Abstract: Magnesium hydroxide is an important magnesium-based mineral material and one of the ways to realize the high-value utilization of magnesium resources. However,the morphology change of magnesium hydroxide is affected by the raw materials,methods and conditions of preparation,which directly affects the application of magnesium hydroxide. Therefore,the preparation process,advantages and disadvantages of physical crushing method,direct precipitation method and magnesium oxide hydration method are analyzed in detail. It is pointed out that magnesium hydroxide has the characteristics of high thermal stability and large specific surface area,and the relationship between the morphology of magnesium hydroxide and its application in different ways such as flame retardant of polymer materials,adsorption treatment of heavy metal wastewater and degradation of dye wastewater,so as to provide reference for more potential applications of magnesium hydroxide. It is proposed that in the process of crystal growth of magnesium hydroxide,the growth habit of crystal plane can be changed by adding crystal plane regulating agent and doping cation,and the change of supersaturation of solution can also promote or inhibit the nucleation and growth of crystal,thus affecting the morphological change of magnesium hydroxide. It is pointed out that the industrial production of magnesium hydroxide with high purity and specific morphology is still facing challenges. The formation mechanism of magnesium hydroxide crystal defects under different conditions is not clear. It is still necessary to further study the types of dislocations and interstitial defects that may exist in the crystal to improve the performance of magnesium hydroxide and expand the field of high-value utilization of magnesium resources.

Key words: magnesium resources,magnesium hydroxide,morphology,crystal growth