In this work, the dense glass matrix of uranium tailings was successfully fabricated via microwave sintering process with Na₂CO₃ as a sintering aid. The effects of Na₂CO₃ additive and sintering temperature on the microstructure and mechanical properties of as-prepared solids were systematically investigated. XRD results confirmed the vitrified forms can be achieved at 1200°C within 30 min with 20 wt.% Na₂CO₃ addition. Importantly, the Na₂CO₃ additive significantly reduced the firing temperature from 1500°C to 1200°C and promoted densification. FT-IR analysis demonstrated that the main characteristic peaks of the sintered samples were attributed to the vibration of Si-O-Si. Microstructural studies presented the homogeneous distribution of glass phases. The results of mechanical properties of the sintered forms show that bulk density and Vickers hardness increased with increasing Na₂CO₃ content as well as sintering temperature, and the highest bulk density (2.45 ± 0.01 g/cm³) and Vickers hardness (823 ± 25 HV) were obtained at the temperature of 1300°C with 20 wt.% Na₂CO₃ addition, the heating rate of 20°C/min, and the soaking time of 30 min. It implied that the combination of microwave sintering with the appropriate addition of Na₂CO₃ would provide an efficient method for the immobilization of radionuclides in uranium tailings.

中文翻译：

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铀尾矿的微波玻璃化：组织和力学性能

在这项工作中，通过以Na ₂ CO ₃为烧结助剂的微波烧结工艺成功地制备了铀尾矿的致密玻璃基质。系统地研究了Na ₂ CO ₃添加剂和烧结温度对所制备固体的微观结构和力学性能的影响。XRD结果证实玻璃化形式可以在1200℃下在30分钟内通过添加20重量％的Na ₂ CO _3来实现。重要的是，Na ₂ CO ₃添加剂将烧成温度从1500°C显着降低到1200°C，并促进了致密化。FT-IR分析表明，烧结样品的主要特征峰归因于Si-O-Si的振动。微观结构研究表明玻璃相的均匀分布。烧结形式的力学性能结果表明，堆密度和维氏硬度随Na ₂ CO ₃含量和烧结温度的增加而增加，最高堆密度（2.45±0.01 g / cm ³）和维氏硬度（823±2）。在1300°C的温度下用20 wt。％Na ₂ CO ₃获得25 HV）另外，加热速度为20℃/ min，均热时间为30min。这暗示微波烧结与适当添加Na ₂ CO _3的组合将提供一种将放射性核素固定在铀尾矿中的有效方法。