Pilot Scale Validation of a Chemical Process for Uranium, Cesium, and Mercury Recovery from Cemented Radioactive Wastes
The medical isotope (Mo-99) production at Chalk River Laboratory involves the dissolution of irradiated isotope targets prior to the extraction of Mo-99. This process generates a waste that is cemented in 5-gallon containers and transferred to a waste-management facility for intermediate storage. Ov...
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MDPI AG
2022-05-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/12/5/594 |
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| author | Nicolas Reynier Maxime Courchesne Javed Anderson Kevin Williams Kyle Schinnour |
| author_facet | Nicolas Reynier Maxime Courchesne Javed Anderson Kevin Williams Kyle Schinnour |
| author_sort | Nicolas Reynier |
| collection | DOAJ |
| description | The medical isotope (Mo-99) production at Chalk River Laboratory involves the dissolution of irradiated isotope targets prior to the extraction of Mo-99. This process generates a waste that is cemented in 5-gallon containers and transferred to a waste-management facility for intermediate storage. Over the past decades, a large number of five-gallon containers of cemented radioactive waste (CRW) were produced, and Canadian Nuclear Laboratories (CNL) must develop a process to convert this material to a permanent waste form. Research has been undertaken to develop an innovative method for the recovery of U, Hg, and Cs from surrogate cemented radioactive waste (SCRW). This paper presents the pilot scale validation of the operating parameters prior to the demonstration scale testing. Leaching tests at the pilot scale were conducted with 5 kg of SCRW to validate the main operating parameters and evaluate the reuse of the leaching solution. The mean solubilization yields obtained at the pilot scale were 81.9 ± 8.3% for Cs, 99.0 ± 1% for U, and 94.9 ± 4.5% for Hg. Columns with 100 g of KNiFC-PAN and 250 g of Lewatit TP214 allow for the separation of Cs and Hg from 60 L of leaching solution without U loss. Flow rates of 12.5 BV/h and 25 BV/h were suitable to achieve 99% separation of Hg and Cs, respectively. For the Hg resin, the capacity reached 23.4 mg/g, and the capacity for the Cs resin reached 0.79 mg/g. The pilot scale U extraction results showed that the U adsorption is selective, with a breakthrough at 36 BV (capacity for U of 3.70 mg/g). Uranium elution with 1 M Na<sub>2</sub>CO<sub>3</sub> exceeded 99%, and subsequent precipitation with NaOH achieved 99% recovery. SEM data confirmed the high purity of the U solids produced as sodium di-uranate. |
| first_indexed | 2024-03-10T03:21:35Z |
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| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-10T03:21:35Z |
| publishDate | 2022-05-01 |
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| series | Minerals |
| spelling | doaj.art-ded10e2d30f941a2a4509c43efa5bf1d2023-11-23T12:19:07ZengMDPI AGMinerals2075-163X2022-05-0112559410.3390/min12050594Pilot Scale Validation of a Chemical Process for Uranium, Cesium, and Mercury Recovery from Cemented Radioactive WastesNicolas Reynier0Maxime Courchesne1Javed Anderson2Kevin Williams3Kyle Schinnour4CanmetMINING, Natural Resources Canada, Ottawa, ON K1A 0E4, CanadaCanmetMINING, Natural Resources Canada, Ottawa, ON K1A 0E4, CanadaCanadian Nuclear Laboratories, Chalk River, ON K0J 1JO, CanadaCanadian Nuclear Laboratories, Chalk River, ON K0J 1JO, CanadaCanadian Nuclear Laboratories, Chalk River, ON K0J 1JO, CanadaThe medical isotope (Mo-99) production at Chalk River Laboratory involves the dissolution of irradiated isotope targets prior to the extraction of Mo-99. This process generates a waste that is cemented in 5-gallon containers and transferred to a waste-management facility for intermediate storage. Over the past decades, a large number of five-gallon containers of cemented radioactive waste (CRW) were produced, and Canadian Nuclear Laboratories (CNL) must develop a process to convert this material to a permanent waste form. Research has been undertaken to develop an innovative method for the recovery of U, Hg, and Cs from surrogate cemented radioactive waste (SCRW). This paper presents the pilot scale validation of the operating parameters prior to the demonstration scale testing. Leaching tests at the pilot scale were conducted with 5 kg of SCRW to validate the main operating parameters and evaluate the reuse of the leaching solution. The mean solubilization yields obtained at the pilot scale were 81.9 ± 8.3% for Cs, 99.0 ± 1% for U, and 94.9 ± 4.5% for Hg. Columns with 100 g of KNiFC-PAN and 250 g of Lewatit TP214 allow for the separation of Cs and Hg from 60 L of leaching solution without U loss. Flow rates of 12.5 BV/h and 25 BV/h were suitable to achieve 99% separation of Hg and Cs, respectively. For the Hg resin, the capacity reached 23.4 mg/g, and the capacity for the Cs resin reached 0.79 mg/g. The pilot scale U extraction results showed that the U adsorption is selective, with a breakthrough at 36 BV (capacity for U of 3.70 mg/g). Uranium elution with 1 M Na<sub>2</sub>CO<sub>3</sub> exceeded 99%, and subsequent precipitation with NaOH achieved 99% recovery. SEM data confirmed the high purity of the U solids produced as sodium di-uranate.https://www.mdpi.com/2075-163X/12/5/594cesiummercuryion exchangeleachingprecipitationradioactive wastes |
| spellingShingle | Nicolas Reynier Maxime Courchesne Javed Anderson Kevin Williams Kyle Schinnour Pilot Scale Validation of a Chemical Process for Uranium, Cesium, and Mercury Recovery from Cemented Radioactive Wastes Minerals cesium mercury ion exchange leaching precipitation radioactive wastes |
| title | Pilot Scale Validation of a Chemical Process for Uranium, Cesium, and Mercury Recovery from Cemented Radioactive Wastes |
| title_full | Pilot Scale Validation of a Chemical Process for Uranium, Cesium, and Mercury Recovery from Cemented Radioactive Wastes |
| title_fullStr | Pilot Scale Validation of a Chemical Process for Uranium, Cesium, and Mercury Recovery from Cemented Radioactive Wastes |
| title_full_unstemmed | Pilot Scale Validation of a Chemical Process for Uranium, Cesium, and Mercury Recovery from Cemented Radioactive Wastes |
| title_short | Pilot Scale Validation of a Chemical Process for Uranium, Cesium, and Mercury Recovery from Cemented Radioactive Wastes |
| title_sort | pilot scale validation of a chemical process for uranium cesium and mercury recovery from cemented radioactive wastes |
| topic | cesium mercury ion exchange leaching precipitation radioactive wastes |
| url | https://www.mdpi.com/2075-163X/12/5/594 |
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