Premium
Effect of Alumina Source on the Rate of Melting Demonstrated with Nuclear Waste Glass Batch
Author(s) -
Pierce David A.,
Hrma Pavel,
Marcial José,
Riley Brian J.,
Schweiger Michael J.
Publication year - 2012
Publication title -
international journal of applied glass science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.383
H-Index - 34
eISSN - 2041-1294
pISSN - 2041-1286
DOI - 10.1111/j.2041-1294.2012.00079.x
Subject(s) - gibbsite , boehmite , corundum , materials science , dissolution , chemical engineering , borosilicate glass , melting point , viscosity , metallurgy , mineralogy , composite material , aluminium , chemistry , engineering
The selection of raw materials affects the rate of batch‐to‐glass conversion. In all‐electric melters, foam under the batch blanket limits the heat flux from the molten glass, thus slowing the rate of melting. Our study, in which we compare the melting behaviors of three batches formulated to vitrify high‐alumina high‐level waste, shows that a slowly dissolving refractory component can cause excessive foaming. Faster melting batches with gibbsite [ Al(OH) 3 ] or boehmite [ AlO(OH) ] as an alumina source produced substantially less foaming than a batch with corundum ( Al 2 O 3 ). Although gibbsite and boehmite dissolved below 500°C, corundum was still present in the batch up to 900°C; hence, the glass‐forming melt lacked alumina in the batch with corundum. The low viscosity of that batch caused the open pores to close prematurely at 660°C, trapping gases and expanding to foam. This would explain the literature‐reported slow melting rate of a batch with corundum, as compared to batches with gibbsite and boehmite.