Alternative and Enhanced Chemical Cleaning: Basic Studies Results Fy2010

Treatment Tank Corrosion Studies for the Enhanced Chemical Cleaning Process

“…Recent tests with PUREX simulant dissolved in 1 wt.% oxalic acid with 0.05 M sulfate showed that the stability of the ferrous oxalate film could be compromised in this manner. Pitting corrosion was observed at temperatures of 45 and 75 °C [33]. From these tables it is apparent that the chloride and sulfate concentrations were higher in the PUREX solution than in the HM solution.…”

Alternative and Enhanced Chemical Cleaning: Corrosion Studies Results: Fy2010

“…This result suggests that boehmite had not dissolved in the solution. Indeed, other tests have shown that boehmite dissolution is ineffective at temperatures less than 70 °C [16]. All corrosion rates were unacceptably high (>150 mpy) and therefore, the nitric acid reagent at the low temperature and high concentration condition should not be utilized for chemical cleaning.…”

“…The size distributions after sonication may be more representative of the solid phase after agitation during batch contact testing. XRD results also indicated a high degree of purity for all crystalline phases [16]. To prepare the mixture for the corrosion tests, 5 g of a solid oxide (e.g., magnetite) was added to 250 ml of reagent (liquid:solid mass ratio: ~50:1).…”

Testing of Enhanced Chemical Cleaning of SRS Actual Waste Tank 5f and Tank 12h Sludges

“…In addition, dissolution times for Tests 1 and 2 ranged from 8-11 hours (Table 3 -5) and previous testing indicated that this timescale is insufficient to reach equilibrium for hematite dissolution in OA. 16 Successively lower iron concentrations were observed for each Test 2 batch, despite the fact that 25% of the iron remained at the conclusion of Batch 3. The soluble iron concentration for Batch 3 was nearly 70% lower than that observed for Batch 1.…”

“…In previous testing with pure hematite (Fe 2 O 3 ), the iron solubility in 1 wt% OA was approximately 0.06 M at 50 °C (pH 1.5, 6 week contact). 16 In 2 wt% OA, the iron concentration would be expected to approach 0.12 M under these same conditions, however, other metals in sludge compete for the added oxalate anion, resulting in a lower iron solubility. In addition, dissolution times for Tests 1 and 2 ranged from 8-11 hours (Table 3 -5) and previous testing indicated that this timescale is insufficient to reach equilibrium for hematite dissolution in OA.…”