Application of emanation thermal analysis for characterization of intermediate products of urania and thoria ceramics

Emanation thermal analysis (ETA) is demonstrated as a tool for checking the processes taking place in the preparation of urania ceramics from uranyl gel and urania powder. By means of this method solid phases arizing during heat treatment of the uranyl gel microspheres prepared by internal gelation technique were characterized. The differences in thermal behaviour of various uranyl gel samples were shown, the samples differing in the concentration of uranium and gelation additives (carbamide and urotropine), in the way of drying, washing and aging of the gel. The differences in the sinterability of urania powders (delivered commercially) were tested by means of ETA during the heat treatment in reducing atmosphere. For thoria powder, obtained by the decomposition of thorium oxalate, the kinetics of the changes taking place at early sintering stages, was determined by means of emanation thermal analysis. The emanation thermal analysis has been recommended as the method for characterization of intermediate products of urania and thoria ceramics. (orig.)