Development of Glass-Ceramics Containing Possible NASICON-Type Phases Derived from Soda-Lime Glass Waste, Zirconia Residue, and Bentonite

Glass-ceramic foams (BVZ: bottle glass waste–zirconia residue–bentonite) were produced using the polymeric replica method from low-cost raw materials, comprising approximately 85 wt% bottle glass waste and zirconia residue, and 15 wt% regional bentonite. To evaluate the effect of zirconia residue on the microstructure and physicochemical properties of the BVZ foams, aqueous precursor suspensions were prepared with varying proportions of bottle glass waste (59.7–69.7 wt%) and zirconia residue (14.9–19.9 wt%), and sintered at 750 °C, 800 °C, and 850 °C. X-ray diffraction (XRD) analysis revealed a reduction of the amorphous halo (15–35° 2θ) and an increase in crystallinity with increasing temperature, indicating devitrification of the glassy matrix. The main crystalline phases identified were zircon (ZrSiO₄), nepheline (NaAlSiO₄), AlPO₄, and zirconia (ZrO₂), with evidence of minor domains structurally compatible with NASICON-type phases (NaZr₂(PO₄)₃). In general, glass-ceramic foams produced with high waste content showed greater densification and reduced porosity at 850 °C. The mechanical strength was sufficient for handling and assembly in electrochemical cell components, while the reduced brittleness supports safe processing and indicates potential for scalable manufacturing.