What are the best sources for magnesium?
Magnesium is actually quite a common element - making up 2.5% of the earth's crust. The biggest uses for magnesium are for its compounds. The biggest single user being the steel industry which uses calcined dolomite (calcium magnesium carbonate) as a flux. This makes dolomite the biggest single ore for magnesium. The second biggest ore is magnesite - more or less pure magnesium carbonate. About 20 million tons of magnesite are produced each year - as documented in link 1 below. Most magnesite goes into fillers - your toothpaste is mostly magnesite - as is the white stuff making up most of the pills that carry prescription and non prescription drugs. Magnesium oxide is made into refractory bricks for lining furnaces. . Sea water is another source - but much smaller - about 2 million tonnes per year - made by reacting sea water with calcined dolomite. A lot of this magnesium ends up as magnesium chloride, which is used as a deicer and a de dusting agent on dirt roads. Dow Chemical had a plant in Freeport Texas which made magnesium metal starting from seawater. This plant started in 1943 and ran until 1999, when it could no longer stand the competition from China. . As for magnesium metal, annual production is about 750,000 metric tons per year - of which 85% comes from China. The source for the Chinese magnesium is magnesite ore. There are numerous different processes to make magnesium - most using electrolysis. It takes about 10 kW Hr of electricity to make one pound of magnesium. There has been a lot of activity about magnesium in Australia over the past 15 years and there are no less than eight major proposed projects to make magnesium metal. (See link 2). None has so far got into construction. Finally if you actually want to buy magnesium metal - try link 3.
