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MAGNESIUM, TITANIUM, RARE METALS, SEMICONDUCTORS
ArticleName Metallothermic reduction of zirconium from oxides
ArticleAuthor Agafonov S. N., Krasikov S. A., Vedmid L. B., Zhidovinova S. V., Ponomarenko A. A.
ArticleAuthorData

Institute of Metallurgy of Ural Branch of Russian Academy of Sciences, Ekaterinburg, Russia:

S. N. Agafonov, Post-Graduate Student, e-mail: agafonovs@yandex.ru
S. A. Krasikov, Leading Researcher
L. B. Vedmid, Senior Researcher
S. V. Zhidovinova, Senior Researcher
A. A. Ponomarenko, Junior Researcher

Abstract

Research of alumino-calciumthermal reduction of zirconium dioxide with obtaining of Al – Zr alloys, containing 50–60% of Zr, was carried out. Usage of methods of differential-thermal analysis (DTA) and X-ray diffraction analysis allowed to reveal that heating of charge materials of ZrO2:Al and ZrO2: (Al+Ca) with relationship of the components from 1.0:0.5 to 1.0:1.0 accompanied with transition to the kinetically active stage of interaction reaction after formation of liquid aluminum. The initial stage at alumino-thermal and alumino-calciumtermal reduction of ZrO2 is characterized by formation of stable congruent Al3Zr compound. Partial (15%) aluminum replacement by calcium in charge material promotes to decrease formation temperature of intermetallic compound from 1022 to 908 оС and to grow the size of exothermic effect corresponding to this process. Modeling of alumino-calciumtermal reduction of zirconium in the resistance furnace was coordinated with DTA data and characterized by good separation of metal and slag phases. Al3Zr and Al2Zr intermetallic compounds were recorded in obtained Zr – Al alloys, containing 50–55% of zirconium. Use of calcium as a reducing agent was accompanied by formation of Al4Ca compound in a metal phase. Application of controlled thermal conditions allowed to carry out the melting process on fusible final slags CaO – Al2O3 – CaF2 and to achieve formation of alloys with oxygen concentration less than 0.15% and nitrogen concentration less than 0.01%, as well as extraction of more than 90% of zirconium into the metal. These observations testify the prospects of usage of such approach in the technology of metallothermal production of aluminum-zirconium alloys.

keywords Aluminothermal reduction, differential thermal analysis, diffractogram, fusion, aluminum-zirconium alloy, intermetallic compounds, extraction, slag
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