Industrial Tantalum Manufacture

Methods for separating tantalum and niobium are described in refs. [23.3-5] and in Chapter 22 Niobium. 

Tantalum can be manufactured by carbon reduction in the same way as described for niobium first a reaction between Ta O and carbon to form Ta carbide and then, at a higher temperature  

Another industrial method is reduction of KjTaF by sodium. The two reactants are loaded into a steel bomb. After an external heating the exothermic reaction proceeds vigorously. After cooling, the bomb contents are treated with water and methanol to remove excess sodium and salts. 

Tantalum is also manufactured by electrolysis of melts with the percentage composition 60 KCl, 25 KF, 10 K TaF, and 5 Ta Oj. The electrolysis is carried out in iron crucibles, which are also the cathode. This method made the metal commercially available in the USA in 1922. 

World consumption of tantalum was about 2000 tonnes in 2001. Tantalum, like niobium, is used in superalloys based on nickel and cobalt, intended for aircraft engines and other high-temperature applications. Tantalum carbide TaC is, to a limited extent, used as a hard component in cemented carbide. The oxide is used to make special glass with a high refractive index for camera lenses Two tantalum properties have, however, given the metal its special importance in modern industry. 

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Tantalum, because of its negligible corrosion rate, finds use in the pharmaceutical and food manufacturing industries where even the smallest amount of metallic impurity cannot be tolerated in many products. 

The main reason for the tantalum industry s drive toward the sodium reduction process is an increasing demand for tantalum powder by tantalum capacitor manufacturers. The modem tendency of the electronics industry to miniaturize their components calls for the improvement of tantalum powder... 

Anodic oxidation is a very common process in the electrochemical industry, used for example in the manufacture of aluminum and tantalum capacitors. The anodic oxidation of silicon is not of comparable importance, because the electrical properties of anodic oxides are inferior to those of thermal oxides. 

The first commercial use of tantalum was as filaments in incandescent lamps but it was soon displaced by tungsten. Tantalum is used in chemical industry equipment for reaction vessels and heat exchangers in corrosive environments. It is usually the metal of choice for heating elements and shields in high temperature vacuum sintering furnaces. In 1994, over 72% of the tantalum produced in the world went into the manufacturing of over 10 x 109 solid tantalum capacitors for use in the most demanding electronic applications. 

Vanadium has found important application in the manufacture of special steels, and tantalum is being increasingly employed for electrolytic rectifiers. It seems probable that the industrial application of these elements will increase in the future, and that uses will also be found for niobium. 

Niobium-containing tantalum carbide manufactured with the menstruum process is industrially important... 

The ceramics industry, like many others, can establish production facilities in which labor costs are lower. For example, KEMET Corporation based in Greenville, SC, a manufacturer of tantalum electrolytic and multilayer ceramic chip capacitors, is relocating all manufacturing to lower-cost facilities in Mexico and China. 

Major Applications inks, dye lasers, in manufacture of vinyl polymers, textiles determination of iron, calcium, aluminum, -" tantalum, monitoring hardness in industrial water," measuring chlorine dioxide in drinking water, hypoglycemic agents, nuclear fluorochrome Safety/Toxicity Mutagenicity"... 

In 1963, the value added by batteries and capacitors accounted for over 13 % of the value added by the entire electrochemical industry. Table 10 presents a breakdown of these products. Since the operation of these devices is based on electrochemical principles, 100% of their shipments and value added is recorded as part of the electrochemical industry. The 1958 shipments and value added figures were obtained from the 1958 Census of Manufactures. The 1963 data for aluminum and tantalum capacitors are preliminary Department of Commerce estimates, and the 1963 figure for AC-electrolytic capacitors is our estimate. The remaining 1963 data were obtained from the 1963 Census of Manufactures. 

Loose lining. The loose-lined construction is used to make thick tantalum liners and was historically the first approach to a duplex system. The tantalum liner is manufactured separately and inserted into reactor vessels without bonding with the structural base metal. This loose-lined construction is the most economical and most widely used fabrication method throughout the entire industry. Liner thicknesses of 0.5 to 1 mm are satisfactory against corrosion. It is also possible to improve this technique by welding the liners to the base metal (i.e., weld overlay). Although economical, the loose-lined construction has some intrinsic drawbacks ... 

A passive layer on the metal gives tantalum excellent corrosion resistance and makes the metal suitable for use in chemical industry for applications where the chemical attack is very strong. Tantalum is in fact as resistant as platinum to many corrosive agents and has replaced platinum in laboratory ware and weights in analytical balances. In the chemical industry it is used as liners for reactors and for manufacturing corrosion- and heat-resistant equipment. 

Bayer is linked to the electronics industry via its HC Starck subsidiary which is a leading supplier of tantalum powder to the electrolytic capacitor industry. It also supplies the Baytron P transparent conductive polymer which can be used to manufacture organic light-emitting diodes (OLED). 

This alloy is produced ir all forms although it is ger erally used in multifilament cables. The alloys are manufactured in both grade 1 and grade 2 types. Grade 2 material has a higher allowable tantalum content, which has no effect on the superconducting properties. A wet-grade niobium-55% titanium alloy is also available that finds application in the aircraft industry. 

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