Lishun Yuan

Structure Model of Granules for Sintering Mixtures

Structure model of granules, boundary value of nucleus and powder, and the relationship between granulation efficiency and boundary value were investigated. Granules of sintering mixtures are composed of adhesive powder and nucleus. In the mixtures, particles larger than 1. 00 mm act as nucleus and particles smaller than 0. 25 mm act as adhesive powder. Particles with size between 0. 25 – 1. 00 mm can be adhesive powder as well as nucleus depending on the granulation conditions. When the boundary value is close to 0. 25 mm, the granulation efficiency is lower than 50%. When the boundary value is close to 1. 00 mm, the granulation efficiency is above 90%. The boundary value is influenced by the iron ore type, granulation moisture, fineness of raw materials and burnt-lime activity. Good adhesive capability, suitable moisture content, appropriate particle size distribution and high burnt-lime activity make the boundary value move towards 1. 00 mm and improve the granulation efficiency.

Effect of H2O(g) Content in Circulating Flue Gas on Iron Ore Sintering with Flue Gas Recirculation

The influence of H2O (g) content in circulating flue gas on sintering was studied by simulating the flue gas circulating sintering. The results show that the burning speed of solid fuel and the heat transfer rate during sintering process are improved when the H2O (g) content increases from 0 to 6%, which accelerates the sintering speed. However, when the H2O (g) content exceeds 6%, the over-wet zone in sinter bed is thickened, which deteriorates the permeability of sintering bed. In addition, the magnetite content in sinter increases, while the acicular calcium ferrite content decreases. Accordingly, the sinter yield and tumble index decrease with excessive H2O (g) content. To guarantee the yield and quality of sinter, the favourable H2O (g) content in circulating flue gas should be controlled to be less than 6%.