Microwave technology applied to the recycling of fine stoneware tiles polishing sludge compared to conventional firing

Microwave technology was a useful heating process when applied to the recycling of fine stoneware tiles polishing sludge. The manufact processed were characterized by low porosity, much lower than that registered for the same formulation heated with conventional firing.The different microstructure has been explained by considering the selective heating phenomenon generated by microwave irradiation: the SiC particles could heat much faster that the aluminosilicate matrix so that to melt the surroundings with a sort of encapsulation process.Conventional heating lead to SiC reaction with oxygen promoting its conversion in CO2 thus creating large pores.