Utilisation of sludge waste from water treatment for ceramic products

The influence of the additive of fresh water treatment sludge (WTS) on the physical and mechanical properties, structural parameters as well as mineralogical composition of the ceramic products is analysed in the research. It was determined that the main WTS component is amorphous Fe2O3 (approximately 70%). Size of WTS particles reaches up to 138 μm. Formation masses were prepared by incorporating from 5% to 40% of WTS additive and by burning out at the temperature from 1000 °C to 1050 °C. Investigation showed that the physical and mechanical properties of the ceramic bodies vary depending on the amount of WTS additive incorporated: density, relative wall thickness of the pores and capillaries, compressive strength decrease, water impregnation and effective porosity increase. It was found that WTS additive, which is mostly composed from colorific Fe2O3, can be utilised as a natural pigment that dyes the ceramic body in darker, more intense red colour.