The effect of mechanical activation on the carbothermic reduction kinetics of hematite-graphite mixture

Document Type: Research Paper

Authors

Department of Materials Engineering, Isfahan University of Technology, Isfahan 8415683111, Iran.

Abstract

The effect of mechanical activation on structural changes and kinetics of carbothermic reduction of hematite with graphite was studied in this research. Hematite powder mixture with graphite (with stoichiometry ratio C/O=1) was milled for the time periods of zero to 50 hours, and the structural changes were studied using X ray diffraction (XRD). The effect of mechanical activation on the kinetics of hematite carbothermic reduction was studied by performing thermal analysis tests and by employing model-free and constant slope methods. The activation energy as well as the reaction mechanism was then determined. The results showed that by mechanical activation for a time period of 50 h, the activation energy is decreased from 387 kJ/mol-1 to 186 kJ/mol-1, and the starting temperature of the reaction is decreased from 1125 to 620°C. The Boudouard chemical reaction was determined as the rate controlling step.

Keywords


[1] Y. Kashiwaya and K. Ishii: ISIJ Int., 44 (2004), 1981.
[2] Y. Kashiwaya, M. Kanabe and K. Ishii: ISIJ int., 46 (2006), 1610.
[3] J. V. khaki, K. Ishii and H. Suzuki: ISIJ int., 42 (2002), 13.
[4] Y. Kashiwaya, , H. Suzuki and K. Ishii: ISIJ int., 44 (2004), 1970.
[5] J. Yang, T. Mori and M. Kuwabara: ISIJ int., 47 (2007), 1394.
[6] J. V. Khaki, M.R. Aboutalebi and S. Raygan: Mineral Proc. Extract. Metall., 25 (2004), 29.
[7] Y. Iguchi and Y. Takada: ISIJ Int., 44 (2004), 673.
[8] I. Seki and K. Nagata: ISIJ Int., 46 (2006), 1.
[9] Y. Kashiwaya, H. Susuki and K. Ishii: ISIJ Int., 44 (2004), 1975.
[10] Y. Kashiwaya, Y. Yamaguschi, H. Kinoshita and K. Ishii, ISIJ int., 47 (2007), 226.
[11] S. K. Dey, B. Jana and A. Basumallick: ISIJ int., 33 (1993), 735.
[12] S. Raygan, J. V. Khaki and M.R. Aboutalebi: Mater. Synth. Proc., 10 (2002), 113.
[13] G.M. Chowhhury and G.G. Roy: Comp. Mater. Sci., 45(2009), 176.
[14] S.D. Genieva, L.T. Vlaev and A.N. Atanassov: J. Therm. Anal. Calorim., 99 (2010), 551.
[15] N.S. Varandecic, M. Erceg, M. Jakic and I. Klaric: Thermochim. Acta., 498 (2010), 71.
[16] J. V. Khaki, M. Panjepour, Y. Kashiwaya, K. Ishii and M. S. Bafghi: Steel Res. int., 75 (2004), 169.
[17] P. Pourghahramani and E. Forssberg: Int. J. Miner. Process., 82 (2007), 96.
[18] V.H. Grohn, R. Paudert and H. Friedrch: Zeitschrift fur anorganische und allgemeine Chemie Band, 384 (1966), 21.
[19] S. Nath: Metall. Matr. Eng., (2009).
[20] S. Ueda, K. Yanagiya, K. Watanabe, T. Murakami, R. Inoue and T. Ariyama: ISIJ int., 49 (2009), 827.
[21] R. Tahmasbi, M. Shamanian, M. H. Abbasi and M. Panjepour: J. Alloys Compd., 472 (2009), 334.
[22] M. Zdujic, C. Jovalekic, Lj. Karanovic and M. Mitric: Mater. Sci. Eng. A, 262 (1999), 204.
[23] M. Zdujic, C. Jovalekic, Lj. Karanovic, M. Mitric, D. Poleti and D. Skala: Mater. Sci. Eng. A, 245 (1998), 109.
[24] S.C. Tjong and H. Chen: Mater. Sci. Eng. R, 45 (2004), 1.
[25] D. Oleszak, A. Olszyan: Proc. of the XVIII Applied Crystallography Conference, Wisla, Poland, (2000), 39.
[26] M. Erceg, T. Kovacic and S. Perinovic: Thermochim. Acta, 476 (2008), 44.
[27] S. Vyazovkin and C.A. Wight: Thermochim. Acta, 340-341 (1999), 53.
[28] P. Pourghahramani and E. Forssberg: Thermochim. Acta, 454 (2007), 69.
[29] T. Ozawa: A New Method Of Analyzing Thermogravimeteric Data, 11 (1965), 1881.
[30] H. Kissinger: Analytical Chemistry National, Bureau of Standards, Washington, D. C. 29 (1957), 1072.
[31] A. Maleki, M. Panjepour, B. Niroumand and M. Meratian, J. Mater. Sci., (2010).
[32] B. Jankovic, B. Adnadevic and J. Jovanovic: Thermochim. Acta, 452 (2007), 106.
[33] B. Boonchom and S. Puttawong: Physica B., 405 (2010), 2350.
[34] Q. Shu, J. Liu, J. Zhang and M. Zhang: Metal., 13 (2006), 1.
[35] R. Padilla, M.C. Ruzi and H.Y. Sohn: Metall. Mater. Trans. B, 28 (1997), 265.