The sources and uses of cobalt

Cobalt’s discovery was in 1735, Swedish chemist obtained when calcining. Cobalt metal is silvery white, the density is 8.9g/cm3, the melting point is 1495℃, the boiling point is 2870℃, valence is +2 and +3, the ionization energy is 7.86 eV. With hard property, malleable, its hardness and oxidation resistance were stronger than iron, but magnetic properties were poor, congruent melting with nickel, aluminum, etc. can be obtained good magnetic steel. It can not react with water and air, but it can quickly be restored by gas erosion, and slowly eroded by hydrofluoric acid, the same with all the transition elements exhibiting price change, and generate colored compounds. It can be used to manufacture heat-resistant super alloys. Cobalt alloys at high temperatures can still maintain its original strength and other valuable properties.

Smaltite and cobaltite is the primary cobalt mine in the nature. Burning the smaltite and cobaltite into oxide and then reduced by aluminum to prepare cobalt. Cobalt-60 is usually prepared by bombarded cobalt metal. For centuries, the blue cobalt salts have been carried exquisite colors. Cobalt alloy can be used to manufacture a device operating at a high temperature. Its radioisotopes can be used to treat diseases. 60Co is a compound can replace radium and to check the internal structure of object, the cracks exist within objects and foreign bodies.

Nanometer cobalt powder can be used in the production of high-density magnetic recording materials, use nano-cobalt powder have high recording density, high coercivity (up to 119.4KA/m), high signal to noise ratio and good oxidation resistance, etc., can greatly improve the tape and high-capacity soft and hard disk performance. Use iron, cobalt, nickel and its alloy powder producing magnetic fluid with good performance, can be widely used in sealing shock absorption, medical equipment, sound adjustment, light display and so on.

Metal nanoparticles to electromagnetic wave have special absorption effect, iron, cobalt, zinc oxide powder and carbon-coated metal powder can be used as high-performance millimeter-wave military stealth materials, visible light-infrared stealth materials and structural formula stealth materials, as well as cell phone radiation shield materials.

Cobalt content in the crust is not small, more than common lead metal and so on, the melting point of cobalt and iron is comparable, but the crust contain was significantly less than iron, so that it is destined to find later than iron, can be attracted. About cobalt, the ancient Greeks and Romans had used its compounds to manufacture beautiful deep blue color. The blue color on Chinese porcelain is due to the presence of cobalt compounds. All of these are showing that the ancient working people have long been use cobalt compounds.

The cobalt-containing blue ores-cobaltite CoAsS in medieval Europe is called kobalt, first appeared in the mineralogist writings who lived in the 16th century German. This word in German means "demon". This may be because of people think that this mineral is useless at that time. Today's cobalt, the Latin name is cobaltum and element symbols Co are from the Devon "demons".

In 1742, Swedish chemist studies cobaltite, they found an unknown metal (ie, cobalt), he put this metal into studying. In 1780, researchers have obtained pure cobalt, cobalt has been established as an element, in 1789 for the first time to include it in the periodic table.

Article Source:http://www.mhcmp.com

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Created on Dec 31st 1969 18:00. Viewed 0 times.

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