Effect of Y2O3 doping on a gehlenite/magnesia-alumina spinel obtained by sintering secondary aluminium ash

Due to the rapid development of China’s regeneration industry, secondary aluminium ash (SAA) has been extensively produced. The reuse of SAA and Y₂O₃ doping was studied in this research. This proved that SAA can turn into a raw material for gehlenite/magnesia-alumina spinels. Furthermore, doping with Y₂O₃ can aggrandize the densification feature of gehlenite/magnesia-alumina spinels. The densification of the gehlenite/magnesia-alumina spinel without Y₂O₃ was lower than that of the doped spinel in the temperature range of 1573 to 1773 K. At 1673 K, 3 wt% Y₂O₃ was added to the gehlenite/magnesia-alumina spinel. It had a density of 2.05 g·cm⁻³ and a compressive strength of 91.2 MPa. Generally, 3 wt% Y₂O₃ was added, and the sintering temperature at 1673 K was appropriate. The elevation of the densification feature was also attributable to the solubility of Y₂O₃ and the formation of a low-viscosity liquid phase such as YCaAl₃O₇. The SAA can be reused for the recovery of gehlenite/magnesia-alumina spinels. Doping it with Y₂O₃ can broaden its reutilization in new water-resistant ceramic materials.