Understanding of uranium extraction mechanisms from phosphoric and sulphuric media using DEHCNPB

Autor: Fries, B., Berger, C., Marie, C., Pacary, V., Sorel, C., Mokhtari, H., Charbonnel, M.-C.
Přispěvatelé: CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), SEPA, AREVA NC, amplexor, amplexor, ORANO, CADARACHE, Bibliothèque
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: ISEC 2017-The 21st International Solvent Extraction Conference
ISEC 2017-The 21st International Solvent Extraction Conference, Nov 2017, Miyazaki, Japan
URAM 2018
URAM 2018, Jun 2018, Vienne, Austria
Popis: International audience; Phosphate rocks are widely exploited for the manufacturing of phosphoric acid and fertilizers but they contain uranium (30-300 ppm). Therefore, recovering this uranium would enable the decontamination of phosphoric acid while valorizing uranium for the nuclear industry. Following a renewal of interest for the recovery of uranium from phosphate ores in the past few years, new extractant molecules were investigated in order to develop a new solvent extraction process. An amidophosphonate, the butyl-1-[N,N-bis-2-ethylhexyl)carbamoyl]nonyl phosphonic acid (DEHCNPB), showed good uranium extraction efficiency while meeting U/Fe decontamination requirements (as demonstrated during pilot scale trials). Afterwards, DEHCNPB was also used for the extraction of uranium from conventional resources (from sulfuric lixiviation media). However, pilot scale trials showed poorer performances, as uranium leaks in raffinates were higher than expected. The objective here is to study uranium and iron extraction mechanisms from those two different media (phosphoric and sulfuric). Thermodynamical data were acquired such as extraction isotherms, slope analysis, phosphates/ sulfates and water extraction. These data showed different behaviors depending on the initial medium. Spectroscopic techniques such as FTIR, NMR, ESI-MS and EXAFS were also investigated to study uranium-DEHCNPB complexes formed in the organic phase, enabling the determination of stoichiometries and coordination modes
Databáze: OpenAIRE