What happens to tantalum during solvent extraction of niobium ores?

During the solvent extraction of niobium ores, tantalum is separated from niobium through a liquid-liquid extraction process. After the ore or ferroalloy is decomposed in hydrofluoric acid to create an aqueous feed solution, an organic solvent—typically methyl isobutyl ketone—is introduced.1

In this process, the tantalum is extracted as a fluoride into the organic solution, while the niobium remains in the aqueous residue, known as the raffinate. This separation is possible because, despite the two elements' great chemical similarity, their distinct properties allow for isolation through this chemical method. Once extracted, the tantalum can be further processed and reduced to metallic tantalum powder.12