Magnesium Chloride

Brief Overview
Magnesium Chloride (MgCl2) is a faint-white to colourless crystalline salt which are ionic halides. Magnesium Chloride can be extracted from natural sources like brine or sea water in the form of Magnesium Chloride Hydrates. Magnesium Chloride has unique physical properties such as high water solubilities, high melting point (714 degrees Celsius) and good moisture absorptivity.

Manufacturing Process
There are two methods used for producing Magnesium Chloride:
Dow Process:
Magnesium Hydroxide (solid form) and Hydrochloric Acid (gas) is combined and reacted to give Magnesium Chloride in the form of a solution with water.
Using Sea Water/Brine:
The major raw material sea water, is combined with dolomite. This dolomite is converted to a mixture of various oxides by heating it at a high temperature. Calcium Hydroxide remains in the solution mixture while Magnesium Hydroxide precipitates out. This is then filtered and heated to form a pure form of Magnesium Oxide. This Oxide is then mixed with carbon and heated in an evaporator in the presence of a Chlorine gas stream to give Magnesium Chloride in solid form.

Construction
Due to its very high solubility/hygroscopicity in water, less damage to concrete, and less corrosion to metals, Magnesium Chloride solution is widely used as a de-acing agent on roadways in order to prevent ice from building up during winters. It is also used on roads for dust control and prevention from wind erosion.

Medicine Industry
It was used as an antiseptic in ancient days as it did not cause any tissue damage like other antiseptics. It is also used as an anaesthetic for crustaceans and cephalopods as it acts on the central nervous system without any damage. It is preferred over urethane or ethanol for use on cephalopods.

Agriculture
It is substituted for magnesium sulphate for foliar feeding to correct magnesium deficiency in plants. High concentrations of magnesium has been found to protect plants from bacterial infection.

Other Applications
It is utilized in various other applications. It is an important coagulant in tofu obtained from soy milk and in formula milk for infants, component in fire extinguishers (as a combination with Hydrochloric Acid and water in gaseous state), mineral supplement for animals, wastewater treatment, etc.