固相反应合成钙钛锆石和榍石

Synthesis of Zirconolite and Sphene by Solid-state Reaction

钙钛锆石(CaZrTi2O7)和榍石(CaTiS iO5)是人造岩石固化放射性废物理想的介质材料。以天然锆英石(ZrS iO4)、模拟放射性焚烧灰、CaCO3、TiO2为原料,借助失重—差热(TG-DTA)分析和X射线衍射(XRD)分析,研究了合成CaZrTi2O7和CaTiS iO5的固相反应。结果表明,随着模拟放射性焚烧灰掺量的增加,合成CaZrTi2O7和CaTiS iO5的温度降低,ZrS iO4的分解温度降低。模拟放射性焚烧灰掺量(质量分数)分别为20%、40%、60%,合成CaZrTi2O7的最低温度分别是1050℃、950℃、900℃,合成CaZrTi2O7的最低温度分别是950℃、950℃、900℃,合成CaZrTi2O7和CaTiS iO5的最佳合成温度分别为1260℃、1230℃、1200℃。

Zirconolite(CaZrTi_2O_7) and sphene(CaTiSiO_5) are considered as perfect host materials for Synroc immobilization of radioactive waste.The solid-state reactions synthesized CaZrTi_2O_7 and CaTiSiO_5 were studied,using natural zirconite(ZrSiO_4),simulated radioactive incineration ash(SRIA),CaCO_3 and TiO_2 as raw materials,by means of thermogravimetry-differential thermal analysis(TG-DTA),X-ray diffraction analysis(XRD).The results indicate that the synthesis temperatures of CaZrTi_2O_7 and CaTiSiO_5,and the decomposing temperature of ZrSiO_4 dropped along with the increasing of SRIA.When the content of SRIA is 20wt.%,40wt.% and 60 wt.%,the lowest synthesizing temperatures for CaZrTi_2O_7 are 1050 ℃,950 ℃ and 900 ℃ respectively; for CaTiSiO_5 950 ℃,950 ℃ and 900 ℃ respectively;and the optimum synthesizing temperatures for CaTiSiO_5 and CaTiSiO_5 are 1260 ℃,1230 ℃and 1200 ℃ respectively.