Feng Nie

Preparation and Characterization of Mg(OH)2 Flame-Retardant with Particular Morphology via Hydrothermal Process

The process of preparing magnesium hydroxide flame retardants with particular morphologies after hydrothermal treatment in the presence of organic modifier ethanediamine was mainly investigated. Influences of such factors as slurry concentration, modifier solution concentration and reaction temperature were studied. Meanwhile, the hydrothermally treated results were characterized by XRD, SEM, FTIR and TGA. The results indicate that when the reaction temperature was 180°C, and the reaction time ranges from 4 to 8 hours, the magnesium hydroxide and organic modifier solution concentration separately was 5% and 4 mol/L, a spherical crystalline magnesium hydroxide that has a symmetrical and regular crystal morphology was prepared. Such magnesium hydroxide materials were found to give an enhanced powder filtration.

Influence of Raw Material Concentration on Product Characterization of Magnesium Hydroxide Prepared via Ammonia Method

Magnesium hydroxide was prepared through direct precipitation using magnesium chloride and ammonia as raw materials. In this paper, we mainly studied the effects of magnesium hydroxide on product characterization when the concentration of raw materials was changed. The products were characterized through laser light particle size analysis, scan electron microscope and X-ray diffraction. The study showed that a sudden change in the morphology of magnesium hydroxide products and in the polarity of the crystal occurred under the following conditions: stirring speed of 2500 rpm, reaction temperature of 60°C, ammonia to magnesium chloride ratio of 2:1, ammonia addition rate of 20 mL/min, and aging time of 30 min. As the raw material concentration was changed, the morphology of magnesium hydroxide products and the polarity of the crystal exhibited sudden change. When the concentration of magnesium chloride was changed to 0.8 mol/L, the product demonstrated a flower-like globular structure, the largest size, and the minimum polarity. When the concentration of magnesium chloride was more than 1 mol/L, the product exhibited a flake structure, no obvious aggregation and a narrow particle size distribution.