Development of porous ceramics for air diffuser applications

Abstract

Porous ceramic for bubbling air into water at 1 bar of pressure was successfully developed. Different compositions were tested. The use of superground alumina was not successful because the particle size was too small and the pores were closed thereby forbidding any air transport through the ceramic. Additions of corn starch to this material did not help much because any contribution of porosity was closed porosity and that was useless in air transport. Limited success was accomplished when clay, quartz and corn starch were used but this time the pressure needed to produce a reasonable amount of bubble in water was higher than 1 bar which was the initially set goal for this project. Bayer alumina was used as a replacement for superground Alcoa alumina to help with porosity because these powders are well known to be agglomerated and to offer high amount of porosity Smaller fraction of quartz was added to help with strength and clay to assist in forming and very good results were obtained. Ceramics made from 50% Bayer alumina and 50% clay provided very good oxygenation of water. However, their strength was not as good as samples made from 50% Bayer alumina, 20% quartz and 30% clay. These latter samples had higher strength and slightly lower oxygenation. The use of these ceramics as air diffusers can help oxygenate water which is needed in a lot of different applications.Key words: Porous ceramic, air diffuser, alumina.