Conversion of Ferronickel Slag to Thermal Insulation Materials by Microwave Sintering: Effect of Fly Ash Cenosphere Addition

Abstract

The conversion of ferronickel slag (FS) to thermal insulation materials by microwave sintering in the presence of different additions of fly ash cenosphere (FAC) was studied. The results showed that adding proper amount of FAC could promote the generation of cordierite with low thermal conductivity during the sintering process, while the hollow spherical FAC facilitated the pore development and reduced the bulk density of thermal insulation materials. The thermal conductivity, bulk density, compressive strength, water absorption and linear shrinkage of the thermal insulation material were 0.328 W/(m·K), 1.45 g/cm3, 27.09 MPa, 23.48% and 7.74%, respectively, under the conditions of the mass ratio of FAC to FS of 1/3, sintering temperature of 890 °C, and sintering time of 20 min. This study represents a good example of clean and efficient value-added utilization of FS and other solid wastes.KeywordsMicrowave sinteringFerronickel slagFly ash cenosphereThermal insulation materials