Uses of Magnesium Metal and Compounds

In all work with magnesium the risk of fire deserves attention. If magnesium starts to burn, water must not be used in an attempt to extinguish it, as this makes the situation worse. At the high temperature, magnesium is oxidized by the water, hydrogen is evolved and the fire becomes explosive. An incipient fire must instead be put out with sand, which keeps the air out. 

In new research projects, non-combustible magnesium alloys are being developed. Investigations of the effect and mechanism of elements that may suppress the combustibility of magnesium are continuing. Calcium has been mentioned as an alloying element. 

Magnesium is an important alloying metal for aluminum, as, for instance, in the alloy AA 5052 with 2.5% Mg. In fact 43% of the total magnesium metal produced in 2000 was used for such alloying purposes. Different magnesium cast alloys accounted for 34%, while 13% was used for desulfurization in the iron and steel industry. World production was 430 000 tonnes and the figure is increasing aimually. 

Magnesium oxide MgO, obtained by calcination of magnesite, is mainly used as a refractory material for lining furnaces for iron and steel production as well as for the manufacture of glass and cement 

A special but very important use of magnesium is for alkylation reaction in organic synthesis (alkyl groups R are methyl CHj, ethyl C Hj, propyl CjH, etc.). Organometallic compounds are used as tools for these syntheses. They are readily formed when alkyl halides (RCl, RBr, RI) react with metals of low electronegativity, in particular magnesium  

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