The cobalt

The cobalt is a silvery-white, slightly yellow metal with an atomic number of 27. Mass fraction of it in the earth's crust is 4*10-3%. It is a member of minerals: carolite CuCo2S4, linneite Co3S4, cobaltite CoAsS and other. There are about 30 cobalt-minerals.

The cobalt is a silvery-white, slightly yellow metal with an atomic number of 27

In 1735, the swedish mineralogist Georg Brandt was able to be isolated from the cobalt minerals previously unknown metal, which called the cobalt. He also found that the compounds of this particular element stained a glass in blue this property is used in ancient Assyria and Babylon.

The cobalt is obtained mainly from nickel ores, treating them with solutions of sulfuric acid or ammonia.

The cobalt compounds known to man since ancient times. Cobalt blue glass, enamel, paint found in the tombs of ancient Egypt. So in the tomb of Tutankhamun have found many fragments of the glass.

In the air, the cobalt is oxidized at temperatures above 3000C. Stable at room temperature cobalt oxide is a complex oxide of Co3O4, which has a spinel structure, the crystal structure is one of the sites occupied by ions of Co2+, and the other ions Co3+.

With gray the cobalt forms two different modifications CoS: silver-gray alpha form (with alloying powder), and black beta form (precipitated from solution). The cobalt can dissolve hydrogen without forming chemical compounds. Indirectly synthesized two stoichiometric hydride cobalt: 2 and .

Doping the cobalt to steel increases its heat resistance, improves the mechanical properties of the alloys that create a machining tool: drill bits, cutters, etc...

The cobalt is used as a catalyst for chemical reactions. The lithium cobaltate is used as a highly efficient positive electrode for the production of of lithium batteries.

The cobalt is one of the most relevant trace elements. But when it is ingested in an amount more than necessary, the poisoning can occur. Excess Co alters the hair coloring. They acquire a blue or blue tint. There was a time when the cobalt salt is added to the beer so that it does not spoil and not foamed. And over time, it turned out that the lovers of this drink more often complained of heart failure. Careful studies have shown that the cause of the disease was the cobalt.

Tools