Preparation of magnesium hydroxide flame retardant

In order to improve its dispersive property and flame retardant effect, magnesium hydroxide can be better used for flame retardant of plastics and other compounds. As a flame retardant, magnesium hydroxide has special requirements, such as small surface area, not easy to form into a group, good compatibility with polymer materials, easy to disperse and other characteristics.For the production of magnesium hydroxide flame retardant, it is necessary to adopt a different preparation technology than ordinary magnesium hydroxide.In normal case synthesis at room temperature, according to the different types of base used.There are three methods: sodium hydroxide method, ammonia method and calcium hydroxide method.

Common magnesium hydroxide as a flame retardant has its own inevitable disadvantages: poor compatibility with high polymer, easy to cause high polymer processing performance, matrix material physical and mechanical properties have been reduced, so it can not be used as a flame retardant.

The sodium hydroxide method is based on the reaction of brine or magnesium chloride with sodium hydroxide to produce magnesium hydroxide.Taking brine or magnesium chloride as raw material and brine as precipitant, the reaction method in the reaction kettle is called ammonia precipitation method.Calcium hydroxide precipitation method is based on brine or magnesium chloride and other soluble magnesium salts as raw materials, so that the reaction with lime milk to produce Mg(OH)!Precipitation method.The purity of products prepared by sodium hydroxide and ammonia method is high.In 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 the industries with low purity requirement.After the preparation of magnesium hydroxide, magnesium hydroxide should be treated with water heat treatment and surface modification.