Influence of different MgO coating methods on preventing sticking during reduction of Fe2O3 particles in a fluidized bed

Coating MgO can inhibit sticking effectively during iron ore reduction in a fluidized bed, in order to explore the functional mechanism of coating, different MgO coating methods (briquetting-sintering method, high temperature injection method, powder method, slurry-sintering method) were tried in this experiment. The metallization ratio (MR) of the product increased slightly with the increase of the coating amount when the coating amount was below 1wt%. When the coating amount surpassed 1wt%, 3600 seconds of fluidization time and 95% of metallization ratio were achieved without sticking happening. The fundamental reason for inhibiting particle agglomeration was proved to be the formation of MgO center dot Fe2O3 after coating MgO, which caused surface modification of Fe2O3 particles during high temperature reduction process. That makes changes on the accumulation and growth characteristics of the new generating iron, then reduces the viscosity of the particles surface. Meanwhile, the relation between the coating effect and the coating mechanism is analysed in this work. (C) 2015 The Authors. Published by Elsevier Ltd.