Stabilization of thermal storage ceramics via the phase reconstruction of ferrotitanium slag and migration of Mg element

Abstract

AbstractIn this study, aluminum titanate/anorthite (Al2TiO5‐CaAl2Si2O8) ceramics were fabricated from ferrotitanium slag through phase reconstruction. Stabilization of the ceramic was achieved by migration of Mg element into Al2TiO5 phase. The results indicated that optimal performance was achieved with the addition of 4 wt% MgO and 60 wt% ferrotitanium slag at 1370°C. The ceramic exhibited bulk density of 3.11 ± 0.01 g/cm3, thermal storage density of 1.51 kJ/cm3, and thermal expansion coefficient of 3.40 × 10−6/°C (1000°C), respectively. Additionally, the solid solution of Mg2+ in the Al2TiO5 lattice reduced the formation of microcracks and enhanced the mass transfer process. Consequently, the sintering temperature decreased from 1415°C to 1370°C while the bending strength increased from 61.25 ± 1.05 MPa to 75.92 ± 7.72 MPa. Furthermore, finite element simulation demonstrated that higher thermal expansion led to concentrated thermal stress, potentially increasing the possibility of ceramic cracking. This research provides a new strategy for preparing low thermal expansion ceramics from titanium‐containing solid waste.