Abstract:
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 (335.8-2 243.0 μg/g) and Sr element (126.3-5 188.2 μg/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
4G5/2→
6H7/2 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
4G5/2→
6H9/2 transition (630-660 nm) to
4G5/2→
6H7/2 transition (580-620 nm).