Properties of sinter produced from mini-pellets consisting of coarse iron ore particles and adhering fine mixtures having quaternaly calcium ferrite composition

A wide range of sintering experiments were carried out in order to use a large quantity of fine iron ore for the sintering process and to improve the properties of product sinter. Modeled mini-pellets (named duplex pellets) which consisted of coarse iron ore particles as cores and fine mixture, of which chemical composition was specified to a quaternary (CaO-SiO₂-Al₂O₃-Fe₂O₃) calcium ferrite, as shell layer were used in the present experiments. The effect of ratio of shell in pellet and of iron ore characteristics on the sintering process and metallurgical properties of the product sinter were examined. The maximum bed temperature decreased with increasing ratio of shell in pellet from 50 to 80 mass%. Reduction degradation property of product sinter was improved with increasing ratio of shell in pellet. When the ratio of shell was 80 mass%, reduction degradation property of product sinter was improved by the use of fine iron ore with good reactivity with limestone.