Magnesium

It occurs in nature in several minerals such as magnesite (MgCO₃), dolomite (CaCO₃, MgCO₃), kieserite (MgSO₄ · H₂O) and carnalite (MgCl₂ · KCl · 6H₂O). The metal is prepared by the chloride or oxide process. The oxide process is not in use anymore.

In the chloride process, a melted mixture of chlorides of sodium, potassium and magnesium is electrolysed. To prevent decomposition of magnesium chloride during the heating process, alkali chloride should be present. When the magnesium rises during liberation, it rises to the surface and has to be ladled out. If there is a need for pure magnesium, it is prepared by distillation.

The properties of magnesium are as follows:

1. It is the lightest material.
2. It can be readily machined.
3. It hardens very rapidly with cold working.
4. It is easily attacked by weak acids and even by saline solution.
5. It ignites easily.
6. It can be welded.