A Brief History of Tantalum and Niobium Metallurgy

(1) In 1801, British chemist Hartchet discovered the element niobium; In 1802, Swedish chemist Anders Gustav Eckberg discovered the element tantalum.

(2) In 1865, Swiss chemist Malignac invented the step-by-step crystallization method for separating tantalum and niobium.

(3) In 1866, metal niobium was first obtained by reducing niobium pentachloride with hydrogen at high temperatures.

(4) In 1903, malleable metal tantalum was prepared by reducing tantalum fluoride complex salt with sodium.

(5) In 1922, the production of tantalum powder by molten salt electrolysis was successful, bringing tantalum production to industrial scale.

(6) In 1944, the carbon reduction method of niobium was invented, laying the foundation for the industrial production of niobium

Tantalum smelting steps

Tantalum niobium ore is the main raw material for producing tantalum, but it is often accompanied by multiple metals. Therefore, the main steps of tantalum smelting are to decompose the concentrate, purify and separate tantalum and niobium, to produce pure compounds of tantalum and niobium, and finally to produce metals.

The decomposition of ores can be carried out using methods such as hydrofluoric acid decomposition, sodium hydroxide melting, and chlorination. The separation of tantalum and niobium can be carried out using solvent extraction methods (commonly used extractants include methyl isobutyl copper (MIBK), tributyl phosphate (TBP), secondary octanol, and acetamide), fractional crystallization methods, and ion exchange methods.

Preparation of tantalum metal

The preparation of metallic tantalum refers to the process of reducing pure tantalum compounds to metallic tantalum using a reducing agent. The raw materials used for pure tantalum compounds include tantalum pentoxide, tantalum pentachloride, tantalum pentafluoride, and fluoride salts (such as K2TaF7). Reducing agents include active metals such as sodium and magnesium, as well as carbon and hydrogen. The melting point of tantalum is as high as 3669K, so the result of reduction is a powder like or sponge like metal. Further melting or refining is required to obtain dense metals.

The main methods for producing metallic tantalum include sodium thermal reduction to produce tantalum powder, carbothermal reduction to produce tantalum, and molten salt electrolysis to produce tantalum powder. Sodium thermal reduction of potassium fluotantalate is a widely used tantalum production method worldwide. The resulting tantalum powder has a complex particle shape and a large specific surface area, making it suitable for manufacturing capacitors. Carbon thermal reduction of tantalum pentoxide has become a mature industrial method for tantalum production, but due to insufficient product purity, it is not as widely used as the sodium reduction method. The molten salt electrolysis method is divided into two methods based on electrolyte composition: oxygen containing electrolyte electrolysis and non oxygen containing electrolyte electrolysis. The molten salt electrolysis method can generally only produce metallurgical grade tantalum powder. Hydrogen reduction of tantalum pentafluoride is considered a promising tantalum production method, but it has not yet been used in industrial production due to high equipment material and environmental protection requirements.

Most tantalum is directly used in the form of tantalum powder for manufacturing tantalum capacitors in the electronic industry. Therefore, the powder production process of tantalum, such as capacitor grade tantalum powder production, hydrogenation method tantalum powder production, and tantalum powder vacuum heat treatment, also belong to the category of metal tantalum production.