Item – Theses Canada

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OCLC number
30665200
Author
Tisdale, David Gordon,1965-
Title
The vapour phase production of titanium.
Degree
Ph. D. -- University of Toronto, 1993
Publisher
Ottawa : National Library of Canada = Bibliothèque nationale du Canada, 1993.
Description
2 microfiches.
Notes
University Microfilms order no. UMI00428152.
Includes bibliographical references.
Abstract
The feasibility of a new process for the production of titanium metal was assessed. The chemistry of the commercial Kroll process (magnesium reduction of titanium tetrachloride) was employed. However, unlike the molten phase reaction of the Kroll process, the reactants were combined in the vapour phase: TiCl$\sb4$(g) + 2 Mg(g) $\to$ Ti(s) + 2 MgCl$\sb2$(g). Argon served as an inert carrier gas to transport reactants to the reaction zone, and to sweep product gases from the zone. This made it possible to operate at 1150$\sp\circ$C to 1250$\sp\circ$C with titanium the only condensed phase present, and presented an opportunity to collect the solid titanium product independently of the other reaction products. Conversion of TiCl$\sb4$ to metallic titanium increased with temperature, residence time and magnesium concentration. The chemical reaction rate was found to be directly proportional to magnesium concentration. An obtained specific reduction rate of 1.9 mol TiCl$\sb4$/m$\sp3$/s was approximately four to five times the productivity reported for a conventional Kroll reactor. Experimental findings agreed with thermodynamic data for TiCl$\sb3$ in the literature. This data had previously been estimated, but not confirmed experimentally, for temperatures above 1050$\sp\circ$C. Titanium powder and titanium plating were two desirable products which formed simultaneously in the experimental system. Plating would likely be the preferred deposit in an industrial application of this process. This type of deposit was favoured by higher reaction temperatures, greater magnesium concentrations, longer residence times, and the presence of a filter in the reaction zone. Plated fractions as high as 98% were obtained. A second application of the experimental system was explored by replacing a portion of the argon carrier gas with nitrogen. This produced titanium nitride, a material employed as a surface coating in high wear applications. Nitride production is of commercial interest, and the process described in this work appears to be a promising alternative to current industrial methods.
ISBN
0315827483
9780315827486