基于低品位凹凸棒石黏土的陶瓷膜支撑体制备

Porous ceramic membrane support is the basis of ceramic membrane preparation and application, which is the key factor of supporting membrane layer. It provides certain mechanical strength and corrosion resistance for ceramic membrane. Preparation of the ceramic membrane with inexpensive raw materials, such as diatomite, kaolin and fly ash instead of alumina and lower sintering temperature would be beneficial to reduce the cost of the ceramic membranes and consolidate their applications in industrial processes. This work aimed to develop low-cost ceramic membrane supports from low-grade attapulgite clay (ATP). The effects of raw material ratio, pressing pressure, sintering temperature, pore forming agent and sintering additives on the microstructure and performance of the support were systematically studied. The results showed that the addition of appropriate amount of alumina in attapulgite clay can effectively prevent the excessive shrinkage of the support during sintering, and reduce its shrinkage rate from (30±0.12)% to (3.1±0.05)%, which greatly increased the mechanical strength and porosity of the support. The porosity of the support increased with the increase of the amount of pore-forming agent, while the mechanical strength decreased. The mechanical strength increased with the increase of pressing pressure and the porosity decreased. The mechanical strength increased with the increase of sintering temperature. When the sintering temperature exceeded 750℃, the attapulgite structure began to collapse, support began to form densification, and the porosity decreased significantly. When the content of attapulgite clay was 63%, alumina was 29%, pore-forming agent was 6%, the pressing pressure was 10 MPa, and the sintering temperature was 700℃, the perfor-mance of the support was optimal, the average mechanical strength was (18.11±1.83) MPa, and the porosity was (45.94±0.49)%.