Abstract: In order to study the corrosion mechanism and behavior of high level radioactivity waste borosilicate liquid glass on chrome corundum refractories,the corrosion mechanism of simulated high level radioactivity borosilicate liquid glass on fused cast and sintered chrome corundum refractories at 1 200 ℃ was analyzed and compared by dynamic cylindrical corrosion test combined with thermodynamic calculation.The microstructures and the chemical composition of the two refractories before and after corrosion testing were analyzed with the electron probe X-ray microanalyzer coupled with wavelength dispersive spectroscopy (EPMA-WDS).The corrosion mechanism was discussed.The results show that:(1)(Cr,Al)₂O₃,Al₂O₃,ZrO₂ and SiO₂-rich phases in the both refractories can dissolve into the liquid glass,Al₂O₃ in the (Cr,Al)₂O₃ solid solution dissolves into the glass whereas Cr₂O₃ does not dissolve;(2)liquid glass infiltrates into the fused chrome corundum mainly via the SiO₂-rich phases,but into the sintered chrome corundum through the open pore network,so the corrosion to the fused cast chrome corundum refractories is uniform,while that to the sintered one is uneven;(3)the corrosion resistance of fused cast chrome corundum refractories can be improved by lowering the content of SiO₂-rich phases,that of the sintered one by increasing the (Cr,Al)₂O₃ solid solution content.

Key words: high level radioactivity waste, glass vitrification, borosilicate glass, chrome-corundum, corrosion, microstructure

摘要： 为了研究高放射性废物硼硅酸盐玻璃液对铬刚玉材料的侵蚀机制与行为,采用动态圆柱体侵蚀试验结合热力学计算,对比分析了模拟的高放射性废物硼硅酸盐玻璃液于1 200 ℃侵蚀熔铸铬刚玉及烧结铬刚玉耐火材料的侵蚀机制。采用电子探针结合波谱仪分析侵蚀试验前后的两种铬刚玉耐火材料显微结构和化学组成,并探讨了其侵蚀机制。结果表明:1)两种铬刚玉材料中的(Cr,Al)₂O₃、Al₂O₃相、ZrO₂和富SiO₂相均会溶解入玻璃液中,(Cr,Al)₂O₃固溶体中Al₂O₃溶解入玻璃液中,而Cr₂O₃不溶解;2)玻璃液渗透入熔铸铬刚玉材料中主要通过富SiO₂相,而渗透入烧结铬刚玉材料中主要通过孔隙通道,因此熔铸铬刚玉材料侵蚀较为均匀,而烧结铬刚玉材料侵蚀不均匀;3)降低熔铸铬刚玉材料中的富SiO₂相或增加烧结铬刚玉材料中(Al,Cr)₂O₃固溶体含量,将有利于熔铸或烧结铬刚玉材料抗玻璃液侵蚀性能。

关键词: 高放射性废物, 玻璃固化, 硼硅酸盐玻璃, 铬刚玉, 侵蚀, 显微结构