New Coal-based Process to Produce High Quality DRI for the EAF

Abstract

A new coal-based process to produce high quality DRI for EAF has been developed. This process is characterized by producing reduced iron directly from the mixture of fine ore and fine carbonaceous material, and by melting reduced iron to separate metal and slag in a rotary hearth furnace. The carbonaceous layer which has hollows on its surface is laid on the rotary hearth to make it possible to melt the reduced iron. A bench scale test was carried out to confirm the basic concept of the process. Quality of iron pebbles and productivity of the process were examined. The metal was obtained as iron pebbles without ash, gangue and micro-pores. These properties are desirable for EAF operation. The furnace temperature was one of the most important factors for the productivity. The productivity of a commercial plant with a capacity of 500, 000 ton per year was estimated using a one-dimensional, unsteady state mathematical model. The cost comparison of steelmaking using various iron sources was carried out. The steelmaking cost using iron source produced by this process was estimated to decrease by 18% compared with operation using 100% scrap. A bench scale test was also carried out for the treatment of BF dust after size separation.