RECYCLING OF GROG BY ADDITION INTO HEAVY CLAY CERAMIC MANUFACTURING

摘要

In the county of Campos dos Goytacazes, north of the State of Rio de Janeiro, Brazil, there is a large production of heavy clay ceramic for civil construction, mainly perforated bricks. A percentage of these bricks are damaged during the firing stage and after crushing is a powder waste denoted as grog. The amount of damaged ceramics generated after the firing stage is estimated to be at least 850 ton per month. This work investigates the recycling in the proper heavy clay ceramic processing. The characterization of the grog was performed by XRD, XRF, sieving and sedimentation method to determine its particle size distribution, DTA/TG and SEM. Grog originated from bricks produced at 500-600°C, was added up to 20 wt % into the clayey body. Rectangular test specimens were prepared extrusion, dried until constant weight and then fired in an industrial furnace at 970°C. Body samples were initially tested for plasticity. After firing, samples were then tested for linear shrinkage, water absorption and mechanical strength. The results have shown that grog addition improves the workability/plasticity of the investigated clay. With respect to the physical and mechanical properties, it was observed that the grog decreased the linear shrinkage and practically did not change the water absorption and the mechanical strength of the fired ceramic. These results indicate the possibility of recycling fired brick waste into the own ceramic processing.