Tantalum Smelting Methods

Tantalum-niobium ore is often accompanied by a variety of metals, the main steps of tantalum smelting is to decompose the concentrate, purify and separate tantalum and niobium, in order to produce tantalum and niobium pure compounds, and finally to produce the metal.
Ore decomposition can be hydrofluoric acid decomposition method, sodium hydroxide melting method and chlorination method. Tantalum-niobium separation can use solvent extraction method [commonly used extractants are methyl isobutyl ketone (MIBK), tributyl phosphate (TBP), sec-octanol and acetamide, etc.], step-by-step crystallization method and ion exchange method.

Separation: Firstly, the tantalum-niobium iron ore concentrate is decomposed into tantalum and niobium by hydrofluoric acid and sulphuric acid to present fluorotantalum and fluoroniobium acid dissolved in the leaching solution, and at the same time, iron, manganese, titanium, tungsten, silicon and other accompanying elements are also dissolved in the leaching solution, which forms a strongly acidic solution with very complex composition. Tantalum niobium leaching solution with methyl isobutyl ketone extraction of tantalum niobium extracted into the organic phase at the same time, with sulfuric acid solution to wash trace impurities in the organic phase, to get pure organic phase containing tantalum niobium wash and extraction of the residual liquid merger, which contains trace tantalum and niobium and impurities, is a strong acidic solution, can be integrated recovery. Pure organic phase containing tantalum and niobium with dilute sulfuric acid solution back-extraction of niobium to get the organic phase containing tantalum. Niobium and a small amount of tantalum into the aqueous phase and then extract the tantalum with methyl isobutyl ketone to obtain a pure solution containing niobium. The pure tantalum-containing organic phase is back-extracted with water to obtain a pure tantalum-containing solution. The organic phase after the back-extraction of tantalum is returned to the extraction cycle. Pure fluorotantalum acid solution or pure fluoroniobium acid solution reacts with potassium fluoride or potassium chloride to produce potassium fluorotantalate (K2TaF7) and potassium fluoroniobate (K2NbF7) crystals, and also reacts with ammonium hydroxide to produce tantalum hydroxide or niobium hydroxide precipitates. Tantalum or niobium hydroxide is calcined at 900~1000℃ to produce tantalum or niobium oxide.