Magnesium sulfide reacts with oxygen to form the corresponding sulfate, magnesium sulfate. MgS reacts with water to give hydrogen sulfide and magnesium hydroxide. In the BOS steelmaking process, sulfur is the first element to be removed. Sulfur is removed from the impure blast furnace iron by the addition of several hundred kilograms of magnesium powder by a lance. Magnesium sulfide is formed, which then floats on the molten iron and is removed. MgS is a wide band-gap direct semiconductor of interest as a blue-green emitter, a property that has been known since the early 1900s. The wide-band gap property also allows the
Magnesium stearate processes. In the creation of pressed candies, magnesium stearate acts as a release agent and it is used to bind sugar in hard candies such as mints. Magnesium stearate is a common ingredient in baby formulas. Magnesium stearate is a major component of "bathtub rings." When produced by soap and hard water, magnesium stearate and calcium stearate both form a white solid insoluble in water, and are collectively known as "soap scum." Magnesium stearate is generally considered safe for human consumption at levels below 2500 mg/kg per day and is classified in the United States as generally recognized as safe