Abstract
In the present study, the kinetics of removal of loss on ignition (LOI) by thermal decomposition of hydrated minerals associated with natural hematite iron ore has been investigated in a fixed bed system using isothermal methods of kinetic analysis. Hydrated minerals in these hematite iron ores are kaolinite, gibbsite and goethite, which contribute to the LOI during thermal decomposition. Experiments in fixed bed have been carried out at variable bed depth (16, 32, 48 and 64 mm), temperature (400–1200 °C) and residence time (30, 45, 60 and 75 min) for iron ore sample. It is observed that beyond a certain bed depth (16 mm), 100 % removal of LOI is not found to be possible even at higher temperature and higher residence time. Most of the solid-state reactions of isothermal kinetic analysis have been used to analyze the reaction mechanism. The raw data are modified to yield fraction reacted ‘α’ versus time and used for developing various forms of ‘α’ functions. The study demonstrates that decomposition of hydrated minerals associated with hematite ore is controlled either by chemical kinetics or nucleation or both. The estimated apparent activation energy values in all the experimental situations are found to be of the order of 70 kJ mol−1, reinstating that the reactions are indeed controlled by chemical kinetics.
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Das SK, Das B, Saktivel R, Mishra BK. Mineralogy, microstructure, and chemical compositions of goethites in some iron ore deposits of Orissa, India. Miner Process Extr Metall Rev. 2010;31:97–110.
Mishra BK, Reddy PSR, Das B, Biswal SK, Prakash S, Das SK. Issues relating characterization and beneficiation of low grade iron ore. Steel World. 2007;34–7.
Biswal SK, Utilization of low grade iron ore fines, slimes and tailings by physical beneficiation to minimize the waste generation. J Sustain Planet. 2010;1:46–58.
Bamford CH, Tipper CFH (Eds.) Comprehensive chemical kinetics, vol. 22, Chapter 22. Netherland: Elsevier Scientific Publishing Corporation; 1980.
Halikia I, Zoumpoulakis L, Christodoulou E, Prattis D. Kinetic study of the thermal decomposition of calcium carbonate by isothermal method of analysis. Eur J Miner Process Environ Protect. 2001; 1(2):1303–0868, 89–102.
Halikia I, Neou-Syngouna P, Kolitsa D. Isothermal kinetic analysis of the thermal decomposition of magnesium hydroxide using thermo gravimetric data. Thermochim Acta. 1998;320:75–88.
Garner WE, editor. Chemistry of the solid state. London: Butterworths Scientific Publications; 1955.
Watari F, Delavignette P, Van Landuyt V, Amelinckx S. Electron microscopic study of dehydration transformation. II. The formation of the superstructure on dehydration of goethite and diaspore. J Solid State Chem. 1983;48(49):417–27.
Goss CJ. The kinetics and reaction mechanism of the goethite to hematite transformation. Min Mag. 1987;51:437–51.
Wolska E. Relation between the existence of hydroxyl ions in the anionic substance of hematite and its infrared and X-ray characteristics. Solid State Ion. 1988;1349:28–30.
Ozdemir O, Dunlop DJ. Intermediate magnetite formation during dehydration of goethite. Earth Planet Sci Lett. 2000;177:59.
Przepiera K, Przepiera A. Kinetic of thermal transformations of precipitated magnetite and goethite. J Therm Anal Calorim. 2001;65:497–503.
Lopej FA, Ramirej MC, Pons JA, Lopez-Delgado A, Alguacil FJ. Kinetic study of thermal decomposition of low-grade nickeliferous laterite ores. J Therm Anal Calorim. 2008;94(2):517–22.
Rzepa G, Bajda T, Gawel A, Debiec K, Drewniak L. Mineral transmations and textural evolution during roasting of bog iron ores. J Therm Anal Calorim. 2015;. doi:10.1007/s10973-015-4925-1.
Diamandeseu L, Mihaila-Tabasanu D, Calogero S. Mater. Che. Phys. 1997;48:170.
Grygar T, Ruan IHD, Gilkes RJ. Re-examination of the kinetics of the thermal dehydroxylation of goethite. J Therm Anal Calorim. 1999;55:301–9.
Fan H, Song B, Li Q. Thermal behavior of goethite during transformation to hematite. Mater Chem Phys. 2006;98:148–53.
Masset P, Poinso JY, Poignet JC. TG/DTA/MS Study of the thermal decomposition of FeSO4·6H2O. J Therm Anal Calorim. 2006;83:457–62.
Morcos RM, Navrotsky A. Iron ore sintering characterization by calorimetry and thermal analysis. J Therm Anal Calorim. 2009;96(2):353–61.
Lima-de-Faria J. Dehydration of goethite and diaspore. Zeitschrift fur Kristallographie. 1963;119:176–203.
Pollack JB, Pitman D, Khare N, Sagan C. Goethite on Mars: a laboratory study of physically and chemically bound water in ferric oxides. J Gophyd Res. 1970;75:7480–90.
Thrierr-Sorel A, Larpin JP, Mougin G. Annal Chim. 1978;3:305–15.
Keller P. Neues Jahrb Mineral. Mh. 1978:115-27.
Prasad PSR, Shiva Prasad K, Krishna Chaitanya V, Babu EVSSK, Sreedhar B, Ramana Murthy S. In situ FTIR study on the dehydration of natural goethite. J Asian Earth Sci. 2006;27:503–11.
Perez-Maqueda LA, Criado JM, Sanchez-Jimenez PE, Dianez MJ. Applications of sample-controlled thermal analysis (SCTA) to kinetic analysis and synthesis of materials. J Therm Anal Calorim. 2015;120:45–51.
Gialanella S, Girardi F, Ischia G, Lonardelli I, Mattarelli M, Montagna M. On goethite to hematite phase transformation. J Therm Anal Calorim. 2010;102(3):867–73.
Inoue M, Kitamura K, Tanino H, Nakayama H, Inui T. Alcohothermal treatments of gibbsite: mechanism for the transformation of boehmite. Clays Clay Miner. 1989;37(1):71–80.
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The authors are thankful to Ministry of Steel, New Delhi, for sponsoring the research work undertaken in the present study.
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Beuria, P.C., Biswal, S.K., Mishra, B.K. et al. Kinetics study on removal of LOI by thermal decomposition of hydrated minerals associated in hematite ore. J Therm Anal Calorim 126, 1231–1241 (2016). https://doi.org/10.1007/s10973-016-5690-5
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DOI: https://doi.org/10.1007/s10973-016-5690-5