發(fā)布時(shí)間：2018-03-08 20:47

  本文選題：玻璃陶瓷　切入點(diǎn)：氧化鋯　出處：《西南科技大學(xué)》2017年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：高放廢物主要來(lái)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(jìn)入了高放廢物中,因此對(duì)高放廢物的處理是各國(guó)都非常關(guān)注的問(wèn)題。本文以鐵鈉磷酸鹽玻璃(20Fe_2O_3 60P_2O_5 20Na_2O)為基礎(chǔ)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(guò)XRD、FTIR、DSC等測(cè)試手段研究ZrO_2、CeO_2對(duì)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(xué)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(duì)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(duì)ZrO_2 Fe_2O_3 P_2O_5 Na_2O玻璃體系進(jìn)行熱處理時(shí),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(qiáng)后減弱,在650~750℃對(duì)CeO_2 Fe_2O_3 P_2O_5 Na_2O玻璃體系進(jìn)行熱處理時(shí),析出主晶相NaFeP2O7。這兩個(gè)玻璃體系的結(jié)構(gòu)單元以Q1基團(tuán)為主。(2)以ZrO_2、CeO_2作為模擬核廢料氧化物與基礎(chǔ)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(dāng)核廢物的包容量大于55wt%時(shí),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(tuán),包容量增加使Q1基團(tuán)減少,橋氧鍵增加,固化體的化學(xué)穩(wěn)定性得到改善。通過(guò)MCC-1靜態(tài)浸出實(shí)驗(yàn)分析鐵鈉磷酸鹽玻璃陶瓷固化體的化學(xué)穩(wěn)定性發(fā)現(xiàn),在浸泡時(shí)間低于14天時(shí),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(jí)為10-8g/cm2·min。通過(guò)ICP-MS以及ICP-OES測(cè)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(qiáng)的化學(xué)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(hào)：1585489