Abstract:In order to achieve the resourceful and large-scale utilization of high-iron red mud with high iron content, an innovative technique of short process was proposed to prepare ultra-lightweight ceramsite from high-iron red mud. The effects of raw material dosages on the bulk density, water absorption rate, expansion index and compressive strength of ultra-lightweight ceramsite were systemically investigated, and the corresponding raw material dosages were also derived. The results indicate that increasing the proportion of bentonite and high-iron red mud can significantly enhance the compressive strength of ceramsite, but deteriorates its expansion performance. However, increasing the proportion of silica can increase the viscosity of liquid phase during sintering and improve the expansion performance of ceramsite. When the mass ratios of high-iron red mud, bentonite and silica is 5︰1︰4, the bulk density, expansion index, water absorption rate, and compressive strength of the ultra-lightweight ceramsite is 328 kg/m3, 291%, 7.21%, and 1.00 MPa, respectively.