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Mechanism of magnesium oxide chlorination by hydrogen chloride in a molten salt

The reaction of HCl gas with MgO particles suspended in a molten salt containing magnesium chloride was studied. Chlorination experiments were carried out in a batch stirred tank reactor. The determination of the MgCl2 concentration as a function of chlorination time indicated that the chlorination of MgO to MgCl2 occured through an intermediate step. The intermediate species was assumed to be MgOHCl forming according to the reaction: MgOs+HCl g→MgOHCl d / Alkalimetric titration and thermal decomposition by injection of dry nitrogen were used to confirm the existence of MgOHCl in the molten salt during chlorination. Infrared spectrometry was also tentatively used to identify MgOHCl but, without success due to the hygroscopic nature of the material. / Conventional mass transfer theory was used to develop a model for the reaction of solid MgO particles with HCl dissolved in the molten salt to form MgOHCl. The model assumed shrinking particle behaviour for the MgO and was confirmed by the data from the chlorination experiments. / Moreover, experiments conducted at different HCl flow rates showed that the reaction was controlled by mass transfer of HCl dissolved in the molten salt across the liquid film surrounding the MgO particle to the surface of the particle. The following rate law was obtained CMgOCi MgO1/3=1-K nt the constant Kn was found to vary between 0.04 and 0.08 s-1 when the gas flow rate was varied from 2.5 to 7.5 SLPM at constant temperature and agitation speed of 500°C and 500 RPM, respectively.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.33977
Date January 2001
CreatorsLamy, Martin.
ContributorsHarris, Ralph L. (advisor)
PublisherMcGill University
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Formatapplication/pdf
CoverageMaster of Engineering (Department of Mining, Metals and Materials Engineering.)
RightsAll items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated.
Relationalephsysno: 001872490, proquestno: MQ79080, Theses scanned by UMI/ProQuest.

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