Coke for iron making

Abstract

Coke quality in blast furnace is measured by its resistance to degradation, in its role as a fuel, a reducing agent and also its role as a permeable medium. The degradation of coke takes place with its position in the furnace, the reactions taking place with different gases and also due to abrasion among various components of the burden. The coke quality is thus measured by its hot and cold strength which ultimately depends on types of coal in the blend, technology by which it is manufactured etc. Due to decreasing availability of high quality raw material and also increasing environmental pressure, understanding of the effect of coal properties on coke quality is highly essential to improve the efficiency of blast furnaces. The use of inferior grade coking coal/non-coking coal in coke making keeping improved blast furnace efficiency is the need for the day. The paper will focus on challenges and opportunities of coke making with inferior coal, cheaper cost by way of raw material and technology selection. Further it will demonstrate that conventional coal parameters like coal ranks, macerals, general coal chemistry are not sufficient to assess the coke performance in blast furnace. The influence of mineral matter, its reactions/transformations, the structural elements of coke etc, also impact on coke reactivity and hence on the performance of blast furnace.