Tantalum is a rare metal. The average yearly growth rate of about 8 to 12% in tantalum demand since about 1995 has caused a significant increase in exploration for this element.
Tantalum minerals with over 70 different chemical compositions have been identified. Those of greatest economic importance are tantalite, microlite, and wodginite; however, it is common practice to name any tantalum-containing mineral concentrate as ‘tantalite’ primarily because it will be processed for the tantalum values and is sold on that basis.
The downsizing of the tin industry in Southeast Asia and elsewhere over the period from 1980 through to 1990 has led to the reduction of tantalum oxide units available from tin slags, a by-product of the smelting of cassiterite ore concentrates for tin production. Although some tin slags are available from new tin production, the primary source today is from the digging up of old dump areas containing 1.5 to about 4.0% tantalum oxide. Struverite concentrates have been available from this general area containing 9-12% tantalum oxide. Scrap recycling generated within the various segments of the tantalum industry accounts for about 20 to 25% of the total input each year.
Once mined, tantalum ore must be processed before it can be used by the capacitor industry. Tantalum powder must be engineered to a high purity, with low levels of oxygen, potassium, nitrogen, and other materials. Tantalum wire is extruded from these tantalum powders and used as the connection from the anode in capacitors.
The electronics industry consumes 60% of the world’s tantalum production. The largest application is electronic capacitors, where tantalum’s ability to form stable oxide films creates highly efficient, highly reliable and environmentally versatile components. In semiconductors, with copper replacing aluminium as the material of choice for interconnects, tantalum has emerged as the ideal barrier solution.
Tantalum is also used for ship and aircraft controls, weapon systems, cellular telephones, medical instruments, artificial hips and knees (tantalum is used because the human body doesn’t reject it), and for corrosion resistant applications in the chemical industry. Additionally, tantalum is being used increasingly in superalloys in aerospace applications. As an alloy it is used to create hard tools for cutting and to create specialized glass for optical purposes. More recently, Tantalum chip capacitors are being used in medical technology that improves the control of epileptic seizures.
Canada is the major tantalum producer in North America. Tantalum Mining Corporation (Tanco) owns a major, active mine in Lake Manitoba, a desirable source because of its high concentration of tantalum. Tanco is owned by Cabot Corporation, which opens and closes the mine as the market dictates. In 2001, Cabot increased shipments from the Tanco mine to make up for declining shipments from Africa.
Angus & Ross PLC of the United Kingdom is attempting to develop tantalum sites in counties Carlow and Wexford in Ireland and the Motfeldt Center in Greenland. New prospecting ventures for tantalum ore are underway in Finland. Solid Resources Limited has formed a subsidiary to hold a 60% interest in a tantalum lithium mining venture in Spain.
The People’s Republic of China has many mines in operation, although the majority of them are small. The largest and most productive mine is the Yichun mine, which is a prime source for Ningxia Non-Ferrous Metals, a major engineered-powder processor, and the smaller, Nanjing mine, also located in China, a major processor.
|South America:The major mine in Brazil is the Nazareno mine, which is owned by Metallurg’s CIF subsidiary. This is the third largest mine in the world behind the Greenbushes and Wodgina mines in Australia. A second, smaller mine, is the Mamore site (Pitinga), which is owned by Grupo Paranapanema.||Africa:Africa produces 25% of the world’s tantalum ore. Ore sources abound in Africa and are easily accessible because the ore is located close to the surface. Ore is mined by individuals, collected by assayers, and then sold to a few major African ore traders. Most traders are owned and operated by the governments of the Democratic Republic of Congo, Rwanda, and Uganda. They in turn sell the ore to international distributors such as Umicore (formerly Sogem) and A&M Metals. Ore sales from Africa are also made directly to major player Cabot Corporation.||Australasia:Australia is a major producer, accounting for some 25% of world production. Sons of Gwalia owns and operates the Greenbushes and Wodgina mines that contain significant deposits of tantalite. In 2000, Sons of Gwalia mined and sold about 1.3 million pounds of tantalum ore, which suggests they controlled about 25% of the total tantalum supply and 40% of the primary supply (i.e., excluding ore from stockpiles, recycling, or the U.S. Defense Logistics Agency).|