摘要
铀尾矿库体积庞大、铀矿渣颗粒松散,具有潜在的溃坝和放射性污染扩散的风险。为了解决上述问题,采用Ca(OH)_(2)注浆与氢氧化钠-偏高岭土-水玻璃相结合的方法固化花岗岩型铀尾矿,研究注入不同质量分数的Ca(OH)_(2)对碱激发固化花岗岩型铀尾矿渣抗压强度、铀浸出性、氡析出性的影响规律,并进行微观形貌和理化分析,揭示其固化机制。实验结果表明:铀矿渣样品在注入Ca(OH)_(2)质量分数为15.0%,养护28天时其标准三轴抗压强度达到6.8MPa,与未注入Ca(OH)_(2)的样品相比强度提升4.4倍,铀浸出率下降89%,氡析出率降低52%。SEM和XRD分析表明,注入Ca(OH)_(2)质量分数为15.0%的试样与对照组试样相比,其内部形成了较多的C-S-H和C-A-H凝胶以及C-A-S-H聚合物,促进了铀尾矿渣固化抗压强度的提升,降低了铀浸出率和氡析出率。研究结果为碱激发在花岗岩型铀尾矿渣加固中应用奠定一定的理论基础。
The uranium tailings pond has a large volume and loose uranium tailing slags,which pose the risk of dam failure and diffusion of radioactive contamination.To address these issues,Ca(OH)_(2) grouting combined with sodium hydroxide and metacolinite-water glass was utilized to solidify granite-type uranium tailing slags.The impact of injected Ca(OH)_(2) mass fraction on the compressive strength,uranium leaching and radon exhalation of alkali-activated granite-type uranium tailings was investigated through microscopic morphology and physical and chemical analysis.Additionally,the solidification mechanism was elucidated.The experimental results showed that when the uranium slag was injected with 15.0%Ca(OH)_(2),the standard triaxial compressive strength reached 6.8MPa after curing for 28d,which was a significant improvement of 4.4 times compared to the sample without Ca(OH)_(2) injection.Additionally,adding Ca(OH)_(2) reduced uranium leaching rate by 89%and radon exfiltration rate by 52%.SEM and XRD analysis indicated that compared with the control group,more gels of C-S-H and C-A-H and polymers of C-A-S-H were formed in the sample with Ca(OH)_(2) mass fraction of 15.0%,which was the dominent reason for the improvement of compressive strength of solidified uranium tailing slags and the decrease of uranium leaching and radon exhalation.The research results laid a theoretical foundation for the application of alkali excitation in the reinforcement of granite-type uranium tailing slags.
作者
牛前进
李春光
刘振中
刘龙成
NIU Qianjin;LI Chunguang;LIU Zhenzhong;LIU Longcheng(School of Resource Environment and Safety Engineering,University of South China,Hengyang 421001,Hunan,China;R&D Center of Radioactive Waste Treatment,Disposal and Modeling,University of South China,Hengyang 421001,Hunan,China;China Institute of Atomic Energy,Beijing 102413,China;Beijing Institute of Chemical and Metallurgy for Nuclear Industry,Beijing 101121,China)
出处
《化工进展》
EI
CAS
CSCD
北大核心
2024年第11期6458-6467,共10页
Chemical Industry and Engineering Progress
基金
湖南省自然科学基金(2019JJ50496)
湖南省教育厅科学研究优秀青年项目(20B494)。
关键词
铀尾矿渣
污染
凝胶
碱激发
固定化
铀浸出率
氡析出率
uranium tailing slags
contamination
gels
alkali-activation
immobilization
uranium leaching rate
radon exhalation rate
作者简介
第一作者:牛前进(1989—),男,硕士,研究方向为铀资源与环境。E-mail:1414239706@qq.com;通信作者:李春光,副教授,硕士生导师,研究方向为核燃料循环化工与环境。E-mail:lichunguang1983@163.com。
