Cleaner production of porcelain tile powders. Granule and green compact characterization

A new ceramic powder preparation process, the droplet–powder granulation process (DPGP), was recently proposed in pursuit of energy/water conservation and environment protection for sustainable development of the ceramic industry. This study characterizes the DPGP granules and resulting pressed green compacts and compares them with those obtained using traditional spray-drying (hereafter SD) and granulation (hereafter G) processes. Powder and granule properties (granule size distribution, flowability, microstructure, yield pressure, etc.), powder pressing behaviour, and green compact properties (microstructure, bending strength, etc.) were determined. The properties of the DPGP powder and the resulting compacts displayed an intermediate performance between those of the powders and compacts obtained by the SD and G processes, demonstrating the feasibility of the DPGP process in the pre-firing stage of porcelain tile manufacture. The study also shows that, in addition to the key spray-mixing step, the subsequent rolling treatment also plays a major role in DPGP granule formation.