A hydrometallurgical method for separating tantalum and niobium from raw materials containing tantalum and niobium by treating them with pure hydrofluoric acid or a mixture of hydrofluoric acid and sulfuric acid, followed by extracting the tantalum and niobium complexes in the treated solution with a methyl isobutyl ketone solvent and steam distilling the organic ketone phase containing tantalum and niobium.
Tantalum and niobium are produced together in most natural sources. However, the different proportions of the two elements indicate the characteristics of the ores and their geological deposition. Niobium is mainly obtained from niobite and/or calcined ore in Brazil, Canada and other regions. However, these ores contain only small amounts of tantalum. Tantalum - rich ores such as tantalite contain correspondingly only a small amount of niobium.
However, to separate tantalum and niobium, slag is also used mainly in the process of separating tin (Thailand, Brazil). Although the tin slag contains only small amounts of niobium and tantalum, they are now considered to be the most important source of these two elements. The Ta/Nb ratio in these tin slags is also very different.
Normally, the two metals and their compounds are separated indirectly from raw materials containing very small amounts of tantalum and niobium, such as tin slag, by means of molten metallurgical enrichment. Only the synthetic tantalum/niobium concentrate obtained by this method can be used for economical wet chemical processing. In these tin slags are also found those which, like natural niobium, contain very little Ta/Nb ratio of tantalum, i.e. they contain a small amount of tantalum but are rich in niobium. For economic reasons, the usual hydrometallurgical treatment and separation processes cannot be applied to these slag as these processes require that the Ta/Nb ratio in the concentrate used be at least 1:3.
The traditional hydrometallurgical method for the separation of tantalum or niobium as disclosed in us patent 3,117,833 is included in the inorganic acid, which is better to treat the tantalum/niobium raw material in the hydrofluoric acid/sulfuric acid mixture. Tantalum/niobium was thus dissolved together in the form of a fluorine complex, followed by a multi-step solvent extraction with MIBK(methyl isobutyl ketone, 2-methyl-pentanone -4) separating first from the associated elements and then from each other. Here, fluorobiobate or fluorotantalate are selectively extracted and further processed to produce pure tantalum or niobium compounds.
