Preparation method of tantalum

Smelting method: tantalum and niobium ore is often accompanied by a variety of metals, the main steps of tantalum smelting is the decomposition of concentrate, purification and separation of tantalum and niobium, to get tantalum and niobium pure compounds, and finally to get metal.

Ore decomposition can be hydrofluoric acid decomposition method, sodium hydroxide melting method and chloride method. Tantalum and niobium can be separated by solvent extraction (commonly used extractants are methyl isobutyl ketone (MIBK), butyl phosphate (TBP), sec-octanol and acetamide, etc.), fractional crystallization and ion exchange. Separation: first of all, the tantalum and niobium concentrate is decomposed with hydrofluoric acid and sulfuric acid, tantalum and niobium are fluotantalic acid and fluobium acid are dissolved in the leaching solution, while iron, manganese, titanium, tungsten, silicon and other associated elements are also dissolved in the leaching solution, forming a very complex composition of strong acid solution. The tantalum and niobium leaching solution is extracted from the organic phase with methyl isobutyl ketone, and the trace impurities in the organic phase are washed with sulfuric acid solution. The pure organic phase washing solution containing tantalum and niobium is combined with the residual solution, which contains trace tantalum and niobium and impurity elements. It is a strong acidic solution and can be comprehensively recovered. Organic phase containing tantalum and niobium is obtained by reverse extraction of niobium with dilute sulfuric acid solution. Niobium and a small amount of tantalum enter the aqueous phase and then the tantalum is extracted with methyl isobutylketone to obtain a pure solution containing niobium. Pure organic phase containing tantalum can be obtained by reverse extraction with water. After the reverse extraction of tantalum, the organic phase returns to the extraction cycle. A pure or pure fluotantalic acid solution reacts with potassium fluoride or potassium chloride to form potassium fluotantalate (K₂TaF₇) and potassium fluotantalate (K₂TaF₇) crystals, respectively, and can also react with ammonium hydroxide to form tantalum hydroxide or niobium hydroxide precipitates. Tantalum or niobium hydroxide is calcined at 900~1000℃ to form tantalum or niobium oxide.