Elaboration and Characterization of Local Kaolin-based Materials

Kaolin is one of the most widely used mineral raw materials in ceramic compositions. The study described in this work concerns local kaolins used in the ceramics industry, i.e. kaolins from Djebel Debbagh and Tamazert. The elaboration and characterization of materials prepared from the two types of kaolins DD3P type 22% alumina, DD3R type 36% alumina and derivatives of another local kaolin KT2 were carried out by different analytical methods particularly : DRX, ATG, and SEM; we therefore deduce the mineralogical composition of these products. The thermal behavior of the two kaolins, heated between 1000°C and 11000°C and 1300°C and quenched, shows new phases: mullite from 1000°C and cristobalite nanocrystals from 1150°C. The dilatometric behavior of mixtures prepared from these kaolins in the raw state and sintered at 1200°C shows the various shrinkages significant of the transformations of the constituents of each mixture during heating. Temperature and holding time have an effect on the mechanical properties of the prepared materials.