Synthesis and characterization of Ba and Sr celsian ceramics from zeolites obtained from amazonian bauxite waste clay

This study explored the use of bauxite washing clay (BWC), a mining residue from the Amazon region, as a raw material for the synthesis of zeolites, followed by their conversion into barium and strontium celsian ceramics. The BWC, rich in gibbsite and kaolinite, demonstrated significant potential due to its high aluminum and silicon content. Zeolites were synthesized through alkaline activation with 1 M NaOH at 350 °C for 4 h, followed by hydrothermal treatment at 100 °C for 24 h. Ion exchange with Ba²⁺ and Sr²⁺ cations was then performed, and the obtained materials were thermally treated at 1200 °C. The results showed the formation of monoclinic barium celsian with high crystallinity, while Sr-celsian exhibited partial conversion, retaining nepheline as a secondary phase. Monoclinic barium celsian exhibited superior mechanical properties, achieving a compressive strength of 15.9 MPa in compositions with lower silica content, whereas Sr-celsian reached 11.94 MPa. In conclusion, this study highlights the potential of BWC as a valuable and sustainable precursor for advanced ceramic production.