Dissolution of two NWCF calcines: Extent of dissolution and characterization of undissolved solids

Brewer, K.N.; Herbst, Ronald; Tranter, T. J.

doi:10.2172/152645

Cited by 6 publications

(5 citation statements)

References 2 publications

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“…There are seven binsets constructed at INTEC with six presently storing calcine. The volume of calcine stored is currently estimated at roughly 4200 m 3 .…”

Section: Experimental Results Of Nwcf Run H-4 Calcine Dissolution Studies Performed In Fy-98 and -99 Background And Introductionmentioning

confidence: 99%

Experimental Results of NWCF Run H4 Calcine Dissolution Studies Performed in FY-98 and -99

Garn¹,

Herbst²,

Batcheller³

et al. 2001

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Dissolution experiments were performed on actual samples of NWCF Run H-4 radioactive calcine in fiscal years 1998 and 1999. Run H-4 is an aluminum/sodium blend calcine. Typical dissolution data indicates that between 90-95 wt% of H-4 calcine can be dissolved using 1gram of calcine per 10 mLs of 5-8M nitric acid at boiling temperature. Two liquid raffinate solutions composed of a WM-188/aluminum nitrate blend and a WM-185/aluminum nitrate blend were converted into calcine at the NWCF. Calcine made from each blend was collected and transferred to RAL for dissolution studies. The WM-188/aluminum nitrate blend calcine was dissolved with resultant solutions used as feed material for separation treatment experimentation. The WM-185/aluminum nitrate blend calcine dissolution testing was performed to determine compositional analyses of the dissolved solution and generate UDS for solid/liquid separation experiments. Analytical fusion techniques were then used to determine compositions of the solid calcine and UDS from dissolution. The results from each of these analyses were used to calculate elemental material balances around the dissolution process, validating the experimental data. This report contains all experimental data from dissolution experiments performed using both calcine blends. ACKNOWLEDGMENTSThe authors wish to acknowledge the RAL analysts who put so much time and effort into the preparation and performance of the dissolution experiments. Those analysts include Alan Olaveson who performed all of the dissolution remote manipulator work, and Blaine Techmeyer, Richard Wells, and Neldon Jackson who provided analytical results from RAL.

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“…There are seven binsets constructed at INTEC with six presently storing calcine. The volume of calcine stored is currently estimated at roughly 4200 m 3 .…”

Section: Experimental Results Of Nwcf Run H-4 Calcine Dissolution Studies Performed In Fy-98 and -99 Background And Introductionmentioning

confidence: 99%

Experimental Results of NWCF Run H4 Calcine Dissolution Studies Performed in FY-98 and -99

Garn¹,

Herbst²,

Batcheller³

et al. 2001

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“…Since the NWCF calcines are intensely radioactive, characterizing them by direct chemical analysis is very difficult (if not impossible). A. L. Olson has developed an Excel spread sheet which predicts calcine composition [4]. Blend compositions, which include actual waste composition, as wells as boric acid and calcium nitrate additions, were entered into this spread sheet so that compositions of both calcine types could be obtained.…”

Section: Sequential Dissolutions With Actual Calcinementioning

confidence: 99%

Experimental results of calcine dissolution studies performed during FY-94,95

Brewer¹,

Olson²,

Roesener³

et al. 1997

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Calcine dissolution studies were performed in FY-94,95 in order to extend the knowledge of dissolution and to obtain information necessary for scale-up design and operation. Experiments reported in this document were performed with non-radioactive and actual calcines to generate qualitative data regarding: a) calcine dissolution rates, b) undissolved solids settling characteristics, c) undissolved solids heel formation, and d) chemical treatments for undissolved solids heel dissolution.The goal of this work was to achieve complete calcine dissolution, or to determine conditions that would result in the maximum calcine dissolution. Small scale laboratory experiments (test-tube dissolutions) and a bench scale dissolver set-up were used in the effort.Results from this work show the bulk of the undissolved solids to settle at a rate of > 9 inches per second when the baseline dissolution parameters are used. Baseline dissolution parameters were 100 grams of calcine being dissolved in 1 L of 5 M HN03 at > 90" C while the solution is being vigorously and constantly mixed. This work also verified that dissolution is most complete when performed with aggressive mixing. Sequential dissolutions performed with non-radioactive and actual calcine indicate that little undissolved solids heel build-up is expected, and this small heel can be further dissolved by increasing the dissolution time or by adding fresh nitric acid.... 111 ACKNOWLEDGMENTS

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“…Dissolution experiments were performed in FY94 and FY95 with two types of actual calcines produced in the New Waste Calcination Facility (NWCF) during campaign H-3 [6,7]. One of the calcines was an Alumina type, albeit non-representative of the early material produced in WCF since the Al liquid waste was very dilute.…”

Section: Introductionmentioning

confidence: 99%

Dissolution Studies With Pilot Plant and Actual INTEC Calcines

Herbst¹,

Garn²

1999

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The dissolution of INTEC (previously the Idaho Chemical Processing Plant) pilot plant calcines was examined to determine solubility of calcine matrix components in acidic media. Two representative pilot plant calcine types were studied: Run 74 Zirconia calcine and Run 64 Zirconia/Sodium calcine. Dissolution of the calcines were evaluated using lower initial concentrations of nitric acid than used in previous tests to decrease the [H + ] concentration in the final solutions. Lower [H + ] concentrations contribute to more favorable TRUEX/SREX solvent extraction flowsheet performance. Experimental results indicated the following conditions define the baseline dissolution process for Zr calcine types:Under the above conditions, the final dissolved solutions contained an H + concentration of ~1.2 M while dissolving >95 wt. % of initial calcine mass. The solution stability adequately met previous calcine dissolution criteria.Dissolution and analytical results were also obtained for radioactive calcines produced in 1998 during NWCF campaign H-4. This calcine was produced using high sodium feeds from tanks WM-185 and WM-188 blended with non-radioactive Al(NO 3 ) 3 solutions to dilute the sodium concentration and prevent bed agglomeration during the calcination process. Due to the addition of Al(NO 3 ) 3 , the H-4 calcines composition resemble that of Al types. Dissolution tests indicated >95 wt. % of the initial calcine mass can be dissolved using the above baseline dissolution procedure, with the exception that higher (5.1 to 5.9 M HNO 3 ) initial nitric acid concentrations are required. The higher initial acid concentration is required for stoichiometric dissolution of the oxides, primarily aluminum oxide, Al 2 O 3 .Statistically designed experiments using Run 74 pilot plant calcine were performed to determine the effect of mixing rate on dissolution efficiency. Three variables were ranked using an interaction analysis to determine the effects of three process variables on the measured response (wt. % dissolution.) The variables were ranked in order of decreasing effect:Temperature > Acid/Calcine Ratio > Mixing Rate Mixing rate was determined to provide minimal effects on wt. % dissolution. The acid/calcine ratio and temperature were the predominate variables affecting the wt. % dissolution, a result consistent with previous studies using other similar types of pilot plant calcines.iv ACKNOWLEDGEMENTS

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Dissolution of two NWCF calcines: Extent of dissolution and characterization of undissolved solids

Cited by 6 publications

References 2 publications

Experimental Results of NWCF Run H4 Calcine Dissolution Studies Performed in FY-98 and -99

Experimental Results of NWCF Run H4 Calcine Dissolution Studies Performed in FY-98 and -99

Experimental results of calcine dissolution studies performed during FY-94,95

Dissolution Studies With Pilot Plant and Actual INTEC Calcines

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