An efficient method for iron ore sintering with high-bed layer: double-layer sintering

Abstract

Poor permeability and low sintering productivity restrict the development of high-bed sintering. An efficient method of the double-layer sintering process (DLSP) was proposed to achieve high-bed sintering and solve the aforementioned problems. Theoretical calculation and sintering pot experiments were implemented to investigate the double-layer sintering process. Traditional sintering process and DLSP were compared in terms of sintering indices, metallurgical properties and morphology characterization. Under the condition of traditional sintering process, DLSP successfully realized fast velocity and highly productive sintering of 1000-mm high bed. After the sintering bed is charged and ignited twice, the air permeability of the bed has been greatly improved. Sintering time is shortened significantly by simultaneous sintering of the upper and lower feed layers. Under the condition of bed height proportion of 350/650 mm and pre-sintering time of 20 min, the yield, tumbler strength, productivity and solid fuel consumption are 69.96%, 65.87%, 1.71 t (m2 h)−1 and 56.71 kg/t, respectively. Magnetite, hematite, calcium ferrite and complex calcium ferrite are the main phases of DLSP products. The metallurgical properties of DSLP products meet the requirement of ironmaking. It indicates that DLSP is an effective method to solve the disadvantages of bad permeability and low sintering productivity in high-bed sintering.