Technology:
Chemical Extraction
- Process involves application of heated bicarbonate solution to soil in a rotary reactor, liquid/soils separation, dewatering, and ion exchange to remove uranium from liquid
- Solution was 0.2 M NaHCO3 at a 115°F and retention time of 1.5 hrs; reactor was a 5 yd3 cement mixer
- Processed 1 to 2 tons of soil/batch, using a 30% solids slurry
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Cleanup Authority:
NRC
Points of Contact:
Ward Best, DOE Ashtabula Area Office, (216) 993-1944
Jeff Kulpa, RMI Environmental Services, (216) 993-2804
Erik Groenendijk, ART pilot project manager, (813) 264-3529
Mike Hightower
Sandia National Laboratories
Telephone: (505) 844-5499
Fax: (505) 844-0116
E-mail: mmhight@sandia.gov
Brian Nickel
Ohio EPA
401 East Fifth Street
Dayton, OH 45402-2911
Telephone: (513) 285-6357
Fax: (513) 285-6249 |
Contaminants:
Radionuclides - Uranium
- most uranium present as U+6
- uranium levels in feed soil were 74 - 146 pCi/g |
Waste Source:
Particulates from uranium extrusion operations |
Type/Quantity of Media Treated:
Soil
- 64 tons (38 batches)
- high clay content silt loams and clay loams; low organic material |
Purpose/Significance of Application:
Demonstration of chemical leaching process for treatment of uranium-contaminated soil |
Regulatory Requirements/Cleanup Goals:
- Evaluate process performance, such as ability to meet a 30 pCi/g free release standard and achieve a significant volume reduction of the waste |
Results:
- Treated soil from two areas of the plant had 12-14 pCi/g of uranium, with removal efficiencies of 87-91%
- Treated soil from another area of the plant had 27-47 pCi/g; the higher concentrations was attributed to high feed concentrations from a hot spot with 587 pCi/g
- Volume reduction was 95%; less than 5% residual waste required off-site disposal
- Average feed concentration to ion exchange was 16 ppm and output 1.7 ppm, resulting in a 91% removal efficiency |
Cost Factors:
- The total cost for the pilot plant was $638,670, including mobilization and preparatory work; monitoring, sampling, testing, and analysis; chemical treatment; decontamination and decommissioning; disposal commercial); demobilization; and data compilation and report writing
- The report authors indicate that a linear relationship does not exist between pilot plant and full-scale costs
- Full-scale costs were estimated as $250-350 |
Description:
From 1962 to 1988, the RMI Titanium Company (RMI) performed uranium extrusions operations for the U.S. DOE at its plant in Ashtabula, Ohio. The uranium metal processed at the site included deleted and slightly enriched material that was used in nuclear and non-nuclear weapons. During the early years of extrusion and machining, particulate uranium was generated and discharged from roof vents and stacks and settled on surrounding soils. A test of a carbonate extraction process was conducted to leach uranium from contaminated soils.
Thirty-eight batches of 1-2 tons/batch were treated in a pilot-scale test of a chemical extraction process, through DOE's ITRD program. Treated soil had an overall removal efficiency of approximately 82% with a volume reduction of 95%; less than 5% of residual waste required off-site disposal. Difficulties with meeting the cleanup goal were identified only when treating soil from a hot spot. The total cost for the pilot plant was $638,670, and full-scale costs were estimated as $250-350/ton. |
