Magnesium chloride is most commonly used for dust control and road stabilization. Its second-most common use is ice control. In addition to the production of magnesium metal, magnesium chloride also is used for a variety of other applications: fertilizer,mineral supplement for animals, wastewater treatment, wallboard, artificial seawater, feed supplement, textiles, paper,fireproofing agents, cements and refrigeration brine. Mixed with hydrated magnesium oxide, magnesium chloride forms a hard material called Sorel cement.
This compound is also used in fire extinguishers: obtained by the reaction of magnesium hydroxide and hydrochloric acid (HCl) in liquid form along with water in gaseous state. Magnesium chloride also is used in several medical and topical (skin related) applications. It has been used in pills as supplemental sources of magnesium, where it serves as a soluble compound that is not as laxative as magnesium sulfate, and more bioavailable than magnesium hydroxide and magnesium oxide, since it does not require stomach acid to produce soluble Mg2+ ion. It can also be used as an effective anesthetic for cephalopods, some species ofcrustaceans, and several species of bivalve, including oysters. MgCl2 is also commonly utilized in the polymerase chain reaction(PCR). The magnesium ion is necessary for both in vivo/vitro DNA synthesis.