Strengthening Granulating and Sintering Performance of Refractory Iron Concentrate by Pre-Pelletizing

Abstract

May Concentrate Iron ore, as a refractory iron concentrate, deteriorates the permeability of the sintered layer during the sintering process due to its fine particle size and poor granulating performance. Therefore, it cannot be widely used in iron ore sintering. In this study, the strengthening granulation of May Concentrate Iron ore using pre-pelletizing to expand its utilization ratio was proposed. The experiments of conventional granulation, pre-pelletizing granulation and sinter pot test were carried out. Increasing May Concentrate Iron ore (a refractory iron concentrate) proportion was detrimental to conventional granulation, reducing the quasi-particle particle size and strength. May Concentrate Iron granulating and sintering performances were improved by pre-pelletizing. The quasi-particle average size at 36% May Concentrate Iron proportion jumped to 4.92 mm of pre-pelletizing granulation from 3.22 mm of conventional granulation. Meanwhile, the permeability index rose to 0.33 from 0.11, while the falling and drying pulverization ratio fell to 7.05% and 6.11% from 22.59% and 15.88%, respectively. The consolidation mode of matrix materials was liquid phase consolidation, while that of May Concentrate Iron pellets was solid phase consolidation, forming the structure of the pellets embedded in the matrix materials. Furthermore, the partial alkalinity of the matrix materials was increased because of the separation of May Concentrate Iron, generating a large amount of acicular calcium ferrite with better consolidation strength than conventional granulation sintering.