Influence of the mixing speed and time on the mechanical and physical properties of laminated ceramic plates

摘要

The mechanical and physical properties of tiles are strongly dependent on the solid structure that is generated during processing, especially before the firing stage. Mixing process can be used to improve the chemical and physical uniformity of the ceramic mixture, reducing the segregation and the heterogeneity of the components. The mixing speed improves the movement of the particles and the mixing rate. In this work appropriate ceramic mass for the production of ceramic plates for tiles was used. The moisture and the amount of binder were appropriately selected so that the mass presented the consistence demanded by the lamination process. The mixing speed varied from 30 to 90 rpm, for 30 and 60 minutes. The plates produced by the lamination process were sintered at 1050°C, 1100°C, 1150°C and 1170°C/30min. The physical characteristics of the plates, such as water absorption, apparent porosity and apparent density, were determined through the method described in ISO 10545/NBR 13818 and the Archimedes principle. The linear shrinkage was evaluated from the dimensional variation measurement as a function of the temperature. The best properties were observed for the specimens obtained with mixture submitted to the largest mixing speed and time. The specimens presented strength values that vary from 17.00 N/mm{sup}2 to 38.00 N/mm{sup}2, linear shrinkage from 0.3 to 6.5% and water absorption from 0.4 to 17.00%.