Brucite [molecular formula: Mg(OH)2] is a natural mineral with rich crystal water. When heated to 340癈, it will decompose into MgO, and produce plenty of hydrosphere. MgO is a high temperature resistant material, and that water can prevent flame spreading, this is flame-retardant mechanism of magnesium hydroxide. At present, halogen flame retardant is still used in many fields, although it can release the poisonous gas, causes 搒econd disaster?as fire occurs. Inorganic hydroxide flame retardant agent decomposes plenty of hydrosphere and absorbs lots of heat energy when it is burning, and forms a 揷eramic slipcover?on the burning object. Smoke, poisonous gas and corrosive gas, then be absorbed, it can solve 搒econd disaster?effectively. The temperature span of the hydroxylation of magnesium hydroxide is small, which makes hydrosphere release easily and has perfect fire retardant effect. Magnesium hydroxide flame retardant agent is becoming more and more popular with ideal flame-retardant, curb-smoke and filling effect.