This work has as objective to use waste from the sawing of ornamental rocks in mixture with clay, for obtaining of electric porcelain, with application as insulator of low tension. Three formulations with 40, 50 and 60 % in weight of waste from the cutting of fine gnaisse mixed with kaolinitic clay were studied. Prismatic bars were prepared by uniaxial molding process and submitted to a sintering temperature at 1200°C, for 15 minutes. The fired bodies were submitted the physical and mechanical tests for the determination of the water absorption, skrinkage and bending strength. The crystalline phases were identified for X ray diffraction and the microstructure of the compositions was evaluated by scanning electron microscopy equipped with microanalysis by energy dispersion (EDS). The best acting of the physical and mechanical characteristics were presented by the sample with 60% in weight of the waste, being compatible with the behavior of ceramic materials. The microstructure of sintered bodies was also similar to presented for the traditional porcelains, composed of mullite, quartz and glassy phase. The results show that the waste of the industrial production of ornamental rocks is possible to substitute quartz and feldspar of the typical mass of porcelain, besides reducing the sintering temperature.
Fine gnaisse; microstructure; electrical porcelain; waste
