DISSOLUTION OF SODA-LIME, SILICA, AND HIGH-LEVEL WASTE GLASS BY STATIC AND SINGLE-PASS FLOW-THROUGH TESTS

摘要

Static and single-pass flow-through tests (SPFT) were conducted on soda-lime (float and SK1) glasses, silica glass, and a borosilicate (high-level waste high-chromium) glass at 85 and 50 deg C (static tests) and 90, 85, 60, and 30 deg C (flow-through tests). Tests were performed at pH 10, 6, 5.5, 4 and 2; some static tests were unbuffered. Solution pH in unbuffered static tests on soda-lime glass changed rapidly during the first 24 h, while in SPFT tests, the pH change was not significant. Borosilicate glass dissolved minimally near pH 4 and more rapidly with increasing and decreasing pH. Borosilicate glass dissolved much more incongruently in the initial dissolution stage than soda-lime glasses, but less so with time. The activation energy of the final dissolution rate based on the normalized Si release was 47.4+-4 kJ/mol for SK1 glass, 55.4+-11 kJ/mol for the float glass, and 52.4+-13 kJ/mol for the borosilicate glass.