In order to improve its dispersion performance and flame retardant effect, magnesium hydroxide can be better used in the flame retardant of plastics and other composites, magnesium hydroxide as a flame retardant There are special requirements, such as small surface area, not easy to form agglomeration, good compatibility with polymer materials, easy to disperse and other characteristics. Correspondingly, for the production of magnesium hydroxide flame retardant, it is necessary to adopt a different preparation technology from ordinary magnesium hydroxide. In normal temperature synthesis, the bases used are different. There are 3 methods: sodium hydroxide method, ammonia method and calcium hydroxide method.

As a flame retardant, ordinary magnesium hydroxide has its own unavoidable shortcomings: poor compatibility with polymers, it is easy to cause the processing performance of the polymer to decrease, and the physical properties and mechanical properties of the matrix material are decreased, so it cannot be enough to be used as a flame retardant.

The sodium hydroxide method takes brine or magnesium chloride as raw material, reacts with sodium hydroxide to obtain magnesium hydroxide; takes brine or magnesium chloride as raw material, takes brine as precipitant, and reacts in the reaction kettle is called Ammonia precipitation method; calcium hydroxide precipitation method is a method in which brine or magnesium chloride and other soluble magnesium salts are used as raw materials to react with lime milk to form Mg(OH)! Precipitation. The products obtained by the sodium hydroxide method and the ammonia method have high purity; in the calcium hydroxide precipitation method, calcium hydroxide is cheap and easy to obtain. This method has high industrial application value, but it is only suitable for industries that do not require high purity. use. After the magnesium hydroxide is prepared, post-treatments such as hydrothermal treatment and surface modification of the magnesium hydroxide are required.