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硅酸盐通报 ›› 2022, Vol. 41 ›› Issue (11): 3861-3869.

所属专题: 玻璃

• 微晶玻璃 • 上一篇    下一篇

CaO含量对镧硼硅酸盐玻璃陶瓷晶相和化学稳定性的影响

傅茂洋, 廖其龙, 王辅, 胥有利, 何泽旭, 竹含真   

  1. 西南科技大学材料与化学学院,绵阳 621010
  • 收稿日期:2022-07-29 修订日期:2022-09-11 出版日期:2022-11-15 发布日期:2022-12-12
  • 通信作者: 廖其龙,博士,教授。E-mail:liaoqilong@swust.edu.cn
  • 作者简介:傅茂洋(1998—),男,硕士研究生。主要从事硼硅酸盐玻璃及玻璃陶瓷固化的研究。E-mail:3317804017@qq.com
  • 基金资助:
    国家自然科学基金(51702268);环境友好能源材料国家重点实验室自主课题(21fksy12)

Effect of CaO Content on Crystalline Phases and Chemical Stability of Lanthanum Borosilicate Glass-Ceramics

FU Maoyang, LIAO Qilong, WANG Fu, XU Youli, HE Zexu, ZHU Hanzhen   

  1. School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, China
  • Received:2022-07-29 Revised:2022-09-11 Online:2022-11-15 Published:2022-12-12

摘要: 采用熔融冷却法制备了Na2O-CaO-La2O3-B2O3-SiO2玻璃,经热处理获得了硅酸盐氧基磷灰石硼硅酸盐玻璃陶瓷,并采用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、差示扫描量热法(DSC)、产品一致性试验(PCT)法等方法探究了CaO取代SiO2对该硼硅酸盐玻璃陶瓷物相、微观结构和化学稳定性的影响规律。结果显示:随着CaO含量增加,硅酸盐氧基磷灰石晶相衍射峰增强,其他晶相的衍射峰减弱直至消失,当CaO摩尔分数为15%时获得只含CaLa4(SiO4)3O晶相的玻璃陶瓷样品;CaO含量会对玻璃陶瓷的晶相种类和晶体形状、大小、分布产生影响,CaO含量变化会造成陶瓷相晶体发生团簇和长大;采用PCT法浸泡28 d后,所有样品关于Si、Ca、La三种元素的归一化浸出率(g·m-2·d-1)均保持在10-3数量级以下,表明其具有优异的化学稳定性,且CaO摩尔分数为15%的玻璃陶瓷样品化学稳定性最优异。研究结果表明,硅酸盐氧基磷灰石硼硅酸盐玻璃陶瓷是固化富La和某些锕系元素高放废物的潜在基材。

关键词: CaO, 硼硅酸盐玻璃陶瓷, 硅酸盐氧基磷灰石, 晶相, 浸出率, 化学稳定性

Abstract: The Na2O-CaO-La2O3-B2O3-SiO2 glass were prepared by melt-quenching method. Then, the silicate oxyapatite borosilicate glass-ceramics were obtained by heat treatment of the prepared glass. After that, the X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and the product consistency test (PCT) were used to explore the effect of CaO substitution for SiO2 on phases, microstructure and chemical stability of borosilicate glass-ceramics. The results show that with the increase of CaO content, the diffraction peaks of silicate oxyapatite crystalline phase are enhanced, and the others are weakened until disappearing. When the mole fraction of CaO is 15%, only the CaLa4(SiO4)3O crystalline phase is detected in the glass-ceramics samples. The crystalline phases types, shapes, sizes and distributions of glass-ceramics are affected by CaO content, and the cluster and growth of ceramics crystalline phases are caused by the change of CaO content. After immersing by the method of PCT for 28 d, the normalized leaching rates (g·m-2·d-1) of Si, Ca and La of all samples remain below the order of 10-3, indicating that the glass-ceramics samples have excellent chemical stability. In addition, the glass-ceramics samples containing the CaO mole fraction of 15% exhibit the best chemical stability. The results show that the borosilicate glass-ceramics containing silicate oxyapatite are potential substrates for immobilization high-level radioactive wastes containing La-rich and some actinide rich.

Key words: CaO, borosilicate glass-ceramics, silicate oxyapatite, crystalline phase, leaching rate, chemistry stability

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