Evaluation of a Phosphinate Functionalized Ionic Liquid for the Separation of Nb and Ta from Nitric Acid Feed Conditions.

48 − 50 This trend has been attributed to the formation of a cation exchange mechanism involving cationic metal–ligand complexed species. The separation factor of Nb over Ta showed an interesting trend: it was also found to decrease with an increase in the nitric acid concentration in the aqueous phase, followed by a peak at 2 M HNO 3 with the β Nb/Ta ∼32 followed by a sudden reduction ( Figure 3 c).

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