Structural Characteristics of Active Quicklime Flux and Optimization of Quasiparticle Granulation Performance in Thick-Bed Sintering

Abstract

The deterioration of sintering bed permeability is an important factor that hinders thick-bed sintering. Flux is one of the key factors that determines the bonding degree of quasiparticles. Selecting high-quality flux is an effective way to improve both the permeability and thickness of the sintering bed. Herein, the hydration activity of quicklime flux is used as a criterion to assess quality. Two types of quicklimes with different activity levels are selected for comparative analysis in three aspects: microstructure, sinter quasiparticle granulation performance, and the sinter mineralization process. The experimental results show that active quicklime has a higher CaO content and fewer impurities. The small and dense CaO particles give active quicklime significant advantages in raw material granulation and sinter mineral formation. The application of active quicklime can effectively improve the permeability of the sintering bed; notably, the drying fines’ removal rate decreases from 22.81% to 2.42% with an increase in the ratio of active quicklime addition. However, this affects the average particle size of quasiparticles. To address this issue, solutions are determined by adjusting the condition parameters. It is concluded that active quicklime plays an important role in enhancing the permeability of the sintering bed during thick-bed sintering production.