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Title: Extraction of rare earth oxides using supercritical carbon dioxide modified with Tri-n-butyl phosphate–nitric acid adducts

A new tri-n-butylphosphate–nitric acid (TBP–HNO3) adduct was prepared by combining TBP and fuming (90%) HNO3. The adduct was characterized, and its phase-equilibrium behavior in supercritical carbon dioxide is reported. Supercritical carbon dioxide (sc-CO2) was modified with this new adduct [TBP(HNO3)5.2(H2O)1.7], and the extraction efficacies of selected rare earth oxides (Y, Ce, Eu, Tb, and Dy) at 338 K and 34.5 MPa were compared with those obtained using an adduct formed from concentrated (70%) HNO3 and TBP [TBP(HNO3)1.7(H2O)0.6]. All rare earth oxides tested with both adduct species could be extracted with the exception of cerium oxide. Furthermore, the water and acid concentrations in the different adducts were found to play a significant role in rare earth oxide extraction efficiency.
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7]
  1. Idaho National Lab. (INL), Idaho Falls, ID (United States)
  2. Idaho National Lab. (INL), Idaho Falls, ID (United States); Univ. of Idaho, Moscow, ID (United States)
  3. Cornell Univ., Ithaca, NY (United States)
  4. Boise State Univ., ID (United States)
  5. Montana State Univ., Bozeman, MT (United States)
  6. Idaho State Univ., Pocatello, ID (United States)
  7. Univ. of Idaho, Moscow, ID (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0888-5885; PII: S0029549315005956
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Industrial and Engineering Chemistry Research
Additional Journal Information:
Journal Name: Industrial and Engineering Chemistry Research; Journal ID: ISSN 0888-5885
American Chemical Society (ACS)
Research Org:
Idaho National Laboratory, Idaho Falls, ID (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY lanthanide oxides; supercritical carbon dioxide; phase equilibria; acid adduct; extraction