Several centuries ago, the province of Saxony was a center for the extraction of non-ferrous metals, including nickel and silver. They were mined in the form of ore, from which the desired substances were then obtained. But sometimes miners found ore that, by all appearances, was supposed to contain silver, but during firing, it was impossible to extract the precious metal from it. Instead, when heated, a poisonous gas was formed that poisoned workers. Saxon miners considered this to be the machinations of an insidious mountain spirit — the kobold, after whom the “bad” ore was named.
It was only in 1735 that the Swedish chemist Georg Brandt managed to obtain pure metal. From the “bad” ore, he isolated a new gray substance with a faint pink tint. In his dissertation dedicated to his discovery, the scientist wrote that the metal found can be used to make safra, a paint that gives glass a rich blue color.
Among the main characteristics of cobalt are its high melting point (1,768°C) and boiling point (3,143°C), density (8.9 g/cm³) and resistance to demagnetization. Under normal conditions, Co does not react with air, alkaline solutions and carboxylic acids. When heated above 300°C, it is covered with a thin oxide film.
In the earth's crust, cobalt is found exclusively in the form of ore or mineral. According to geologists, its amount is approximately 0.004%, which makes Co a rare earth metal.
More than half of the world's cobalt supply (about 6 million tons) comes from one of the West African countries, the Democratic Republic of the Congo. There are also Co deposits in other countries, but they contain this rare earth metal in much smaller quantities:
In all countries, cobalt-containing ore is mined using the quarry method. In production, ore is purified using sulfuric acid or ammonia solution, and refining and electrolysis technologies are also used, which makes it possible to obtain a cleaner product.
Cobalt is mainly produced in the form of a powder that is used as additives to various steels. It increases wear resistance, hardness and heat resistance alloys, which makes it possible to use such compounds for the manufacture of parts that operate under heavy loads, including when creating spacecraft.
Another area of application of Co is the manufacture of motor cores, transformers and other electrical products. In this area, they are valued magnetic properties of cobalt: rare earth metal has a high resistance to demagnetization even under conditions of constant vibrations and high temperatures.
At the beginning of the 21st century, industrial needs required only 2.5-3 thousand tons of Co per year, but by 2010 this figure was 25 thousand tons per year. This is due to the development of microprocessor technology, or rather, to batteries for it. Lithium-cobalt oxide is used to manufacture the battery, which is part of the positive electrodes of lithium-ion batteries: smartphones and tablets contain up to 30 g of cobalt, and electric vehicle batteries contain about 9 kg.
Scientists estimate that demand for cobalt will grow by about 9-10% annually, which, without the development of new deposits, will lead to industrial demand for Co exceeding its production by 2025.