Improving plasticity of kaolins by high-energy milling for use in porcelain tile compositions
Jorge Luiz Bombazaro, Adriano Michael Bernardin
Abstract
The production of porcelain tiles is increasing in Brazil besides the production of grés tiles and monoporosa is decreasing since COVID 19. Plastic clays are used in the composition of porcelain tiles to give plasticity to the pastes in the forming step. However, there is a shortage of plastic clays in south Brazil, the largest producer of porcelain tiles. Therefore, the aim of this work was to improve the plasticity of two commercially available kaolins by high-energy milling (HEM). Both kaolins were characterized before and after milling by X-ray diffraction, particle size, plasticity, and cation exchange capacity techniques. After high-energy milling, the processed kaolins were used in the composition of a commercial porcelain tile paste. The performance of the paste before and after use of the processed kaolins was determined regarding its firing shrinkage and sintering temperature. The porcelain tile compositions with the high-energy milled kaolins showed less densification during pressing and greater shrinkage after firing, but the tiles presented dimendional stability, improving the quality of the tiles.