低碱度水泥基材料固化模拟放射性焚烧灰性能与机理研究  

Properties and Mechanism of Solidification of Simulated Radioactive Incineration Ash with Low Alkalinity Cement-Based Materials

作　　者：韦琦 耿海宁[3] 马浩森 刘艳[4] 陈伟[1] 王东文[4] 潘社奇[4] 李秋[1] WEI Qi;GENG Haining;MA Haosen;LIU Yan;CHEN Wei;WANG Dongwen;PAN Sheqi;LI Qiu(State Key Laboratory of Silicate Materials for Architectures,Wuhan University of Technology,Wuhan 430070,China;School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China;Hubei Urban Construction Vocational and Technological College,Wuhan 430205,China;Institute of Materials,China Academy of Engineering Physics,Mianyang 621907,China)

机构地区：[1]武汉理工大学硅酸盐建筑材料国家重点实验室,武汉430070 [2]武汉理工大学材料科学与工程学院,武汉430070 [3]湖北城市建设职业技术学院,武汉430205 [4]中国工程物理研究院材料研究所,绵阳621907

出　　处：《硅酸盐通报》2022年第1期182-191,共10页Bulletin of the Chinese Ceramic Society

基　　金：国家自然科学基金面上项目(52072279);中国工程物理研究院横向科研项目;硅酸盐建筑材料国家重点实验室(武汉理工大学)开放基金(SYSJJ2021-12);深圳市科技计划项目协同创新专项(CJGJZD20200617102601003)。

摘　　要：放射性焚烧灰中存在铝单质金属,其在碱激发水泥或硅酸盐水泥的高碱性孔溶液环境下会反应产生氢气,造成固化体膨胀与性能劣化。为克服此问题,本研究以水泥、硅灰和粉煤灰为主要原料,添加沸石、聚羧酸减水剂、定优胶和聚合硫酸铝协同改性制备低碱度水泥基材料,开展低碱度水泥基材料对模拟放射性焚烧灰的固化处置研究。结果表明:模拟放射性焚烧灰质量包容量为30%的低碱度水泥基材料固化体的28 d抗压强度达16.6 MPa以上,抗冻融性能、抗浸泡性能及抗冲击性能均满足GB 14569.1—2011《低、中水平放射性废物固化体性能要求-水泥固化体》的要求。Ce^(3+)第42 d浸出率为4.41×10^(-9) cm/d,累计浸出分数为3.4×10^(-7) cm。低碱度水泥基材料固化模拟放射性焚烧灰过程中未产生大量氢气,其原因是,在早期孔溶液pH值较低,同时孔溶液中的高钙离子浓度延缓了焚烧灰中的单质铝与孔溶液发生反应释放氢气的速度,在后期孔溶液pH值低于11.75,焚烧灰中的单质铝不会与孔溶液发生反应。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 Ce^(3+)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.

关 键 词：固废处置 水泥基材料 低碱度 放射性焚烧灰 单质金属 固化 浸出率 累积浸出分数 

分 类 号：TL941[核科学技术—辐射防护及环境保护]