ZIRCONIA SOL, PREPARATION THEREOF, SLURRY FOR USE IN THE PRODUCTION OF POROUS CERAMIC, AND POROUS CERAMIC PRODUCED FROM SAID SLURRY

摘要

A highly concentrated zirconia sol having a long-term stability is prepared according to the present invention by heating an aqueous solution of a zirconium salt in the presence of urea to give a clear zirconia sol, concentrating said sol through ultrafiltration membrane, and further concentrating the resultant sol by heating at a temperature of 80°C or below. If necessary, a chelating agent and a compound of a metal other than zirconium may be added to this sol. A slurry prepared by adding minute refractory particles to this sol is useful as a raw material of porous ceramic, and a ceramic produced by firing said slurry is suitably used in making a casting mold.