ISSN:
1573-8205
Source:
Springer Online Journal Archives 1860-2000
Topics:
Energy, Environment Protection, Nuclear Power Engineering
,
Physics
Notes:
Conclusions In the process of vitrification of high-level wastes the platinum-group elements form at the calcination stage phases which have a limited solubility in the glass melts. If the dissolved part of the platinum-group elements, which at 1200–1300°C does not form more than 30% of their total concentration in the melt [3], is neglected, then apparently it can be assumed that the behavior of the dispersed particles of the platinum-group elements is determined by their thermodynamic stability, interaction with one another, and sedimentation, and the melts of the phosphate and borosilicate glasses play the role of an inert medium. Ruthenium dioxide and the solid solutions based on it, which contain up to 1.5% Ru, Rh, and Pd, are stable up to 1500°C. In the temperature range 1050–1200°C rhodium oxide and the solid solutions based on it, decompose and form metallic rhodium. Metallic palladium apparently forms at 800–900°C. In ceramic melters the temperature of the glass melt is equal to the temperature of the dispersed particles and the composition of the heterogeneous phase based on the platinum-group elements will be determined by the temperature chosen for performing the vitrification process. Induction heating results in local overheating of the electrically conducting dispersed particles by the high-frequency field and, irrespective of the process temperature, in the melt it forms alloys based on platinum-group elements. In summary, the local temperature of the dispersed particles will determine their phase composition, their density, and ultimately their rate of sedimentation and accumulation at the bottom of the melters.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02406202
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