Thermal, physical, mechanical and microstructural properties of dredged sediment-based ceramic tiles as substituent of kaolin

Abstract

The aim of this study was to recycle dredged sediments as an alternative raw material in the production of ceramic tiles. The effect of the substitution of kaolin by raw sediment (HDS) and calcined sediment (HDSC) in the mixture of the ceramic tile samples sintered at 1100 and 1200 °C was studied. The samples were prepared with different proportions of HDS and HDSC (0, 10, 20 and 30 wt.%) substituting kaolin. The mineralogical analysis of the samples shows that mullite phase disappears in the samples incorporating raw sediments (HDS) and fired sediments (HDSC) leading to the formation of new crystalline phases such as anorthite and diopside.Moreover, ceramic tile samples with 20 wt.% of calcined sediment improve its densification and hence the compressive strength (171 MPa) and thermal conductivity (0.555 W/mK). An evaluation of the leaching was carried out in the ceramic samples, finding that the concentrations of heavy metals in the leachate were within the safety limit established by the USEPA. The heavy metals were immobilised in the ceramic matrix. Therefore, the results showed that dredged sediment (HDS) and calcined sediment (HDSC) could be used as substituent of kaolin to produce eco-friendly ceramic building materials as floor tile ceramics.

Keywords: Ceramic tiles; Compressive strength; Dredged sediments; Leaching test; Thermal conductivity.