Tantalum and
niobium concentrate as raw material, through acid decomposition, extraction, crystallization, precipitation and drying processes. Design of tantalum niobium smelter workshop for production of tantalum niobium compounds. The main raw materials for producing tantalum and niobium compounds are tantalite, niobium and tantalum-rich tin slag. There are other: pyrochlorite (chlorite) is the main raw material for the production of niobium compounds; The brown yttrium niobium ore, black thin gold ore low grade and high radioactivity, has been rarely used.
Tantalum and niobium compounds are generally intermediate products, which are raw materials for producing tantalum and niobium metal powder, strip and carbide. Ta and niobium oxides are also used as materials for filters, piezoelectric ceramics, monolithic capacitors and optical glass.
The main tantalum compounds are potassium fluoride tantalate and tantalum oxide. Niobium compounds include potassium fluoride niobate, niobium oxide, and other products include tantalum and niobium chloride, nitride and boride.
Selection of process flow: the separation of tantalum and niobium generally uses hydrofluoric acid sulphuric acid decomposition of minerals and extraction method.
The grade of tantalum and niobium concentrates and the ratio of tantalum and niobium are different greatly. Tantalum iron concentrates contain (TaNb)2O5 50% ~ 60% and the highest reaches 80%.Niobium iron concentrate (TaNb)2O5 60% ~ 70%;Tantalum-rich niobium tin slag (TaNb)2O5 20% ~ 30%; Pyrochlorite concentrate contains 40% ~ 60% Nb
2O
5.In order to ensure the stable operation of the production process, in addition to burning chlorite, a variety of tantalum and niobium concentrates are used as raw materials, which are often used after blending. After grinding, the mineral is decomposed by hydrofluoric acid. In order to improve the decomposition rate and to better separate tantalum and niobium during extraction, sulfuric acid is added at the same time. Methyl isobutyl ketone (MIBK) is used as the extractant, which has high saturation capacity of tantalum and niobium, high separation coefficient, good and fast phase separation, reliable recycling performance, but it has disadvantages such as high price, high volatility, high solubility in acidic solution and irritating to central nervous system by inhaling its gas. Some tantalum and niobium smelters in China use mixed alkyl acetamide and octanol extractants, which are low in price, low in volatility and acid solubility, but high in viscosity at low temperature, which affects the extraction effect. There are two extraction processes: clear liquid extraction and pulp extraction. The former has high efficiency and convenient operation. The latter has high yield and eliminates the complicated preparation process of clear liquid. The production of high purity oxides adopts segmented extraction process or reextraction by adjusting acid of reverse extraction solution or redecomposition and extraction by hydroxide. Hydrofluoric acid, potassium chloride, potassium fluoride tantalum (niobium) ate crystallized in the stripping solution containing tantalum or niobium, or direct ammonia precipitation to prepare hydroxide. Tantalum (niobium) chloride was produced by chloride method after oxide was mixed with carbon. In general, niobium oxide is produced by hydrofluoric acid decomposition and extraction of pyrochloriite concentrate, and niobium chloride can also be produced by chloride method and then hydrolyzed to obtain niobium oxide.