第39卷第9期 第39卷第9期 2011年9月
许文祥等:集料形状和尺寸对混凝土边界效应的影响
· 1505 ·Vol. 39,No. 9 September,2011
硅 酸 盐 学 报
JOURNAL OF THE CHINESE CERAMIC SOCIETY
钙钛锆石和榍石的组合矿物固溶铀
滕元成,桂成梅,任雪潭 (西南科技大学,四川省非金属复合与功能材料重点实验室–省部共建国家重点实验室培育基地,四川 绵阳 621010)
摘 要:以ZrSiO4、CaCO3、TiO2、Al2O3及UO2(NO3)2.6H2O为原料,通过固相反应制备掺U钙钛锆石(CaZrTi2O7)和榍石(CaTiSiO5)的组合矿物。用X射线衍射、背散射电子图像、能谱仪等分析手段研究组合矿物的制备及其对U固溶的情况。结果表明:制备掺U钙钛锆石和榍石组合矿物的较佳配方摩尔比为n(CaZr1–7xU7xTi2O7):n(Ca1–xUxAl2xTi1–2xSiO5) = 1:(1–7x),较佳煅烧条件为1 230 ℃保温30 min;U4+固溶在CaZrTi2O7的Zr4+位和Ca2+位及CaTiSiO5的Ca2+位,其最大固溶质量为28.64%。
关键词:钙钛锆石;榍石;铀;固溶体
中图分类号:TL941 文献标志码:A 文章编号:0454–5648(2011)09–1505–06 网络出版时间:2011–08–29 14:36:00
DOI:CNKI:11-2310/TQ.20110829.1436.024
网络出版地址:http://www.cnki.net/kcms/detail/11.2310.TQ.20110829.1436.024.html
Solidifying Uranium in Assembled Minerals of Zirconolite and Sphene
TENG Yuancheng,GUI Chengmei,REN Xuetan
(State Key Laboratory Cultivation Base for Nonmetal Composite and Functional Materials, Southwest University of
Science and Technology, Mianyang 621010, Sichuan, China)
Abstract: Assembled minerals of zirconolite and sphene doped uranium were synthesized by solid-reaction, using zircon, calcium carbonate, titanium dioxide, alumina, and uranyl nitrate hexahydrate as raw materials. Preparation of the assembled minerals and so-lidifying status of uranium in the preparation were researched by various methods, including X-ray diffraction, backscattering scan-ning electron microscopy, and energy dispersive spectroscopy. Results indicate that optimum conditions for synthesizing the assem-bled minerals doped uranium include holding for 30 min at 1 230 ℃, and a mole ratio formula of n(CaZr1–7xU7xTi2O7):n(Ca1–xUxAl2x? Ti1–2xSiO5) = 1:(1–7x). Uranium ion is solidified in the Zr4+ lattice and Ca2+ lattice of zirconolite, and the Ca2+ lattice of sphene. The maximum solid solution mass fraction of U4+ in the assembled minerals is 28.64%.
Key words: zirconolite; sphene; uranium; solid solution
钙钛锆石(CaZrTi2O7)是地球上稳定的矿物之一,也是锕系核素的主要寄生矿相,被认为是固化含锕系核素高放废物(high-level radioactive waste,HLW)理想的固化介质材料[1–3]。榍石(CaTiSiO5)具有良好的物理化学稳定性,能与很多放射性裂变产物及锕系核素形成稳定的固溶体,也是固化锕系HLW理想的候选矿物之一[4–5]。Muthuraman等[4]采用共沉淀法、溶胶–凝胶法和液相燃烧法在1 000~1 200 ℃合成了单相CaTiSiO5矿物,该工艺的原料价格高、工艺复杂,不利于工程应用。国内外对钙钛锆石和榍石组合矿物固化处理高放废物的研究较少。滕元
收稿日期:2011–05–03。 修改稿收到日期:2011–05–21。 基金项目:国家基础科研计划(B3120110001)资助项目。 第一作者:滕元成(1964—),男,硕士,教授。
成等[6–8]采用固相反应工艺研究钙钛锆石和榍石组合矿物的制备及其对模拟三价锕系核素钕的固溶情况。
实验中以较廉价ZrSiO4、TiO2、CaCO3、Al2O3及UO2(NO3)2?6H2O为原料,采用固相反应工艺制备掺U4+钙钛锆石和榍石组合矿物固溶体,并研究组合矿物的制备工艺及其固溶U的情况。
1 实 验
1.1 配方设计
UO2(NO3)2.6H2O中的U为6价,U6+的离子半径较小,不易进入稳定矿物相应的晶格。研究[9]表
Received date: 2011–05–03. Approved date: 2011–05–21. First author: TENG Yuancheng (1964–), female, master, professor. E-mail: tyc239@163.com