Morphology and Formation Mechanism of Residual Chlorine in Titanium Sponge Produced in the Kroll Process

Autor: Kiyoshi Shibata, Masonori Yamaguchi, Hiroyuki Kitayama, Takefumi Irie, Seiyu Takao, Naoki Tokumitsu, Hiroyuki Takahashi
Rok vydání: 1996
Předmět:
Zdroj: Shigen-to-Sozai. 112:251-256
ISSN: 1880-6244
0916-1740
DOI: 10.2473/shigentosozai.112.251
Popis: The Kroll process consists of the reduction process in which TiCl4 is reduced by Mg and the distillation process in which residual Mg and MgCl2 in the titanium sponge are removed by evacuation. It is well known that the higher the feeding rate of TiCl4 in the reduction process, the higher the chlorine content in the titanium sponge after the distillation process.Microscopic study on the residual chlorine in titanium sponge was conducted usingEPMA and EDX. It was found that there were three types ofresidual chlorine: 1) MgCl2 in micro-cavities in the titanium grains, 2) MgCl2 in the closed space between the titanium particles and 3) TiCl2 on the titanium particle surface. Among them, the second type MgCl2 is ascribed the residual chlorine content. Two routes to from such MgCl2 in the Kroll process were discussed. One was trapping of MgCl2 produced by the reduction of TiCl4 and the other one was MgCl2 formation via TiCl2. The correlation between the residual chlorinecontent and the ratio of the TiCl4 feeding rate to amount of Mg in the reduction vessel could be explained by the both hypothetical mechanisms. It was concluded that theamount of Mg in the vessel is one of the key factors for producing low chlorine content titanium sponge.
Databáze: OpenAIRE
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