Preparation of nano-magnesium hydroxide and heavy magnesium oxide by ammonia brine process

Our country is rich in brine resources, in addition to a large amount of sodium chloride, brine also contains rich magnesium ions, so brine can be used as a high-quality magnesium source. However, the utilization rate of brine in China is still low, which causes a large waste of resources and also pollutes water resources, which is not conducive to environmental protection.

In addition, our country\’s magnesium development and manufacturing technology is relatively backward, most of the products produced are primary products, the added value of the products is low, cannot meet some fine use, and the economic benefits are poor. Therefore, it is very important to develop and utilize the magnesium resources in brine to produce high quality magnesium compounds. Magnesium hydroxide and magnesium oxide are important members of magnesium compounds, and they have become a hot topic of research because of their wide range of applications.

Magnesium hydroxide is an excellent filler copolymer flame retardant, and has important applications in medicine and environmental protection, such as as antacid, drug excipient, used in flue gas desulfurization, wastewater neutralization and decolorization treatment, adsorption of heavy metals, etc. In addition, magnesium hydroxide can also be used as a raw material for the production of other magnesium compounds. Magnesium oxide is widely used in national defense, aerospace, construction, electronics, communication, metallurgy, ceramics, paint, light industry, textile, medicine, feed, agriculture and other industries.

Since the crystalline shape and particle size distribution of magnesium hydroxide and magnesium oxide products have a great influence on their applications, ultra-fine/nano magnesium oxide and magnesium hydroxide will become the focus of research in order to better perform their functions. Although there are many methods for the preparation of ultrafine, nano magnesium hydroxide and magnesium oxide, the liquid phase precipitation method is the most commonly used method considering the operational feasibility, economic applicability and other practical factors. The liquid-phase precipitation method usually uses magnesium salt as the reaction raw material, and sodium hydroxide, ammonia, lime milk and other alkaline substances as the precipitant.