Solvent-Impregnated Sorbents for Tantalum from Niobium Separation Using a Fixed-Bed Column

Area of Science:

• Materials Science
• Analytical Chemistry
• Nuclear Engineering

Background:

• Reactor-grade niobium steel requires tantalum content below 100 ppm due to tantalum's high neutron capture cross-section.
• High-purity niobium matrices are essential for developing analytical methods, reference solutions, and certified reference materials (CRMs).
• Existing methods for tantalum removal from niobium are insufficient for meeting stringent purity requirements.

Purpose of the Study:

• To develop a novel and efficient method for separating trace amounts of tantalum (Ta(V)) from niobium (Nb(V)).
• To evaluate the efficacy of various sorbents impregnated with methyl isobutyl ketone (MIBK) for tantalum removal.
• To demonstrate the applicability of the developed method for producing high-purity niobium compounds.

Main Methods:

• Extraction chromatography utilizing sorbents impregnated with methyl isobutyl ketone (MIBK).
• Testing of diverse sorbent materials including ion exchange resins, active carbons, carbonized pomace, bentonite, and polyurethane foam.
• Dynamic separation studies using a fixed-bed column packed with MIBK-impregnated active carbon and varying Nb:Ta ratios.

Main Results:

• Active coal-based materials demonstrated the highest tantalum removal efficiency, exceeding 97%.
• Dynamic column studies achieved a tantalum content of 0.027 ppm in niobium solution with an 88.4% niobium yield.
• A high purge factor of 35,000 was obtained for tantalum removal from a 1000:1 Nb:Ta weight ratio solution.

Conclusions:

• The proposed extraction chromatography system using MIBK-impregnated active carbon is highly effective for separating tantalum from niobium.
• This method enables the preparation of pure niobium compounds with extremely low tantalum concentrations.
• The developed technique is suitable for quality control and the production of essential materials for nuclear applications.