The morphology of iron and agglomeration behaviour in the reduction progress of iron oxide fines were investigated in terms of isothermal reduction at 800 °C in an atmosphere of CO and H2. Agglomeration index was employed to evaluate the agglomeration behaviour during reduction. Sticking and agglomeration occurred regardless of the iron oxides and reducing atmosphere. Reduction by CO showed a higher tendency for sticking due to the formation of iron whiskers. The addition of CaO and MgO to Fe2O3 in sintering process could improve the reduction, and also decrease the sticking by forming calcio/magnesio-wustite on the surface. Iron whiskers were still formed with the addition of CaO and MgO, and the shape of whiskers were different from that of pure Fe2O3. Uniform coating layer on the surface of particles might be one of the important factors affecting the decrease in sticking between particles.
Keywords Morphology of iron · Agglomeration · Sticking · Iron whiskers · Calcio/magnesio-wustite · Coating