Possible use of waste olivine powders from a foundry process into the ceramic industry: Sintering behaviour of olivine, kaolin and their blends

The present basic research aims to evaluate the possible recycling of olivine, a by-product of a foundry process, into the ceramic industry. With this goal in mind, olivine powders (O) were milled alone or blended with 20, 40, 60 and 80 wt% of a high grade kaolin (K) by attrition milling to obtain powders of different composition. Samples made with K alone were also prepared as blank composition. All mixtures were dried, sieved, uniaxially pressed into specimens and air sintered for 1 h at temperatures ranging from 1100 to 1400 °C. The resulting materials were characterized by water absorption, shrinkage and phase composition in order to test their sintering behaviour. It was observed that all compositions, sintered below 1100 °C display high open porosity, but enter into the final sintering stages between 1150 and 1200 °C as a function of their compositions, when their water absorption lowers below 5%.