Magnesium hydroxide, it's not just a flame retardant
When a certain amount of flame retardant is added to the material, the flame retardant property of the material will be improved correspondingly, but often the mechanical properties or other properties of the material will be affected, and sometimes it will bring inconvenience to the processing. Therefore, in order to maintain the comprehensive performance of flame retardant composite, the comprehensive performance of flame retardant agent must be considered.
As a flame retardant material, magnesium hydroxide has many advantages:
(1) The decomposition temperature of magnesium hydroxide is high, the ignition point is higher than alumina hydroxide, improve the heating temperature of polymer materials;
(2) The MgO generated after combustion dehydration is a kind of refractory material, and is a kind of alkaline oxide, can absorb acid gas;
(3) Strong heat absorption capacity, high flame retardant efficiency;
(4) Low cost, easy to process in different polymer materials.
In recent years, magnesium hydroxide as a kind of green flame retardant, the dosage is very large.
The use of magnesium hydroxide
Magnesium hydroxide has been widely used in the field of flame retardant and environmental protection. In addition, because magnesium hydroxide slurry has high activity, good adsorption performance, easy to adjust and control, magnesium hydroxide can be used as a neutralizer for acidic waste liquid and sulfur-rich oxide treatment, heavy metal removal, improve the acidity of soil, can also be used as an antacid for pharmacy, fertilizer additives, etc.
Flame retardant applications
Magnesium hydroxide is an important halogen-free environmental protection flame retardant. The flame retardant mechanism is to generate stable coating magnesium oxide and water vapor, and the flame retardant efficiency is low. In order to achieve good flame retardant effect, the addition amount is generally as high as 50%~60%. The usual method is surface modification of magnesium hydroxide and synergistic effect of magnesium hydroxide.
Magnesium hydroxide flame retardants can be used not only alone, but also in combination with other synergistic agents, such as magnesium hydroxide/red phosphorus, magnesium hydroxide/zinc borate, magnesium hydroxide/carbon nanotubes and magnesium hydroxide/carbon black. The synergistic flame retardancy of magnesium hydroxide can not only achieve better flame retardancy effect, but also reduce the amount of flame retardants, thus reducing the cost.
Application in environmental protection field
(1) Treatment of acid-containing wastewater
The neutralization reaction rate of magnesium hydroxide is slow, and the particle size produced after the neutralization reaction is large and quickly subsides. Magnesium hydroxide in the treatment of acid containing wastewater can realize the simplification of operation process, the reduction of operation time, good controllability and the reduction of treatment cost.
(2) Removal of heavy metals
Due to the large specific surface area of magnesium hydroxide particles, it has strong adsorption capacity, and can remove environmental harmful Ni2+, Cd2+, Mn2+ and other heavy metal ions from the waste liquid of industrial wastewater. Other heavy metal elements such as Mo, Co, Fe, W and V can also be removed by magnesium hydroxide, light burned magnesium oxide or magnesium aluminum carbonate.
(3) Flue gas desulfurization
At present, there are nearly 20 kinds of mature desulfurization technologies, among which magnesium hydroxide desulfurization technology is economical and practical, and has a good development prospect in the future. The advantages of magnesium hydroxide desulfurization process include high desulfurization efficiency, low investment cost, low operation cost, high comprehensive benefit, reliable operation and no secondary pollution.
