CHARACTERIZATION AND REUSE OF FIRED CERAMIC SCRAPS IN CERAMIC PRODUCTS

Abstract

Energy conservation and environmental safety have become increasingly important concepts in people’s life all around the world. Energy saving in industry as well as utilizing or recycling industrial wastes means more economic production. In countries having regulations for environmental protection that are strictly applied, there is a growing trend towards getting rid of the polluting waste, even if costly. That is why there have been a large number of trials for the incorporation of diverse wastes in the manufacture of ceramic tiles. The present work aims at recycling fired ceramic waste collected from different production lines in manufacturing ceramic tiles. The procedure used in this research involved the following steps: 1- Collection and assessment of raw materials for standard tiles: This step is concerned with choosing the individual raw materials from the storage area by quartering (ball clay, albite, potash feldspar, talc, imported albite, imported ball clay, kaolin, and silica sand). Assessment of raw material was carried out by determining their physical properties, chemical analysis and mineral compositions by the standard techniques. 2- Collection and assessment of fired ceramic wastes: The fired ceramic wastes (scrap) of three types ceramic products (floor, porcelain tiles, and sanitary ware) were collected and characterized by XRF, XRD analysis before adding to the basic tile mixture. Waste scrap from three different production lines was collected. This consisted of 75% floor tile scrap, 15% porcelain tile scrap and 10% sanitary ware scrap. XRD results for scarp revealed that scrap consists of quartz, soda and potash feldspars and mullite. The presence of this latter is expected since some of the original bodies which constitute the scrap were fired well above the temperature of formation of mullite. A standard sieve set equipped with an electric shaker was used to obtain the screen analysis of scrap waste. The mean particles diameter was found to equal 0.44 mm. This value is typical of tile or porcelain bodies. 3- Preparation, pressing, firing, and testing of standard bodies and waste-mixed bodies: Standard bodies for both floor and porcelain tiles with different compositions of waste-mixed bodies were prepared, by wet grinding and dry pressing at a maximum pressure of 300 bar (For ceramic floor tiles) and 400 bar (for porcelain tiles) then fired up to 1180 °C or 1215oC respectively, in a heating cycle of 40 min. or 65 min respectively in a fast firing roller kiln used for normal production. In both cases, the percent waste was varied from 4 % to 15 %. 4- Quality assessment for final product: The properties of produced tiles were compared to local standards to assess the viability of incorporating waste in floor, porcelain tiles.