Development of Production Process for Pre-reduced Agglomerates and Evaluation of Its Quality

To achieve the greatly decrease in CO(2) emission at iron making process, the production process of the pre-reduced agglomerates (the following: PRA), which are partially reduced simultaneously with agglomeration of iron ore on the existing sintering machine, was proposed. In this paper, the basic studies to produce PRA examined with the test pot and the results of estimations for using PRA as the main raw material of blast furnace were described. At the basic studies, the optimum conditions for producing PRA such as the particle size of coke as reducing agent, the structure of quasi-particles and the oxygen concentration in suction gas during sintering were examined. Then the maximum reduction degree of 40% was achieved for the PRA made from quasi-particles produced by tumbling granulation. Moreover the possibility of attaining reduction degree of 60% was confirmed for the PRA made from briquettes as raw material particles. Whereas it became obvious that prevention of generating excess melt caused by the disintegration of quasi-particle or briquette was indispensable. From the results of estimations to use PRA at blast furnace, the pressure drop in blast furnace was confirmed to decrease as compared with usual sintered ore, and the permeability in blast furnace was improved as the reduction degree of PRA was increased.