掺钕钙钛锆石基玻璃陶瓷制备及浸出性能研究

Preparation and Leaching Property of Nd-doped Zirconolite-based Glass-ceramic

  • 摘要: 采用熔融-热处理工艺制备了掺钕钙钛锆石基玻璃陶瓷,研究了不同热处理工艺对玻璃陶瓷晶相结构的影响,用粉末静态浸泡法(PCT法)对玻璃陶瓷的浸出性能进行了评价。结果表明,玻璃陶瓷的玻璃转变温度(Tg)和析晶峰温度分别为580 ℃和740 ℃。采用先制备玻璃再进行热处理的方法(二步法)很容易生成CaTiO3晶相,而采用从熔融温度降低到核化温度成核,再升高到晶化温度进行热处理的方法(一步法),可获得稳定的2M型CaZrTi2O7晶相,且CaZrTi2O7晶粒呈树枝状分布在玻璃基质中。玻璃陶瓷固化体中B和Na元素的归一化质量损失在14 d后达到稳定值(约1 mg/m2),Nd元素的归一化质量损失在28 d后达到稳定值(约0.2 mg/m2),均较硼硅酸盐玻璃固化体的低1个数量级。

     

    Abstract: Nd-doped zirconolite-based glass-ceramics were prepared by melting-heat treatment technique. The effects of heat treatment processing on phase structure of the glass-ceramics were investigated. The leaching properties of the glass-ceramics were also evaluated by static leaching experiments (product consistency test, PCT). The results show that glass transformation temperature (Tg) and crystallization temperature of the glass-ceramics are about 580 ℃ and 740 ℃, respectively. CaTiO3 phase forms easily when the glass-ceramics were prepared by two-step method, i.e. the glass was prepared first, and then it was heat-treated at the crystallization temperatures. 2M-zirconolite phase can be obtained by one-step method, i.e. the heat-treatment immediately followed by the melting process. In addition, the zirconolite crystals exhibit a dendritic shape. The normalized mass loss of B and Na in the glass-ceramics remains almost unchanged (about 1 mg/m2) after 14 days, while the normalized mass loss of Nd reaches stable value (about 0.2 mg/m2) after 28 days. The normalized mass loss of B, Na, and Nd in the glass-ceramics is an order of magnitude lower than that of borosilicate glasses, respectively.

     

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