December 2011 - SIMA

ore also could be intended to generate positivesentiment about availability of raw material forpelletization of ore dust. Due to non-availability oftechnology in India in the past, on the other handeasy availability of alternative better grade ore,requirement of large capital expenditure and overallcommercial viability was pushing the investment sofar but now all steel giants are finding opportunity inthat venture.Proper selection of iron ore and prior beneficiation ofthe dust ore to remove impurities including ganguecontent would result in producing very good pelletproduct to compete with good quality lumps forproduction of sponge iron at a comparatively lowercost.Other Benefits of pellets in comparison withnormal ore lumps could be listed as under:uuuHigh iron content and high degree of metallizationUniform size makes it easy to operate with, lessaccretion deposit in kilnsComparable purity : 63 – 68% iron, mainly Fe2O3u High tumbler Index : +95uuHigh porosity of 25-30% facilitate fast reductionand high metallization rateEnough bond strength – prevents generation offines/dust in rotary kilnsu Cost-effective – Coal consumption less by 15%,campaign life increases by 100%, longerrefractory life, low fines generation.ueasy availabilityProcess Development for use of Ore Pellets inInduction Furnace at Monnet Ispat :MIEL is presently the second biggest coal basedsponge iron producer in the country, have been usingaverage to good quality iron ores from Essel mining,Rungta mines and NMDC by proper blending alongwith good quality coal from captive Millupara minesin the rotary kilns to produce premium grade spongeiron and this DRI product is being used as metalliccharge along with some small quantity scrap in steelmaking in induction furnaces.Monnet Ispat & Energy Ltd., Raipur plant started steelproduction initially through captive coal based DRI–IF-CCM route in 1994 with a capacity of 2 Lac MTper annum. Due to intermediate crisis with respectto availability of quality iron ore MIEL, Raipur for thefirst time within industry put to trial to use A gradeDRI Pellets for steel making from Nov. 2008 ininduction furnaces. It was observed that the processphenomena was quite different and, posing a numberof operational difficulties as well as performanceproblems. These constraints were mainly due tochange in the quality characteristics of DRI Pelletsover iron ore DRI. Investigations were done andcorrective measures were taken to resolve theseproblems successfully. So it can be said that MIEL,Raipur became pioneer in the field of using coalbased DRI Pellets extensively through inductionfurnace route for steel making.Economic opportunity for Pellet as substitution:Steep rise in the prices of iron ore and Pig iron overthe past four five years, steel production processthrough electric furnaces was not left with much ofchoice to alternatively selecting commercially viableraw material but found alternative prospect in the formof iron ore pellet and gradually switched over toPellets for DRI making in the recent past. In generalraw material for Pelletization so far the manufacturershave been using are of lower grade iron ore, whichgenerally goes as a waste. Now with a view to utilizethis low cost item, Pelletization units are coming upin large scale and Pellet is expected to be the futurefeed material for DRI making. But Pellets beingmanufactured without beneficiation of fine ore arenot of good quality due to high content of gangueand lower Fe content generally pose seriousproblems in steel making through IF and strongobjection from prospective users.Under such situation MIEL, Raipur also purchasediron ore Pellets from various sources for making DRIon trial basis and started using it gradually inenhanced proportion for steel making. Typicalcomparative characteristics of these Pellets and ironore used are as follows:-DECEMBER-2011/16