Metallothermic process
There are several thermic processes for the production of magnesium. All of them use calcined dolomite as ore and ferrosilicon as the reductant in a vacuum furnace.
  1. Pidgeon process (see fig.)
  2. Bolzano process (see fig.)
  3. Magnetherm process (see fig.)
The original process which was developed by L.M. Pidgeon in 1940 uses an eleven inch diameter retort that is externally heated. The magnesium evolves as a vapor and is condensed in the water cooled end of the retort. This process produces a very high purity magnesium and is used for example in Japan, India and Canada. The Balzano process uses internally heated retorts which allows the use of larger retorts and bigger batches. These are used in Italy and Brazil.

Other Magnesium production processes are:
  • AMC PROCESS, Australian Magnesium Cooperation