四川雪宝顶白钨矿的矿物学及发光特征

Mineralogy and Luminescence Characteristics of Scheelite from Xuebaoding,Sichuan Province,China

本文通过对四川雪宝顶地区(瀑口梁、三道气、水晶镇、五铢堂)的白钨矿进行常规矿物学测试、LA-ICP-MS及光致发光光谱(PL光谱)测试,旨在获得其化学成分、矿物学与发光特征。通过高温固相法合成掺杂不同比例Sm、Eu、Dy元素的CaWO_(4)多晶,分析其光致发光光谱以探究Sm、Eu、Dy元素对其红色荧光的影响。结果显示,在中波紫外光(310 nm)照射下,四川雪宝顶地区白钨矿的荧光颜色有分区性,为红色和淡黄色;化学成分测试结果显示,样品含有Sr、Nb、Mn、Mo、稀土元素(REE)等微量元素,整体含有较高的REE总量(335.8-2243.0μg/g)和Sr元素(126.3~5188.2μg/g),在淡黄色荧光区域富集的Nb、Mn、Mo元素,说明白钨矿中Mn、Mo、Nb可提高作为激活剂的三价稀土离子(RE^(3+))的荧光发射强度。PL光谱测试表明,其红色荧光主要是Sm^(3+)、Eu^(3+)的贡献,其次还有Dy^(3+)、Tb^(3+)、Pr^(3+)的影响,淡黄色荧光主要是由Dy^(3+)导致,其次还有Sm^(3+)、Eu^(3+)的影响。本文通过分析合成白钨矿PL光谱得出,Dy^(3+)是Sm^(3+)、Eu^(3+)的敏化剂,Dy^(3+)对Sm^(3+)的荧光发射强度增强的更明显,尤其是Sm^(3+)的^(4)G_(5/2)→^(6)H_(7/2)跃迁(580~620 nm),在天然白钨矿中表现为Dy^(3+)阻碍了Sm^(3+)→Eu^(3+)的能量传递以及部分样品中Sm^(3+)最强发射峰从^(4)G_(5/2)→^(6)H_(9/2)跃迁(630~660 nm)变为^(4)G_(5/2)→^(6)H_(7/2)跃迁(580~620 nm)。

In this study,the conventional mineralogical tests,LA-ICP-MS and photoluminescence spectroscopy(PL spectroscopy)tests were carried out on the scheelite in the Xuebaoding area(Pukouliang,Sandaoqi,Shuijingzhen,Wuzhutang)of Sichuan Province,China,aiming to obtain its chemical compositions,and mineralogy and luminescence characteristics.The CaWO_(4)polycrystals doped with different proportions of Sm,Eu and Dy elements were synthesized by high temperature solid phase method,and their photoluminescence spectra were analyzed to explore the effects of Sm,Eu and Dy elements on their red fluorescence.The results showed that under the irradiation of medium-wave ultraviolet light(310 nm),the fluorescence colour of the scheelite samples from Xuebaoding area of Sichuan is divided into red and light-yellow.The chemical composition test results showed that the samples contain trace elements such as Sr,Nb,Mn,Mo,and rare earth elements(REE).The overall content of REE(335.8-2243.0μg/g)and Sr element(126.3-5188.2μg/g)is high.The Nb,Mn,and Mo elements enriched in the yellowish fluorescence region indicate that Mn,Mo,and Nb in the scheelite can increase the fluorescence emission intensity of the trivalent rare earth ion(RE^(3+))as an activator.The PL spectra showed that the red fluorescence is mainly contributed by Sm^(3+)and Eu^(3+),following by Dy^(3+),Tb^(3+)and Pr^(3+).The light-yellow fluorescence is mainly caused by Dy^(3+),following by Sm^(3+)and Eu^(3+).By analyzing the PL spectra of synthetic scheelite,it was concluded that Dy^(3+)is a sensitizer for Sm^(3+)and Eu^(3+),and Dy^(3+)enhances the fluorescence emission intensity of Sm^(3+)more obviously,especially the^(4)G_(5/2)→^(6)H_(7/2)transition(580-620 nm)of Sm^(3+).In the natural scheelite,Dy^(3+)hinders the energy transfer of Sm^(3+)→Eu^(3+)and the strongest emission peak of Sm^(3+)in some samples changes from^(4)G_(5/2)→^(6)H_(9/2)transition(630-660 nm)to^(4)G_(5/2)→^(6)H_(7/2)transition(580-620 nm).