Regardless of  home or overseas, the magnesium application mainly concentrates in three big domains: the aluminum alloy production, the compression casting production, the steel-making desulphurization, and also used in the fields of rare earth alloy, the metal return and other domains.  
  Because of the small density of magnesium, the high specific tenacity, and can constitute with metal like aluminum, copper, zinc and so on to make high strength alloy, the magnesium is the important alloying element. In the world the biggest expense domain of magnesium is to be the alloy increase element for aluminum. In 2002 the world altogether used 145,600 tons magnesium for the aluminum alloy, accounted for 40% of the total mg consumption; in 2003 China altogether used 21,000tons magnesium for the aluminum alloy, accounting for 41% of the total use. Generally speaking, the expense ratio magnesium and the original aluminum is approximately 0.4%.
  In 2002 original magnesium used in the compression casting accounts for 35% of the mg expense. In the magnesium compression casting production profession, North America, Latin American and the Western Europe used the most, because the automotive industry promoted the market for the magnesium .The related statistical figure indicated that, in the past 10 years, the magnesium alloy used in the field of pressed  casting rise about 15% , moreover this kind of development tendency will continue.
  In Europe, America and Russia, many steel mills used the magnesium for desulphurization. In 2002, 57,300 tons original magnesium was used for the steel desulphurization, accounts for the 15.70% of the total use.
  in 2003  China used 8,000 tons magnesium in the field of the steel and iron desulphurization, accounting for 15.62% of the total consumption quantity . Magnesium grain has a better desulphurization effect compared with calcium carbide. Although the magnesium price is higher than the calcium carbide, its amount used is the calcium carbide 1/6 -1/7, so Mg is more economical. Generally speaking, ton steel consumed magnesium grain of 0.4 - 0.5 kilogram, after the desulphurization the sulfur quantity is 0.001 - 0.005%.
  Magnesium can be used as sacrificed anode for the cathodic protection, which is one effective way to prevent the metal from corrosion. The way has the characteristics like: good performance for anticorrosion; does not need the sur- direct-current power; automatic effect after the installment; does not have to maintain the equipment, take a little area, the project expense is low; does not have any disturbance with the external environment.