CHARACTERISTICS OF INDIAN NON-COKING COALS AND IRON ORE REDUCTION BY THEIR CHARS FOR DIRECTLY REDUCED IRON PRODUCTION

Abstract

Studies on chemical and physical properties ( proximate analysis, sulphur content, reactivity, iron ore reduction potential, caking index and ash fusion temperatures) of coals, procured from sixteen different mines of Orissa, were undertaken for their judicial selection in Indian sponge iron plants. These coals were found to have low sulphur (range : 0.40 – 0.66 %) and moderate to high ash (range : 22 – 53 %) contents. The results indicated no caking characteristic in all the coals except Basundhara. Majority of the studied coal ashes were found to have higher fusion temperatures (ST: 1349 – 15470C; HT: 1500 – 16630C; and FT: 1510 – 17010C). An increase in fixed carbon content in the coal char, in general, led to decrease in its reactivity towards CO2, and majority of the chars exhibited significantly higher reactivities (> 4.0 cc of CO/g.sec). Further reduction studies in coal chars at 9000C indicated an increase in the degree of reduction of fired hematite iron ore pellets with increase of char reactivity and reduction time. The authors recommend the utilization of majority of the studied coals as such and some of them (Lakhanpur, Samleshwari, Orient OC– 4 and Dhera coals) after blending or beneficiation.