Kinetics of Reactive Extraction of Nd from Nd2O3 with TBP-HNO3 Complex in Supercritical Carbon Dioxide

Rare earth element extraction from pretreated bastnäsite in supercritical carbon dioxide

“…Supercritical CO 2 with TBP has been used to extract REEs (and actinides) from aqueous nitrate solutions [8][9][10] and from solid nitrate salts [11][12][13]. Another option is to premix TBP and HNO 3 to form a liquid adduct, dissolve this adduct in supercritical CO 2 , and use this modified CO 2 to extract REEs from acid-soluble mineral phases such as oxides [14][15][16][17][18][19]. In the latter configuration, the extraction mechanism involves three sequential steps in a single reaction vessel: reaction of REE minerals with nitric acid to form REE nitrates, complexation of the nitrate salt with TBP, and dissolution of the metal complex in CO 2 .…”

“…A note of caution should be given with regard to mixing, handling, use, and storage of TBP and nitric acid mixtures. Mixtures comprised of concentrated (70%) nitric acid and TBP have previously been characterized and widely reported in literature without mishap [14][15][16][17][18][19]. Care should be taken not to formulate mixtures of TBP and fuming nitric acid which would result in a mixture having greater than approximately 10 M H + in the organic phase because such mixtures have been found to be unstable and can undergo rapid exothermic decomposition (hydrolysis).…”

“…The extraction pressure was set at 34 MPa to dissolve the full range of adduct compositions by a comfortable margin [16] and a reaction column temperature of 65°C because extractions near this temperature had achieved high recoveries in previous studies [14,15].…”

Nitrate conversion and supercritical fluid extraction of UO2-CeO2 solid solution prepared by an electrolytic reduction-coprecipitation method

“…A schematic diagram of the apparatus has been depicted elsewhere [34]. The apparatus consists of a stainless steel extraction vessel with a volume of 50 mL.…”

Ekstraksi Pemisahan Neodimium dari Samarium, Itrium dan Praseodimium Memakai Tri Butil Fosfat

“…Ligan campuran yang mengandung thenoyl trifluoroacetone (TTA) dan tri-butylphosphate (TBP), 35 MPa dan 60° C. TBP-HNO 3 digunakan untuk ekstraksi Nd 2 O 3 dalam SC-CO 2 [12]. Efek suhu dan tekanan mengindikasikan bahwa proses kinetik ekstraksi reaktif dikontrol oleh reaksi kimia.…”