Kinetics in Solid-state Synthesis of Calcium-barium Sulfo-ferritealuminate (C₃BA_3−yF_y$) Mineral and Its Formation Mechanism

Abstract

Calcium-barium sulfo-ferritealuminate (C₃BA_3−yF_y$) was synthesized by doping Ba-bearing calcium sulphoaluminate(C₃BA₃$) with Fe³⁺. The effects of calcination temperature, holding time and Fe-doping concentration on the solid-state reaction process of the C₃BA_3−yF_y$ (y=0, 0.2, 0.25, 0.4, and 0.6) were investigated by the Rietveld/XRD quantitative phase analysis. The experimental results show that Fe-doping not only significantly improvs the synthesis of C₃BA_3−yF_y$, but also reduces the solid-state reaction potential energy barrier and then promots mineral formation. Nevertheless, the mineral begins to decompose when the Fe/Al ratio exceeds 2/13 and the calcination temperature exceeds 1 300 °C. The Ginstling equation is found to be the most appropriate kinetic model for the statistical fitting of C₃BA_3−yF_y$ formation process, based on the mathematical model. It is observed that the apparent activation energy of C₃BA_3−yF_y$ decreases and then increases with increasing Fe-doping concentration.

RIGHTS & PERMISSIONS

Wuhan University of Technology and Springer-Verlag GmbH Germany, Part of Springer Nature