Mutual effects of metals in extractions from fluoride solutions with oxygen-containing solvents

Abstract The simultaneous extraction of niobium, zirconium and tantalum from hydrofluoric ncid solutions with oxygen-containing solvents has been studied. When solvents of relatively high dielectric constant- tributyl phosphate. methyl isobutyl ketone and cyclohexanone -are used. the extration of micro amounts of niobium and zirconium is suppressed by the presence of macro amounts of tantalum. This suppression of extraction in the presence of tantalum is also evident with solvents of low polarity, such as diethyl and diisopropyl others, but with these solvents, zirconium is co-extracted with niobium. One of the principal causes of these mutual influences of metals is dissociation and association of the compounds extracted in the organic phase. The formation of mixed ion associated in the extract allows co-extraction of one metal with another. Conversely, the dissociation of complex acids in the organic phase causes suppression of extraction of micro elements by the common ion effect.