Abstract
An attempt has been made to study the effect of coal quality on the reduction kinetics of iron ore–coal composite pellets under non-isothermal condition in inert atmosphere. During non-isothermal reduction of composite pellets, it is observed that (i) reduction rate of iron oxide increases with increasing temperature, (ii) reduction rate increases with increase in porosity of pellets and (iii) the computed values of activation energy (E) are lower during the initial stage of reduction (0.86–8.82 kJ mol−1) than those in the later stages of reduction (12.37–38.32 kJ mol−1). These values indicate that the initial stage reduction is controlled by gaseous diffusion mechanism and at final stage, mixed control reaction mechanism (i.e., both gaseous-diffusion and chemical reaction) is the rate controlling step. The present investigation aims at to assess the effect of Fetot/Cfix ratio in pellet, volatile matter in coal, and temperature on the reduction kinetics of iron ore–coal composite pellets using simultaneous thermogravimetric and differential thermal analyser (TG–DTA).
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Abbreviations
- A :
-
Pre-exponential factor (s−1)
- E :
-
Activation energy (kJ mol−1)
- F :
-
Fraction of reduction
- f wl :
-
Fractional weight loss
- f coal :
-
Fraction of coal present in composite pellet
- f vm :
-
Fraction of volatile matters present in coal
- f vr :
-
Fraction of volatiles released during reduction at a particular temperature
- f ore :
-
Fraction of ore present in composite pellet
- ρ ore :
-
Purity of iron oxide (Fe2O3)
- f o :
-
Fraction of oxygen present in Fe2O3
- k :
-
Rate of reduction or rate constant (s−1)
- R :
-
Gas constant (kJ mol−1 K−1)
- t :
-
Time (s)
- T :
-
Temperature (K)
- α:
-
Degree of reduction
References
Dutta S K, and Ghosh A, Metall Mater Trans 25B (1994) 15.
Ghosh A, in Proc. Int. Conf. on ‘Alternative Routes of Iron and Steelmaking’, Perth, Australia, September 1999, p 71.
Mantovani M C, Takano C, and Buchler P M, Ironmaking Steelmaking 29 (2002) 257.
Prakash S, Ironmaking Steelmaking 21 (1994) 237.
Sarkar S B, Ray H S, and Chatterjee I, J Therm Anal 35 (1989) 2461.
Seaton C E, Foster J S, and Velasco J, Trans Iron Steel Inst Jpn 23 (1983) 490.
Ansari Q A K, Ahier S J, Singer A R E, Ironmaking Steelmaking 11 (1984) 237.
Sharma T, Int J Miner Process 39 (1993) 299.
Huang B H, and Lu W K, Iron Steel Inst Jpn Int 33 (1993) 1055.
Wang Q, Yang Z, Tian J, Li W, and Sun J, Ironmaking Steelmaking 25 (1998) 443.
El-Geassy A A, Khedr M H, Nasr M I, and Aly M S, Ironmaking Steelmaking 28 (2001) 237.
Santos D M, and Maurao M B, Scand J Metall 33 (2004) 229.
Dutta S K, Trans Ind Inst Met 58 (2005) 801.
Sohn I, and Fruehan R J, Metall Mater Trans 36B (2005) 605.
Sohn I, and Fruehan R J, Metall Mater Trans 37B (2006) 223.
Sah R, Characterization of Cold Bonding and Fundamental Studies on Reduction Smelting of Iron Ore-Coal Composite Pellets, Ph D Thesis, Metallurgical and Materials Engineering Department, M.S. University of Baroda, Vadodara, India (2008).
Wen C Y, and Dutta S, in Coal Conversion Technology, (eds) Wen C Y, and Stanley Lee E, Addison-Wesley Publishing Co. Inc., Reading (1979), p. 57.
Smoot L D, and Smith P J, Coal Combustion and Gasification’, vol. 37, Planum Press, New York (1985).
Cypres R, and Soudan-Moinet C, FUEL 60 (1981) 33.
Cypres R, and Soudan-Moinet C, FUEL 59 (1980) 48.
Wang Q, Yang Z, Tian J, Li W, and Sun J, Ironmaking Steelmaking 24 (1997) 457.
Biswas A K, Principles of Blast Furnace Ironmaking’, 1st Indian Edition, SBA Publication, Calcutta (1984), p. 136, 220.
Dutta S K, and Ghosh A, ISIJ Int 33 (1994) 1168.
Ghosh A, and Chatterjee A, Iromnaking and Steelmaking (Theory and Practice),, First edition, PHI Learning Pvt. Ltd., New Delhi (2008).
Goswami M C, Prakash S, and Sarkar S B, Steel Research 70 (1999) 41.
Jiang T, Qui G, Xu J, Zhu D, and Singh R, Direct Reduction of Composite Binder Pellets and Use of DRI, Electrotherm (India) Ltd., Ahmedabad (2007).
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Sah, R., Dutta, S.K. Kinetic Studies of Iron Ore–Coal Composite Pellet Reduction by TG–DTA. Trans Indian Inst Met 64, 583–591 (2011). https://doi.org/10.1007/s12666-011-0065-x
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DOI: https://doi.org/10.1007/s12666-011-0065-x