Improving Sinter Consolidation Characteristics of Nickel Laterite by Using a Low-Melting Additive in Hybrid Sintering Process

Sinter indices of limonitic nickel laterite are very poor due to the large loss on ignition and high formation temperature of liquid phase. For the better sinter consolidation characteristics of limonitic nickel laterite, the hybrid sintering technology was applied and a low-melting additive was added in the sintering process. The synergistic action of the two factors contributes to the formation of liquid phase and the improvement of sinter bed permeability. A tighter sinter microstructure is formed with the much lower porosity and higher SFCA (silico-ferrite of calcium and aluminum) amount. Consequently, sinter indices are greatly improved with tumble index and productivity increased by 35.01% and 26.80% and solid fuel rate reduced by 35.30%. In addition, the average size of product sinter is increased from 14.72 mm to 22.73 mm compared with the base case. Metallurgical properties of product sinter are excellent with reduction index and reduction degradation index (RDI_+3.15) of 81.56% and 95.36%.