title: Extraction chromatographic separations of tantalum and tungsten from hafnium and complex matrix constituents.
abstract: Tantalum (Ta), hafnium (Hf), and tungsten (W) analyses from complex matrices require high purification of these analytes from each other and major/trace matrix constituents, however, current state-of-the-art Ta/Hf/W separations rely on traditional anion exchange approaches that show relatively similar distribution coefficient (Kd) values for each element. This work reports an assessment of three commercially available extraction chromatographic resins (TEVA, TRU, and UTEVA) for Ta/Hf/W separations. Batch contact studies show differences in Ta/Hf and Ta/W Kd values of up to 106and 104(respectively), representing an improvement of a factor of 100 and 300 in Ta/Hf and Ta/W Kd values (respectively) over AG1×4 resin. Variations in the Kd values as a function of HCl concentration for TRU resin show that this resin is well suited for Ta/Hf/W separations, with Ta/Hf, Ta/W, and W/Hf Kd value improvements of 10, 200, and 30 (respectively) over AG1×4 resin. Analyses of digested soil samples (NIST 2710a) using TRU resin and tandem TEVA-TRU columns demonstrate the ability to achieve extremely high purification (>99%) of Ta and W from each other and Hf, as well as enabling very high purification of Ta and W from the major and trace elemental constituents present in soils using a single chromatographic step.
authors.affiliation: Idaho National Laboratory, PO Box 1625, Idaho Falls, ID, 83415-2805, USA. Electronic address: mathew.snow@inl.gov.
authors.forename: Mathew S
authors.initials: MS
authors.lastname: Snow
authors.affiliation: Idaho National Laboratory, PO Box 1625, Idaho Falls, ID, 83415-2805, USA.
authors.forename: Martha R
authors.initials: MR
authors.lastname: Finck
authors.affiliation: Idaho National Laboratory, PO Box 1625, Idaho Falls, ID, 83415-2805, USA.
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Carney
authors.affiliation: Pacific Northwest National Laboratory, PO Box 999, MSIN J4-80, 902 Battelle Blvd, Richland, WA, 99352, USA.
authors.forename: Samuel S
authors.initials: SS
authors.lastname: Morrison
mesh_terms: D002852:Chromatography, Ion Exchange; D006195:Hafnium / Q000302:isolation & purification*; D007475:Ion Exchange Resins; D012987:Soil / Q000737:chemistry; D013635:Tantalum / Q000302:isolation & purification*; D014414:Tungsten / Q000302:isolation & purification*
chemical_list: D007475:Ion Exchange Resins; D012987:Soil; D013635:Tantalum; D014414:Tungsten; D006195:Hafnium
keywords: Hafnium; TEVA; TRU; Tantalum; Tungsten