钕在钙钛锆石和榍石组合矿物中的固溶机制

Mechanism of Solidification Neodymium in Assorted Minerals of Zirconolite and Sphene

以ZrSi O4、CaCO3、Ti O2、Al2O3、Nd2O3为原料,引入Al3+作价态补偿,通过固相反应制备包容模拟三价锕系核素Nd的钙钛锆石(CaZrTi2O7)和榍石(CaTiSi O5)组合矿物固化体。利用X射线衍射(XRD)、扫描电镜/能谱仪(SEM/EDS)研究其矿相组成、微观结构和元素分布,探讨Nd在钙钛锆石和榍石组合矿物固化体中的固溶机制。研究表明:钙钛锆石和榍石组合矿物固化体较佳的合成条件是在1 230℃条件下保温30 min,较佳配方的摩尔比为n(Ca1-x/2-y/4Nd(x+y)/2Zr1-y/4Alx/2Ti2-x/2O7)∶n(Ca1-xNdxAlxTi1-xSi O5)=[4/(4-y)]∶1;Nd3+能够进入钙钛锆石和榍石晶格,榍石能够固溶Zr4+、Al3+、Nd3+,Zr4+和Nd3+取代Ca2+位,Al3+占据Ti4+位,钙钛锆石能够固溶Al3+、Nd3+,Nd3+进入Ca2+位和Zr4+位,Al3+占据Ti4+位。

The assorted minerals of zirconolite and sphene doping simulated actinide neodymiumwere fabricated by solid reaction,using zircon,titanium dioxide,calcium carbonate,Al2O3 as raw materials.The phase assemblage,microstructure and elemental distribution were researched by X-ray diffractometer,scanning electron microscopy with energy dispersive spectrometer.The mechanism of solidification neodymium in assorted minerals of zirconolite and sphene was probed into.The better condition synthesizing the assorted minerals of zirconolite and sphene doping neodymium is holding 30 min at（1 230 ℃）,and the better formula is n（Ca_（1-x/2-y/4）Nd_（（x＋y）/2）Zr_（1-y/4）Al_（x/2）Ti_（2-x/2）O_（7））∶（n（Ca_（1-x）Nd_（x）Al_（x）Ti_（1-x）SiO_（5）））=[4/（4-y）]∶1.Nd^（3＋） can enter crystal lattices of zirconolite and sphene.Sphene can immobilize Zr^（4＋）,Al^（3＋）and Nd^（3＋）;Zr^（4＋） and Nd^（3＋） replace Ca^（2＋）,and Al^（3＋） replaces Ti^（4＋）.Zirconolite can immobilize Al^（3＋） and Nd^（3＋）;Nd^（3＋） replaces Ca^（2＋）and Zr^（4＋）,and Al^（3＋） and replaces Ti^（4＋）.