Preparation of magnesium hydroxide flame retardant from light calcined powder by ammonia circulation method

Lamellar magnesium hydroxide (MH) with a purity of 99.5% was synthesized using industry lightly calcined powder as raw material and ammonium salt solution as circulating mother liquid by ammonia circulation method. The structures and morphologies of MH were characterized by X-ray diffraction, scanning electron microscope, laser particle size analyzer and thermo gravimetric analysis. The experimental results showed that the hexagonal flake MH products were about 0.86 μm in mean particle size (D50) and nanometers in thickness, and were loose enough for filtering. The BET surface area was about 8 m2∙ g− 1, indicating that the products can be applied as additives of the macromolecule compounds. The diffraction intensity of the (001) direction was higher than that of the (101) direction and the decomposition temperature of products was about 400 °C.