Trace detection of impurity phase in preparation of ye'elimite by Eu3+ fluorescence prober

In this study, based on the phase transition of Ca4Al6SO16 from the low-temperature orthorhombic phase (o-Ca4Al6SO16) to high-temperature cubic phase (c-Ca4Al6SO16), the existent impurity phase in o-Ca4Al6SO16 with excess addition of CaSO4 is verified as Ca3Al2O6 rather than Ca12Al14O33 with the closest Ca/Al ratio to the main phase. Meanwhile, the Eu3+ fluorescence prober shows a more sensitive detection capability than x-ray powder diffraction, especially when the content of Ca3Al2O6 below 2 wt. %. By virtue of the different crystal-field splittings of Eu3+ ions in o-Ca4Al6SO16 and Ca3Al2O6, the near-pure o-Ca4Al6SO16 phase with not more than 0.03 wt. % of Ca3Al2O6 is also obtained. In addition, combining the spectral analysis and structural refinement, the relationship between the content of Ca3Al2O6 and spectral change of Eu3+ ions are determined, and the obtained results show good linear change rules. As a result, what discussed in this research not only facilitates the verification and content determination of impurity phases in the preparation of Ca4Al6SO16, but also provides a promising strategy of phase identification through a combination of the phase-change structural analysis and lanthanide-doped fluorescence prober.

Source: Sensors and Actuators B: Chemical - May 25, 2019 Category: Chemistry Source Type: research