The effect of impurities on the calcination behaviour of CaCO3 nuggets
Presence of impurities like SiO2, Al2O3 and MgCO3 affects the calcination behaviour of Limestone in lime kilns. Some research has been carried out to study this effect. The mechanical properties like Shatter and Abrasion index are found to improve slightly with increasing content of impurities. The rate of Calcination gradually reduces with time before attaining saturation, and Interfacial chemical reaction is identified as the rate controlling step. Activation energy is calculated from the slope of the plot: 1-(1-f)0.5 vs time, where f is the extent of Calcination. Depending on the composition of nuggets, the Activation energy varies between 155.389 and 178.112 kJ/mol. The presence of SiO2 and Al2O3 is found to raise the apparent activation energy, E, while the presence of MgCO3 lowers the value of E. The average increase in the apparent activation energy is found to be 2.38 and 1.71 kJ/mol per unit mass % increase in SiO2 and Al2O3 respectively and the average decrease in the apparent activation energy is 1.40 kJ/mol per unit mass % increase in MgCO3.
Ar, I & Dogu, G. 2001. Calcination Kinetics of High Purity Limestone. The Chemical Engineering Journal, 83(2): 131-137
Batenin, V. M., Kovbasyuk, V. I., Kretova, L. G. & Medvedev, Y. V. 2015. Dust reactor for limestone calcination. High Temperature. Pleiades Publishing. 53(2): 289-298
Fall, M., Esquenazi, G., Allan, S. & Shulman, H. & Ceralink Inc. 2011. Rapid limestone calcination using Microwave Assist Technology. 35rd International Conference & Exposition on Advanced Ceramics and Composites. ICACC-S8-023-2011.
Gilchrist, J.D. 1989. Extraction Metallurgy (3rd ed.). Oxford: Pergamon Press. p. 145. ISBN 0-08-036612-0.
Guo, S., Wang, H., Liu, D., Yang, L., Wei, X. & Wu, S. 2015. Understanding the Impacts of Impurities and Water Vapor on Limestone Calcination in a Laboratory-Scale Fluidized Bed. Energy Fuels. 29 (11): 7572-7583
Gupta, S.K., Ramakrishnan, A. & Hung, Y.T. 2007. Advanced Physicochemical Treatment Technologies. Springer-Verlag, Berlin: 611-633
Imhof, A. 2000. Calcination of limestone in a solar reactor. ZKG International. 53: 504-509
James, R. E., & Richards, G. A. 1992. Limestone Calcination during Pulsating Combustion. 1992. Atomic Energy Commission USA -Reports- 285. Coal-fueled heat engines, advanced pressurized fluidized-bed combustion and gas stream clean up systems contractors review meeting
Kilic, O. & Anil, M. 2006. Effects of Limestone characteristic properties and calcination temperature on lime quality. Asian Journal of Chemistry. 18(1): 655-666
Lindquist, W., Prokesch, M. & Smith, D. 1998. Calcination of limestone fines. World Cement. Palladian publications. 29(3): 8-18
Moffat, W. & Walmsley, M.R.W. 2006. Understanding Lime Calcination Kinetics for Energy Cost Reduction. 59th Appita Conference, Auckland, New Zealand, 16-19 May 2006.
Mu’azu, K., Abdullahi, M. & Akusu, A.S. 2011. Kinetic Study of Calcination of Jakura Limestone Using Power Rate Law Model. Nigerian Journal of Basic and Applied Sciences, 19(1): 116-120.
Okonkwo, P.C. & Adelifa, S.S. 2012. The Kinetics of Calcination of High Calcium Limestone. International Journal of Engineering Science and Technology, 4(2): 391-400
Wakefield, A. & Tyner, M. 1950. Low Temperature Calcination Rates of Limestone. Industrial & Engineering Chemistry. American Chemical Society. 42(10): 2117-2121