NOVEL AND RAPID DRYING CHARACTERIZATION TEST SUITABLE FOR THE BRICK AND TILE INDUSTRY

The industrial raw material compositions in brick or tile production are normally adapting from time to time with novel clays. The proper raw material change must be based on the reliable raw material characterization tests. Regardless to the fact that commonly used (Bigot, Muller-Biehl, Ratzenberger, Piltz, Hermansons, etc.) drying sensitivity criterions allow the comparison of different raw materials they are not related with the mineral composition and mechanical nature of clays. Besides these are time-demanding tests. The X-ray characterization of raw material is reliable only when orientated samples are prepared. In other cases, it is necessary to have additional characterization test such as thermo-differential (DTA) and thermo-gravimetric (TG) analysis in order to confirm the presence or absence of individual clay minerals. The quantity of the interlayer water content present in clays is in direct correlation with the mineralogical composition and the clay type. This effect can be easily qualified on the DTA/TG curves. This was a trigger for establishing the novel rapid drying sensitivity criteria. The analysis of different raw materials has confirmed that the moisture loss registered on TG curves at 2000C can be used as novel drying sensitivity criterion. This value is respectively for insensitive raw materials less than 2.0 while for highly sensitive one is larger than 2.80. The proposed method is very simple, rapid and reliable for the application in brick and tile industry. The second objective of this paper was to compare the results of the proposed method with the widely used Bigoth, Ratzenberg and Piltz tests. A good correlation was found.