Tantalum forms a stable anodic oxidation film in acidic electrolyte. Electrolytic capacitors made of tantalum have the advantages of large capacity, small volume and good reliability. The production of capacitors is the most important application of tantalum, and the amount used in the late 1970s accounted for more than 2/3 of the total amount of tantalum. Tantalum is also used to make electronic transmitters and high-power electronic tubes. Tantalum corrosion resistant equipment is used in the production of strong acid, bromine, ammonia and other chemical industries. Tantalum can be used as structural material in the combustion chamber of aircraft engines. The tantalum tungsten, tantalum tungsten and tantalum hafnium alloys are used as heat resistant and high strength materials for rockets, missiles and jet engines, as well as parts for control and regulation equipment, etc. Tantalum is easily machined and used in high temperature vacuum furnaces as supporting accessories, thermal shielding, heaters and heat sinks. Tantalum can be used as orthopedic and surgical materials. Tantalum carbide is used in the manufacture of cemented carbide. Borides, silicides and nitrides of tantalum and their alloys are used as heat release elements and liquid metal cladding materials in the atomic energy industry. Tantalum oxide is used in the manufacture of advanced optical glass and catalysts. In 1981, the percentage of tantalum consumption in the United States was approximately 73% for electronic components, 19% for machinery, 6% for transportation, and 2% for other sectors.
Tantalum and niobium ore is often accompanied by a variety of metals. The main steps of tantalum smelting are to decompose concentrate, purify and separate tantalum and niobium to produce pure compounds of tantalum and niobium, and finally to produce metals. Hydrofluoric acid decomposition method, sodium hydroxide melting method and chlorination method can be used to decompose ore. Tantalum and niobium can be separated by solvent extraction (commonly used extraction agents are methyl isobutyl copper (MIBK), tributyl phosphate (TBP), sec-octanol and acetamide), fractional crystallization and ion exchange method.
First, tantalum and niobium are decompose by hydrofluoric acid and sulfuric acid in the concentrate of tantalum and niobium ore. The tantalum and niobium are dissolved in the leaching solution, and the associated elements such as iron, manganese, titanium, tungsten and silicon are also dissolved in the leaching solution to form a strong acidic solution with very complex composition.
