | pH | 含盐量/(g·L-1) | 初始比活度/(Bq·L-1) | ||
|---|---|---|---|---|---|
| 137Cs | 241Am | Σβ | |||
| 1.13 | 7.45 | 297 | 3.13×104 | 3.13×101 | 3.42×104 |
图2 不同Cs掺量偏高岭土基地聚合物在不同时间的抗压强度Fig. 2 Compressive strength of metakaolin base polymer with different Cs content at different times |
表3 不同Cs掺量偏高岭土基地聚合物在不同时间的抗压强度Table 3 Compressive strength of metakaolin base polymers with different Cs contents at different times |
| Cs+含量/wt% | 3 d抗压强度/MPa | 7 d抗压强度/MPa | 14 d抗压强度/MPa | 28 d抗压强度/MPa |
|---|---|---|---|---|
| 0 | 34.18 | 57.08 | 62.52 | 65.47 |
| 1 | 31.54 | 45.33 | 53.78 | 61.04 |
| 5 | 28.28 | 42.26 | 43.82 | 50.13 |
| 10 | 23.58 | 34.31 | 40.07 | 41.08 |
图7 不同Cs掺量偏高岭土基地聚合物在去离子水中的浸出率(a)和累积浸出分数(b)Fig. 7 Leaching rate (a) and cumulative leaching fraction (b) of metakaolin based polymers with different Cs contents in deionized water |
表4 水泥及地聚合物累积浸出分数比较Table 4 Comparison of cumulative leaching fractions of cement and geopolymer |
| 样品 | 尺寸 | 最大累积浸出分数 | 参考文献 | |
|---|---|---|---|---|
| 本实验 | 偏高岭土基地聚合物 | 40 mm×40 mm×40 mm | 1.70×10-2 cm | |
| 水泥 | 普通硅酸盐水泥 | 20 mm×20 mm×20 mm | 1.28×10-1 cm | [39] |
| 普通硅酸盐水泥 | h = 40 mm, d = 40 mm | 1.66×10-1 cm | [40] | |
| 地质水泥 | 50 mm×50 mm×50 mm | 1.15×10-1 cm | [41] | |
| 磷酸镁水泥 | 20 mm×20 mm×20 mm | 7.01×10-2 cm | [42] | |
| 地聚合物 | 粉煤灰地聚合物 | 20 mm×20 mm×20 mm | 8.17×10-2 cm | [43] |
| 磷酸活化地聚合物 | 20 mm×20 mm×20 mm | 1.31×10-2 cm | [44] | |
| 粉煤灰地聚合物 | h = 25 mm,d = 50 mm | 2.03×10-2 cm | [45] | |
| 粉煤灰基沸石固化体 | 20 mm×20 mm×20 mm | 2.00×10-2 cm | [46] | |
| 粉煤灰地聚合物 | 20 mm×20 mm×20 mm | 2.87×10-2 cm | [47] |
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