氢氧化镁的制备及机理研究进展

Research Progress on the Preparation and Mechanism of Magnesium Hydroxide

氢氧化镁是重要的镁基矿物材料,是实现镁资源高值化利用的重要途径。然而,氢氧化镁的形貌变化受制备原料、方法及条件的影响,直接影响着氢氧化镁的应用。因此,对物理粉碎法、直接沉淀法、氧化镁水化法等制备方法的制备工艺及优缺点进行了详细分析,指出氢氧化镁具有热稳定性高、比表面积大等特点,分析了氢氧化镁形貌与其作为高分子材料阻燃、重金属废水吸附处理及染料废水降解等不同途径应用之间的关联,以期为氢氧化镁的更多潜在应用提供借鉴。提出了在氢氧化镁晶体生长过程中,可以通过添加晶面调控剂、掺杂阳离子等方式改变晶面生长习性,而且溶液过饱和度变化也会对晶体成核和生长产生促进或抑制作用,从而影响氢氧化镁的形态。指出工业化生产高纯度和特定形貌的氢氧化镁仍面临着挑战,不同条件下氢氧化镁晶体缺陷形成机制尚不明确,仍需进一步研究晶体中可能存在的位错、间隙缺陷等类型,以提高氢氧化镁的性能、扩展镁资源高值化利用领域。

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 ox-ide 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 applica-tion in different ways such as flame retardant of polymer materials,adsorption treatment of heavy metal wastewater and degrada-tion 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 produc-tion 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 dis-locations 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.