What is alumina trihydrate?

Alumina trihydrate (Al(OH)3) is also called aluminum trihydroxide or aluminum hydrate. It is a white, odorless, and non-toxic powder that occurs naturally as the mineral gibbsite. Alumina trihydrate is produced by the reaction of bauxite ore with caustic soda, resulting in the precipitation of aluminum hydroxide.

Alumina trihydrate is widely used as a flame retardant and smoke suppressant in a variety of applications, including plastics, rubber, cable insulation, and textile fibers. As a result of its high specific surface area and low particle size, alumina trihydrate is also used as a filler and pigment in paints, coatings, and adhesives. It is additionally used in the production of ceramics, glass, and catalysts.

Alumina trihydrate decomposes at temperatures around 200°C, releasing water vapor, and converting into aluminum oxide. The high water content of alumina trihydrate provides a cooling effect when exposed to fire, making it an effective flame retardant. As a result of its non-toxic properties, it is used in food-grade applications as an anti-caking agent.