The effect of the heating temperature on the properties of sintered ceramic bodies from three different contaminated marine sediments was investigated. The sintering behaviour was evaluated by means of the variation of shrinkage degree, bulk density, water absorption, open and closed porosity, while the phases transformation were investigated by differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results have shown that the sintering process follows a viscous liquid phase mechanism due to the formation of a glassy phase. The optimum sintering temperature is 1125ºC for Astilleros and Cuchia sediments and 1150ºC for Raos sample. Above this temperature, a significant overfiring with an increase of closed porosity was observed. Water absorption values and mechanical properties as bending and compressive strengths of sintered bodies show that the investigated marine sediments are suitable to be used as secondary raw materials in ceramic tiles and bricks production.

Phase evolution and microstructural characterization of sintered ceramic bodies from contaminated marine sediments, Journal of the European Ceramic Society, 29 (2009) 15-22; doi:10.1016/j.jeurceramsoc.2008. AbstractThe phase evolution during firing of ceramic bodies from three different contaminated marine sediments was investigated as a function of temperature. The mineralogical evolution examined by X-ray diffraction (XRD) revealed that quartz, which is a main crystalline phase in the original marine sediments, remains as a main phase in the sintered bodies. In addition, a glassy phase and new crystalline phases appear as result of different chemical reactions during firing. Scanning electron microscopy (SEM) showed a homogeneous microstructure composed by pores, crystals and a ceramic matrix. Energy X-ray dispersive spectroscopy (EDS) analyses permitted to distinguish the crystalline phases previously identified by XRD and also minor phases, which were not detected in the X-ray diffractograms.