Zircon and alumina are two raw materials used for the production of ceramic materials with good thermal-chemical properties. As shaping technology in the ceramic industry it is use, among other technologies, the casting of aqueous suspensions in plaster mouldings, for small series and complicated thin section forms or simple thick section forms.

The aim of our paper is to present the preparation conditions for some aqueous suspensions of non-plastic materials and some of their characteristics.

There were prepared some alumina-zircon concentrated aqueous suspensions in order to study the influence of water and additives amount and the homogenisation-grinding time on the suspension properties, as well. The water amount necessary for obtaining the suspensions depends on the grinding time and on the additives amount. There were used different values of water amount for homogenised suspensions between 3 and 9 hours. The amount of additives varied between 0.30% ÷ 0.38%. The obtained pH values with a pH-meter Consort P901, varied between 7.23 ÷ 9.52. It was not added hydroxide for pH adjustment. The volume weight, average dimension of the particles, the grain-size distribution and viscosity were determined.

After preparation and analysis of casting samples the correlation of the aqueous suspensions optimum parameters with the preparation conditions are emphasized.