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http://dx.doi.org/10.7844/kirr.2012.21.1.066

Study on Thermodynamic Properties of Sulfidization for Uranium and Rare Earth Oxides  

Lee, Jung-Won (Recycling Process Research Division, Korea Atomic Energy Research Institute)
Lee, Jae-Won (Recycling Process Research Division, Korea Atomic Energy Research Institute)
Kang, Kweon-Ho (Recycling Process Research Division, Korea Atomic Energy Research Institute)
Park, Geun-Il (Recycling Process Research Division, Korea Atomic Energy Research Institute)
Publication Information
Resources Recycling / v.21, no.1, 2012 , pp. 66-74 More about this Journal
Abstract
In order to evaluate the feasibility of selective sulfidization of uranium and rare-earth(RE) oxides, an analysis on thermodynamic data, such as $M-O_2-S_2$ phase stability diagram and changes of Gibbs free energy for sulfidization of uranium and rare-earth oxides were carried out. Comparing $RE-O_2-S_2$ with $U-O_2-S_2$ phase stability diagram at wide range of sulfur potential, $UO_2$ remains unreacted, while RE oxides are sulfidized. The Gibbs free energy change(${\Delta}G^{\circ}$) of sulfidization of RE oxides is lower than that of uranium oxides. Thus, the selective formation of RE sulfides is possible during sulfidization of RE and uranium oxides at lower temperature. $CS_2$ was selected as a sulfidizing agent, because it is a stronger sulfidizing agent than other agents and reacts at lower temperature.
Keywords
Uranium; Rare-earth; Oxides; Sulfides; Sulfidization;
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