Preparation and characterisation of environmental-friendly ceramsites from iron ore tailings and sludge

Abstract

ABSTRACT Ceramsites have been prepared from iron ore tailings and sludge by controlling the content of the iron ore tailings and sludge, and calcination parameters. Effect of the sintering temperature, duration time and content of the iron ore tailings on the physical properties of the ceramsites have been analysed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The optimal component of tailings/sludge ceramsites is as follows: Iron ore tailings 90 wt.%, sludge 10 wt.%. The optimal sintering parameters of the ceramsites are 1100°C for 30 min. The cylinder compressive strength of the obtained ceramsites is 10.1 MPa. XRD analysis shows that the ceramsites are composed of CaSiO3, Al2SiO5, MgSiO3, Ca7Si2P2O16, CaAl2Si2O8 and Ca2Fe2O5 phases. SEM observations show that the ceramsites consist of pore structure with a size of less than 50 μm. The volume of the ceramsites shrinks and the density increases, which remarkably increase the cylinder compressive strength with increasing the sintering temperature and duration time.