Carbonization Study of Non-Coking Coals and Characterization of Their Properties for Application in DRI Production

Abstract

There is scarcity of coking coal reserve in India. Only 15% coking coal is coking in nature. As Coking coal is costly, there arrives a need to find an alternative route for iron making. India is the world's biggest maker of DRI. The majority of which is delivered primarily through the coal based method of production. Growth in the DRI production can be attributed largely to the popularity of secondary steelmaking route, which has shown a phenomenal growth in India. This has been mainly because of the low investment cost of the Electric Arc Furnace (EAF) as compared to the integrated blast furnace-oxygen converter route and because of its better flexibility of product mix. The future of coal based sponge iron industry in India is bright because of huge availability of non –coking coal (85% of the total coal found). We are selecting different non-coking coal samples from various mines of Odisha to study and evaluate the effect of different carbonization temperatures on the physical, chemical properties, calorific value, reactivity, and caking index of the coal samples. . Present investigation deals with the study of physical and chemical properties of non- coking coal samples. The results indicated that the physical and chemical properties of coal depend on the carbonization temperature, heating rate and soaking time. It has been found that ash content and fixed carbon content increases while calorific value and volatile matter decreases as the carbonization temperatures rises from 400°C to 1000° C. It is also found that coal chars reactivity towards CO2 decreases as the carbonization temperature rises from 400°C to 1000° C. Apparent porosity increases up to 400°C and decreases thereafter as the carbonization temperature increases up to 1000°C, while apparent density shows contradictory effect of apparent porosity. Lingraj coalmine showed higher fixed carbon content, calorific value and coal grade as compared to other coalmines. Reasons to carry out this work is to search good quality of coal for DRI plants.