Fabrication of crystal boundary enhanced magnesia from salt-lake brine avoiding pyrolytic CO2 emission

Conventional electric melting or sintering processes of magnesia from magnesite are usually accompanied by massive energy consumption and CO 2 emissions. This work proposed a novel approach to utilize light-burned magnesium oxide from salt-lake brine to fabricate Y 2 O 3 -doped magnesia without pyrolytic CO 2 emission at a lower sintering temperature. Microstructural evolution, physical properties, pore structure, corrosion resistance and thermochemical stability of the sintered magnesia were evaluated. A favourable crystal boundary with MgO-Y 2 O 3 core-shell structure formed in the sample with 3-5 wt% Y 2 O 3 , and it led improved the thermal stability and vacuum volatilization of the fabricated MgO-Y 2 O 3 . Furthermore, a dense layer of MgAl 2 O 4 spinel on the slag/refractory interfaces of the sample with Y 2 O 3 -adding which contributed to the enhancement in corrosion resistance. An intercrystalline corrosion process and indirect dissolution process explained the degradation processes of the fabricated magnesia with or without Y 2 O 3 -adding, respectively. In summary, our novel design of Y 2 O 3 crystal-boundary enhanced magnesia with a low carbon footprint can achieve high value-added utilization of magnesium resource solid waste from salt-lake brine.