Non-isothermal kinetic study on the dehydration of mechanically activated alunite

Bu çalışmada, alunit cevheri bir atritörde 15 dakika süreyle aktive edilmiş, daha sonra farklı ısıtma hızlarında hem aktive edilmemiş hem de aktive edilmiş alunitin termal analizleri alınmıştır. Termogravimetrik data kullanılarak, alunitin dehidratasyon kinetiği KAS (Kissenger-Akahira-Sunose) denklemiyle incelenmiştir. Alunitin dehidratasyon kinetiği ve termal davranışı üzerine mekanik aktivasyonun etkisi araştırılmıştır.

Mekanik aktive edilmiş alunitin dehidrasyonu üzerine izotermal olmayan kinetik çalışması

In this study, alunite ore was activated mechanically in an attritor for 15 min and then thermal analysis was carried out on both non-activated and activated alunite in different heating rates. Using of thermogravimetry data, the dehydration kinetics of alunite was studying with KAS (Kissenger-Akahira-Sunose) equation. The effect of mechanical activation on the dehydration kinetics of alunite and its thermal behaviour were investigated.

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[1]. Gülensoy, H., The study of Turkish ahmite by thermogravimetric and microcalorimetric methods and determination of solubilities of pyrolsis products in water and sulphuric acid (in Turkish) MTA Enstitüsü Dergisi, 71,93-128,1968
[2]. Gülensoy, H., Şengil, İ.A., 777e occurences and reserves of alunite ore (in Turkish), Kimya ve Sanayii Dergisi, 31(157-158), 116-131, 1989.
[3]. Özacar, M., Şengil, İ.A., Optimum conditions for leaching calcined alunite ore in strong NaOH, Can. Metallurgical Quarterly, 38(4),249-255, 1999
[4]. Küçük, A,, Gülaboğlu, M.Ş., Thermal decomposition of Şaphane alunite ore, Ind.Eng.Chem.Res., 41, 6028- 6032, 2002
[5].Şengil, İ.A., Thermal decomposition of Şaphane alunite-potassium, sodium, barium or calcium chloride mixtures, Turk. J. Eng. Environ. Sci., 15, 436-446, 1991
[6].Balaz, P., Extractive Metallurgy of Activated Minerals, Elsevier Science B.V., Amsterdam, The Netherlands, 2000.
[7].Balaz, P., Boldizarova, E., Achimovicova, M, Kammel, R., Leaching and dissolution of a pentlandite concentrate pretreated by mechanical activation, Hydrometallurgy, 57(1), 85-96, 2000
[8].Küçük, F., Mekanik aktive edilmiş alunitin termal dekompozisyon kinetiğinin termogravimetri ile incelenmesi, Yüksek Lisans Tezi, Fen Bil.Ens., Sakarya Üniversitesi, Aralık 2005.
[9].M.E. Brown, Introduction to Thermal Analysis-Techniques and Applications, 2nd Ed., Kluwer Academic Pub., NJ, USA, 2001 [10]. R.R. Keuleers, J.F. Janssens, H.O. Desseyn, Comparison of some methods for activation energy determination of thermal decomposition reactions by thermogravimetry, Thermochimica Acta, 385, 127-142,2000
[11]. K.Yıldız, Z.Arslanoğlu, H.Ö.Toplan, Thermal decomposition of mechanically activated alunite (in Turkish), 12th Int. Metallurgy-Material Congress and Fair, Istanbul, Turkey, Sept.28-Oct. 2/2005
[12]. L.H. Yue, D.L. Jin, Z.D. Xu, The non-isothermal kinetic analysis of thermal decomposition of Mg(OH)2, Acta Phys. Chim. Sin., 21(7),752-757,2005
[13]. A.Khawam, D.R. Flanagan, Role of isoconversional methods in varying activation energies of solid state kinetics. I-Isothermal kinetic studies, Thermochimica Acta, 429, 93-102, 2005