See also: Mg
The magnesium is a chemical element, of symbol Mg and Atomic number 12.
Magnesium is a alkaline-earth Métal. It is the eighth most abundant element of the Earth's crust, the third metal behind the Aluminum and the Fer. It is also the third component of the salts dissolved in the Sea water.
In England, Joseph Black recognized magnesium like an element in 1755, and Humphry Davy isolated the pure metal form by electrolysis in 1808 starting from a mixture from Magnésie and oxide HgO mercury.
In solution, it forms Mg2+ ions.
It ignites with difficulty in the form of block, but very easily if it is tiny room in small chips. Out of powder, this metal warms up by oxidation and ignites when it is exposed to the air. It burns with a very luminous luminous flame, from where its use for the flashes at the beginnings of the Photographie.
Magnesium is largely employed in alloys containing aluminum intended for the plastic deformation, being used for the manufacture of sections, or the drink quills, which consumes significant amounts of them.
The lightness of magnesium and its mechanical characteristics make it invaluable for particular uses as the realization of small resistant cases, of cases of laptops or top-of-the-range cameras. Used mainly in aeronautics, the magnesium alloys start to extend in other branches of industry, in particular in auto industry where the policy is currently to minimize the weight of the vehicles in order to reduce consumption while carburizing. However, making of these alloys at base magnesium is difficult and dangerous since finely divided magnesium (droplets of liquid magnesium, powders magnesium) can ignite or explode with the contact with the atmosphere or of water.
Magnesium is also used as reagent in chemical industries and pharmaceutical.
Alloys containing magnesium are also used for to carry out castings for the Automobile S and the machines.
Alloys magnesium-calcium are used in the metallurgy of the Plomb (for the débismuthage).
Compounds of magnesium, mainly the Magnesia MgO, are employed like refractory Material for the garnishing of furnaces (glass, cement), in the metallurgy of the Fer, the Acier non-ferrous or other metals.
The magnesia and others made up are employed in agricultural, chemical industries and of the building, like in the sport, in particular in gymnastics and climbing.
The contribution recommended daily is estimated at 300 magnesium Mg per day (double for the sportsmen or the expectant mothers) or 6 mg/kg of weight.
The body does not produce magnesium. Excessive consumption would be eliminated naturally by the organization. The ingestion of great quantities of magnesium shows Diarrhée S. magnesium is effectively filtered by the kidneys in the adult, but poisoning by magnesium excess can exist at the child and in the case of impaired renal functions.
The magnesium hydroxide (Mg (OH) 2), obtained while making react the sodium hydroxide on the magnesium salt, is employed in medicine like Laxatif (magnesia milk), like in the refining of the Sucre.
They are followed closely by the cocoa with 150 to 400 Mg for 100 G) and complete cereals containing 100 with 150 Mg for 100 G. On the other hand the acid Polysaccharide S and phytic that they contain harm their absorption, especially in the case of the wholewheat bread with the Levure, but not in the case of the wholewheat bread with the Levain which destroys these acids partially.
The spinach S contain of 50 with 100 Mg for 100 G, but contain Oxalic acid which gene also their assimilation.
Lastly, the fish, the meat offals and the bolted cereals contain of 25 with 50 magnesium Mg for 100 G.
Some food containing of magnesium: Green vegetables, buckwheat, Broad bean S, Almond S, salt of Nigari (magnesium chloride of origin marinades), Banane.
The principal magnesium producers are the Russia, the China and the North Korea (each one responsible for approximately 20 % of the worldwide production).
From the various ores or brines containing of magnesium, in the form of chloride, from carbonate, oxide, metal is extracted by processes from the type electrolysis or electrometallurgy
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