MgO-Al2O3-SiO2-ZrO2 system ceramic glass as sintering aids to fabricate Al2O3 ceramic membrane with high acid corrosion resistance

The shortcoming of ceramic membranes is the high cost caused by high sintering temperatures. Sintering aids can be chosen to reduce the sintering temperature. However, it results in the low corrosion resistance, especially in corrosive wastewater treatment and membranes' chemical cleaning processes. Glass phase generated in the sintering is the main factor. In the present work, MgO-Al2O3-SiO2-ZrO2 system ceramic glass is chosen as sintering aids with a crystallinity of 89.63 %. The bending strength of the alumina membrane can be increased from 46.79 MPa of pure alumina to 111.02 MPa with 4.8 wt% ceramic glass addition. The sintering temperature of pure Al2O3 membrane is much higher than 1600 degrees C when the equal bending strength is obtained. The bending strength loss rate of the tubular ceramic membrane is only 5.13 % and 3.85 % after the static stage and dynamic separation for 36 h acid corrosion. MgAl2O4, Mg2SiO4, and ZrO2 crystals locate on alumina particles' necks and provide the membrane with excellent mechanical properties and outstanding corrosion resistance. The Al2O3 membrane has a porosity of 34.06 % and a mean pore size of 1.42 & mu;m, besides, acid corrosion can promote the permeability of membranes.