Porcelain tiles have become one of the most important products of the ceramic industry in the last decade mainly owing to their attractive physical and mechanical properties including high strength, high fracture toughness and density, excellent chemical resistance and low water absorption. The attractiveness of using porcelain has initiated intensive research work for alternative raw materials because of the depletion and the high cost of the usual materials currently used in the ceramic industry. In this research, the aim was to use boron-bearing solid wastes (Ca2B6O11.5H2O) as an alternative fluxing agent to Na-feldspar (NaAlSi3O8) in fast-fired porcelain tile bodies produced under industrial conditions without altering the microstructural, physical and chemical properties required from the final product. For this purpose, the suitability of the colemanite-added porcelain tile bodies to fast-firing conditions was determined using an optical dilatometer. It was then understood that a calcination process was needed in order to effectively use the waste in porcelain tile production. Therefore, the calcination process was applied to the colemanite solid waste before the waste-added bodies were sintered at 1210 oC and 1130 oC. The results were compared with those of the standard porcelain tile bodies produced at the same sintering temperatures. After detailed phase analysis (XRD), microstructural examination (SEM-EDX) and physical-mechanical tests, it was found that the standard porcelain tile body produced at 1210 oC (R1) could be obtained at 1130 oC by adding 5% colemanite solid waste (by weight) to the standard tile body to replace Na-feldspar (R7). This result enables production of porcelain tiles at lower temperatures without changing the other operational parameters, only using colemanite waste as a new fluxing agent in the body formulations.

Keywords: Colemanite, Colemanite waste, Porcelain tile, Sintering agent. Introduction Porcelain tiles