Processing of red ceramic using ornamental rock powder waste

The industry of ornamental rocks from South-Eastern Brazil (Santo Antônio de Pádua, RJ) produces huge amounts of waste in the form of powder. The re-use of ornamental rock powder waste to produce red ceramics for civil construction using the powder technology is described. The waste was added gradually up to 20 wt.%. Rectangular samples were dry pressed and sintered at temperatures ranging from 850 to 1150 °C. The physical–mechanical properties as function of sintering temperature and waste addition are presented. The experimental results revealed that the ornamental rock powder waste is a non-plastic polimineralic material rich in quartz, feldspars, calcite and micaceous mineral. The sintered specimens containing gneiss rock powder waste are adequate for red ceramics, resulting in great advantages in waste minimization.