Factors Affecting the Iron Oxidation State and Foaming in SRP Waste Glass

摘要

Foaming, or the uncontrolled release of gas (primarily O sub 2 ) during melting, has been a problem in vitrification tests with simulated Savannah River Plant waste. The main source of O sub 2 is the reduction of polyvalent cations such as Mn exp 4+ and Fe exp 3+ at high temperatures. The factors that affect the Fe exp 3+ /Fe exp 2+ equilibrium and their relation to foaming were determined. The most important factors are total iron concentration, interactions between iron and other polyvalent cations, and the basicity of the glass. Addition of a reducing agent and the use of a less-reducing glass have prevented foaming problems in recent continuous melter tests. (ERA citation 07:010284)