Statistical optimisation parameter for lean grade self-reducing nuggets by surface response modelling to produce pig iron

Abstract

Iron ore fines, lean grade coal and coke dust fines have always challenged the metallurgists to develop a suitable process for its optimum use. The aim of this study is to utilise the inferior quality of iron ore fines, coal and plant waste coke dust for reduction. At first mechanical properties of iron ore nuggets are assessed through shatter and abrasion test and subsequent to which cold bonded self-reducing nuggets are directly reduced in standard reducing furnace. The maximum extent of reduction achieved in the present study is 87.2%. The reduced specimens are further characterised using XRD, SEM, EDX and chemical analysis method. Finally, the statistical model of Box Behnken Design (BBD) method is successfully utilised to optimise the process parameter for reduction experiments. The optimised sample thus obtained is subjected to melting for laboratory scale pig iron production. Better slag metal separation is achieved when calcined lime is used as a flux. The microstructure of the metallic iron is studied and it shows ferrite phase with dispersed carbon.

Keywords

Iron nuggets Solid state reduction Extent of reduction Box Behnken Design (BBD)Melting

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References

Biswas,

, Chakraborty,

, Chaudhuri,

M. G.

, Banerjee,

P. C.

, Mukherjee,

and Dey,

2013. Optimization of process parameters and dissolution kinetics of nickel and cobalt from lateritic chromite overburden using organic acids. Journal of Chemical Technology and Biotechnology, 89, (10), pp.1491–1500. doi: 10.1002/jctb.4288

Energy watch group coal: resources and future production EWG-Final-Version 28032007 Paper no 1/07, 10 July 2007, pp.1–47.

Gojic,

and Kozuh,

2006. Development of direct reduction process and smelting reduction for the steel production, Development of Reduction Processes for the Steel Productioni. Kem Industries, 55, (1), pp.1–10.

Gray,

R. J.

and Devanney,

K. F.

1986. Coke carbon forms: microscopic classification and industrial applications. International Journal of Coal Geology, 6, (3), pp.277–297. doi: 10.1016/0166-5162(86)90005-4

Indian Bureau of Mines. 2013. Geological survey of India Production of iron ore lumps fine concentrates in India (source MNI 01 04 2013)

Ishikawa,

, Kopfle,

, Mcclelland,

and Ripke,

2008. Rotary hearth furnace technologies for iron ore and recycling applications. Midrex Technologies Inc, 53, (2), pp.440–445.

Jozwiak,

W. K.

, Kaczmarek,

, Maniecki,

T. P.

, Ignaczak,

and Maniukiewicz,

2007. Reduction behavior of iron oxides in hydrogen and carbon monoxide atmospheres. Applied Catalysis A: General, 326, pp.17–27. doi: 10.1016/j.apcata.2007.03.021

Kumar,

and Patel,

2009. Mineral processing & extractive metallurgy, “Assessment of reduction behaviour of hematite iron ore pellets in coal fines for application in sponge ironmaking”. Mineral Processing and Extractive Metallurgy Review, 30, pp.240–259. doi: 10.1080/08827500802498215

Li,

Y.-J.

, Sun,

Y.-S.

, Han,

Y.-X.

and Gao,

2013. Coal-based reduction mechanism of low-grade laterite ore. Transactions of Non-ferrous Metals Society of China, 23, pp.3428–3433. doi: 10.1016/S1003-6326(13)62884-8

10.

Moura,

and Cyrotakano,

2010. Self-reducing pellets for ironmaking reaction rate and processing. An International Journal of Mineral Processing and Extractive Metallurgy Review, 24, (3–4), pp.183–202. doi: 10.1080/714856821

11.

Markotic,

, Dolic,

and Trujic,

2002. State of the direct reduction and reduction smelting processes. Journal of Mining and Metallurgy, 38, (3-4B), pp.123–141. doi: 10.2298/JMMB0204123M

12.

Narcin,

, Aydin,

, Sesen,

and Dikec,

1995. Reduction of iron ore pellets with domestic lignite coal in a rotary tube furnace. International Journal of Mineral Processing, 43, pp.49–59. doi: 10.1016/0301-7516(94)00045-2

13.

Ohrbach,

K. H.

, Klusmeler,

and Kuttrup,

1984. Tg-Dta-Ms investigation of coal, and characterization of the volatile product released as a function of temperature. Journal of Thermal Analysis, 29, pp.147–152. doi: 10.1007/BF02069950

14.

QaisarȦ,

S. H.

and Ahmad,

M. A.

2014. Production, consumption and future challenges of coal in India. International Journal of Current Engineering and Technology, 4, (5), pp.3437–3440.

15.

Sen,

, Mukherjee,

and Dey,

2010. Effect of grading of chromite ores on the quality of briquettes. JISI, 50, pp.200–206.

16.

Stull,

R. L.

and Peapples,

2003. Coal analysis (proximate and ultimate) from the delta junction area, Alaska. Division of Geological & Geophysical Surveys, Raw-Data file 2003-1.

17.

Tekindal,

M. A.

, Bayrak,

, Ozkaya,

and Genc,

2012. Box-Behnken experimental design in factorial experiments: the importance of bread for nutrition and health. Turkish Journal of Field Crops, 17, (2), pp.115–123.

18.

Yakarelbeyli,

, Piskin,

and Sutcu,

2004. Pyrolysis kinetics of Turkish bituminous coals by thermal analysis. Turkish Journal of Engineering and Environmental Sciences, 28, pp.233–239.