Noble Metal and Spinel Deposition on the Floor of the Joule‐Heated Ceramic Melter

Abstract

At the West Valley Demonstration Project (WVDP), the slurry‐fed ceramic melter (SFCM) was in test operation from December 1984 to December 1989 to vitrify simulated nuclear waste slurries. In this study, deposition of insolubles and crystallized species on the SFCM floor during the vitrification process were analyzed. The results indicate that the thickness of the sludge layer on the floor of the SFCM was not more than 6 cm deep and consisted mostly of Fe‐Cr spinels, and RuO 2 dispersed in a glassy borosilicate matrix. Also, crystalline Ce 2 O 3 and undissolved phases consisting primarily of alumina and chromia were present in trace amounts but were inhomogeneously distributed in the glassy matrix on the SFCM floor. Greater than 87% of the RuO 2 fed to the melter was flushed out with normal glass pouring.