Mineralization Behavior and Strengthening Mechanism of Limonitic Laterite Ore Sintering Process Enhanced by Calcined Lime Coating

The dehydration process of limonitic laterite ore consumes a lot of heat, which seriously affects the sintering performance and increases the solid fuel consumption of sintering. In this paper, the sintering performance and mechanism of limonitic laterite ore strengthened by a coating with calcined lime was studied. The results show that, when the coating proportion of calcined lime increased from 0% to 100%, the yield, tumble strength, and utilization coefficient of the sinter increased by 14.55%, 24.17%, and 20.43%, respectively, and the solid fuel consumption decreased by 13.47%, which means that CO2 emissions were significantly down. Mineralogical analysis shows that the microstructure of the sinter was significantly improved by the calcined lime coating. The structure of the sinter changed from large-pore thin-walled to small-pore thick-walled and the porosity decreased from 43.47% to 30.12%, which means that the sinter structure was more densified. The grain size of hercynite grew markedly and the content of silico-ferrite of calcium and aluminum (SFCA) in the liquid phase increased significantly, with the SFCA expanding from the outside to the inside, forming an interwoven structure with the spinel phase, the strength of the sinter was significantly improved. This study provides an effective technology for a high-quality sintering process of limonitic laterite ore.