Obtaining high magnetic susceptibility phases from Hekimhan& / #8211 / Deveci siderite orevia preliminary thermal treatment has been the basic target of the thesis study.Thermal decomposition characteristics of samples, determined bythermogravimetric analysis (TGA), differential thermal analysis (DTA), and
differential scanning calorimetry (DSC), were referenced in advancement of thestudy. Heat treatment experiments, particularly roasting, were carried out byconventional heating and microwave heating. Results showed that roasting of
Hekimhan& / #8211 / Deveci siderite samples could not be achieved by microwave energywhilst conventional heating experiments recorded success. Subsequentlow& / #8211 / intensity magnetic separation of roasted samples gave recovery above 90%,
where low& / #8211 / intensity magnetic separation of run& / #8211 / of& / #8211 / mine sample had failed.
Formation of high magnetic susceptibility phases was verified by magneticsusceptibility balance and x& / #8211 / ray diffraction analysis (XRD), on roasted samples.
Statistical modeling was applied to determine the optimum conditions of roastingin conventional heating system / based on heating temperature, time of heating, particle size as factors.It was concluded that roasting at T= 560 º / C, for t= 45 minutes was adequate toobtain desired results. Particle size was noted to be not much effective on the
process as other factors at the studied size range.
Kinetics (E, n) and reaction mechanism for the thermal decomposition in conventional heating system were evaluated with different solid& / #8211 / state reaction models by interpretation of the model graphs.Three& / #8211 / dimensional diffusion reaction models reported to characterize the thermal decomposition well, with values of activation energy (E), E= 85.53 kJ/mol
(Jander) / E= 85.49 kJ/mol, (Ginstling& / #8211 / Brounshtein).
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12608729/index.pdf |
| Date | 01 September 2007 |
| Creators | Alkac, Dilek |
| Contributors | Atalay, Mustafa Umit |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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