本文選題：玻璃陶瓷　切入點：氧化鋯　出處：《西南科技大學》2017年碩士論文　論文類型：學位論文

【摘要】：高放廢物主要來源于乏燃料的后處理工藝,乏燃料中99%以上裂變產(chǎn)物都進入了高放廢物中,因此對高放廢物的處理是各國都非常關注的問題。本文以鐵鈉磷酸鹽玻璃(20Fe_2O_3 60P_2O_5 20Na_2O)為基礎玻璃,ZrO_2、CeO_2作為模擬核廢物的氧化物,采用傳統(tǒng)的熔融冷卻法制備玻璃固化體,固相燒結(jié)法制備玻璃陶瓷固化體。通過XRD、FTIR、DSC等測試手段研究ZrO_2、CeO_2對鐵鈉磷酸鹽玻璃以及玻璃陶瓷固化體的結(jié)構(gòu)、熱性能以及化學穩(wěn)定性的影響,其中獲得以下主要結(jié)論:(1)鐵鈉磷酸鹽玻璃對ZrO_2、CeO_2的包容量分別為4mol%、24mol%。摻雜4mol%ZrO_2的鐵鈉磷酸鹽玻璃熱穩(wěn)定性最穩(wěn)定,在900℃對ZrO_2 Fe_2O_3 P_2O_5 Na_2O玻璃體系進行熱處理時,析出主晶相ZrP2O7。CeO_2含量的增加使鐵鈉磷酸鹽玻璃的熱穩(wěn)定性先增強后減弱,在650~750℃對CeO_2 Fe_2O_3 P_2O_5 Na_2O玻璃體系進行熱處理時,析出主晶相NaFeP2O7。這兩個玻璃體系的結(jié)構(gòu)單元以Q1基團為主。(2)以ZrO_2、CeO_2作為模擬核廢料氧化物與基礎玻璃混合制備的玻璃陶瓷固化體的主晶相和次晶相分別為NaCe2(PO4)3、NaZr2(PO4)3,大多數(shù)的Zr、Ce元素被包容在晶體相中。當核廢物的包容量大于55wt%時,固化體的析晶效果減弱。固化體的主要結(jié)構(gòu)單元為Q1基團,包容量增加使Q1基團減少,橋氧鍵增加,固化體的化學穩(wěn)定性得到改善。通過MCC-1靜態(tài)浸出實驗分析鐵鈉磷酸鹽玻璃陶瓷固化體的化學穩(wěn)定性發(fā)現(xiàn),在浸泡時間低于14天時,質(zhì)量損失率變化較大,14天之后逐漸趨于穩(wěn)定。失重率的數(shù)量級為10-8g/cm2·min。通過ICP-MS以及ICP-OES測試發(fā)現(xiàn)Zr、Ce離子的元素濃度均在檢出限以下,因此包容ZrO_2與CeO_2的鐵鈉磷酸鹽玻璃陶瓷固化體有較強的化學穩(wěn)定性。
[Abstract]:High level radioactive waste mainly comes from the reprocessing process of spent fuel, and more than 99% fission products in spent fuel are entered into high level radioactive waste. Therefore, the treatment of high-level radioactive wastes is of great concern to all countries. In this paper, glass solidification is prepared by traditional melt cooling method, based on 20FeS / 2Fe2O3 / 60P2O5 / 20Na2O2 as the oxide of simulated nuclear waste. Glass ceramic solidified bodies were prepared by solid-state sintering. The effects of ZrO _ 2C _ 2O _ 2 on the structure, thermal properties and chemical stability of iron sodium phosphate glasses and glass ceramics were studied by means of XRD and FTIR DSC. The main conclusions are as follows: (1) the encapsulation capacity of iron sodium phosphate glass for ZrO _ 2CeO _ 2 is 4mol / 24mol respectively. The thermal stability of the iron sodium phosphate glass doped with 4mol / ZrO _ 2 is the most stable, when the ZrO_2 Fe_2O_3 / P _ 2O _ 2O _ 5 Na_2O glass system is heat-treated at 900 鈩，

本文編號：1585489