December 2011 - SIMA
December 2011 - SIMA 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
Parameters Pellets Iron oreArya Ardent Ispat Godawari JSPL Essel mining(Barbil) (Keonjhar) (Raipur) (Raigarh) (Orissa)% Fe(T) 64.46 64.09 63.39 63.40 65.35% LOI 0.36 0.51 0.22 0.20 1.55% SiO3.87 4.03 4.72 4.64 1.962% Al2O2.08 2.13 2.68 2.58 1.833% CaO 0.71 0.68 0.86 0.72 -% MgO 0.22 0.21 0.39 0.32 -% Phos 0.049 0.047 0.046 0.041 -Tumbler index 93.25 94.12 92.11 92.00 88.00% RDI (-3mm)(After reduction) 6.68 N.A. N.A. N.A. 22.24% Reducibility 73.81 N.A. N.A. N.A. 66.34% Porosity 19.00 18.00 20.00 – 24.00 20.00 – 24.00 -CCS (Kg/Pellet) 250 210 220 250 -Size (mm) 5-18 8-18 5-18 8-16 5-18It is obvious from above data that quality of Pellets ingeneral is inferior to Iron ore used earlier. Moreoverit requires higher temperature and comparativelymore coal even at lower feed rate for making DRI inKilns.THEORETICAL CONSIDERATIONS:-Principally, induction furnaces are melting units ofcharge mix with electrical power as source of heat.As it is having SiO lining, no flux addition is done in2the furnace. Only DRI Pellets and C.P.C. are chargedintermittently during the process.Main chemical reaction taking place is :FeO + C = Fe + CO ↑(gas) Δ H° = 36.16 K.Cal.CO gas evolves and passes through slag, causesboiling of the bath. As a result, the slag becomesfoamy, its density goes down. It floats at the top andis removed continuously. It is very important thatboiling phenomenon should be optimum - it shouldneither be less nor high for smooth operation offurnace. ‘C’ content is to be optimized by intermittentaddition of CPC but, optimum FeO is to be madeavailable through sponge iron as source of oxygenin this process. In case of DRI Pellets (A grade) whilecharged in the furnace, it was observed that slagbecame very thick and hence, it formed an umbrellaover the metal.Under such situation, slag removal became verydifficult leading to adverse furnace performance.DECEMBER-2011/17
- Page 3 and 4: CHAIRMAN’S MESSAGEI am happy that
- Page 5 and 6: Target Setting:The methodology for
- Page 7 and 8: Energy conservation Opportunities i
- Page 9 and 10: MXCOL ® : A BREAKTHROUGH IN COAL-B
- Page 11 and 12: MIDREX ® Direct Reduction PlantThe
- Page 14 and 15: IRON ORE PELLETS AS THE FUTURE META
- Page 16 and 17: Raw material availability:Basic raw
- Page 20 and 21: AVERAGE PERFORMANCE PARAMETERS:Sl.
- Page 22 and 23: CONCLUSION:The salient features of
- Page 24 and 25: HARI MACHINES JOINS HANDS WITH RAFA
- Page 26 and 27: Indian Reference of RafakoSA - Pola
- Page 28 and 29: DECEMBER-2011/26
- Page 30 and 31: e maintained while taking advantage
- Page 32 and 33: Plant Upgrades Reference ListPlant
- Page 34 and 35: TRI-FLO ® :-THE NEW GENERATION MUL
- Page 36 and 37: The ability of the Tri-Flo ® to be
- Page 38 and 39: Rejects re-cleaning with a 700 mm I
- Page 40 and 41: GREEN FIELD STEEL PROJECT OF JSPLJS
- Page 42: DECEMBER-2011/40
Parameters Pellets Iron oreArya Ardent Ispat Godawari JSPL Essel mining(Barbil) (Keonjhar) (Raipur) (Raigarh) (Orissa)% Fe(T) 64.46 64.09 63.39 63.40 65.35% LOI 0.36 0.51 0.22 0.20 1.55% SiO3.87 4.03 4.72 4.64 1.962% Al2O2.08 2.13 2.68 2.58 1.833% CaO 0.71 0.68 0.86 0.72 -% MgO 0.22 0.21 0.39 0.32 -% Phos 0.049 0.047 0.046 0.041 -Tumbler index 93.25 94.12 92.11 92.00 88.00% RDI (-3mm)(After reduction) 6.68 N.A. N.A. N.A. 22.24% Reducibility 73.81 N.A. N.A. N.A. 66.34% Porosity 19.00 18.00 20.00 – 24.00 20.00 – 24.00 -CCS (Kg/Pellet) 250 210 220 250 -Size (mm) 5-18 8-18 5-18 8-16 5-18It is obvious from above data that quality of Pellets ingeneral is inferior to Iron ore used earlier. Moreoverit requires higher temperature and comparativelymore coal even at lower feed rate for making DRI inKilns.THEORETICAL CONSIDERATIONS:-Principally, induction furnaces are melting units ofcharge mix with electrical power as source of heat.As it is having SiO lining, no flux addition is done in2the furnace. Only DRI Pellets and C.P.C. are chargedintermittently during the process.Main chemical reaction taking place is :FeO + C = Fe + CO ↑(gas) Δ H° = 36.16 K.Cal.CO gas evolves and passes through slag, causesboiling of the bath. As a result, the slag becomesfoamy, its density goes down. It floats at the top andis removed continuously. It is very important thatboiling phenomenon should be optimum - it shouldneither be less nor high for smooth operation offurnace. ‘C’ content is to be optimized by intermittentaddition of CPC but, optimum FeO is to be madeavailable through sponge iron as source of oxygenin this process. In case of DRI Pellets (A grade) whilecharged in the furnace, it was observed that slagbecame very thick and hence, it formed an umbrellaover the metal.Under such situation, slag removal became verydifficult leading to adverse furnace performance.DECEMBER-<strong>2011</strong>/17
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