Magnesium hydroxide is a medium-strong alkali (magnesium hydroxide solubility is very small, the alkalinity of the solution is very weak, sometimes treated as a weak alkali), heated to 623K (350), that is, dehydrated and decomposed, soluble in acid or ammonium salt solution. Like magnesium oxide, it easily absorbs carbon dioxide in the air and gradually forms basic carbonates. It decomposes into magnesium oxide and water above 350, but can only be completely dehydrated above 1800.
Magnesium hydroxide is an excellent flame retardant for plastic and rubber products. In terms of environmental protection, it can be used as a flue gas desulfurizer, and can replace caustic soda and lime as a neutralizer for acid-containing wastewater. It is also used as an oil additive to play the role of anti-corrosion and desulfurization. In addition, it can also be used in the electronics industry, medicine, sugar refining, as insulation materials and other magnesium salt products.
Magnesium hydroxide has excellent buffering properties, reactivity, adsorption capacity, thermal decomposition properties, etc., which can be used as chemical materials and intermediates, as well as a green flame retardant and additive for rubber, plastics, fibers and resins and other polymer materials industry. Magnesium hydroxide is mainly used as a flame retardant, acid wastewater treatment agent, heavy metal remover, flue gas desulfurizer and so on in the field of environmental protection.
Magnesium hydroxide can be used as a flame retardant or flame retardant filler to be added to polyethylene, polypropylene, polystyrene and ABS resin, which has good flame retardant and smoke suppression effect, and the addition amount is 40 20 parts. However, the surface of the particles needs to be treated with anionic surfactants, and inexpensive anionic surfactants such as high-grade fatty acid alkali metal salts or alkyl sulfates and sulfonated succinates can be used, with a dosage of about 3%. The product is also used in the manufacture of magnesium salt, the refining of sugar, the pharmaceutical industry, daily chemicals, etc.
The surface modification of magnesium hydroxide must be carried out to improve its compatibility with the polymer base material, so that the mechanical properties of the filler material are not reduced, and even some of the mechanical properties of the material are improved.