Pressed ceramic plates were made from mixtures with different proportions containing kaolinite clay, silica extracted from the rice husk ash after controlled burning at controlled temperature and sludge from a water treatment plant. Physical properties such as density, water absorption and porosity, mechanical properties such as compressive strength, and thermal characteristics such as thermal conductivity of the ceramic plates after burning (DIN EN12667) were evaluated. The silica when inserted in the kaolinite clay can have a gradual increase of its performance, be reduced in the porous phase, with reduction of the thermal conductivity and increase of the mechanical resistance. The use of the sludge from a water treatment plant when incorporated to the ceramic mass is a great number of peaks of charge and of crystallization, expressive increase of porosity and decrease of the thermal and mechanical resistances. As ceramic plates with a trace 72% kaolinite clay, 18% rice husk and 10% sludge from a water treatment plant show lower thermal conductivity 0.2574 W m-1K-1, and a higher compressive strength of 172.12 MPa when compared to the other plates tested where the substitutions for sludge from a water treatment plant occurred.
Keywords:
rice husk ash; sludge from a water treatment plant; ceramic plates
