The invention discloses a method for preparing high-whiteness
magnesium hydroxide by removing impurities from
brucite in the field of inorganic nonmetallic
mineral processing. The method comprises the following steps: crushing
brucite raw ore into superfine
powder, and mixing the superfine
powder with a dispersing agent to prepare
slurry; adding a complexing agent to remove impurities through a flotation process; carrying out modification reaction on the floated
slurry and a specially-made sulfydryl-carboxyl
bifunctional silicon-
titanium composite oxide under an alkaline condition; and finally, stabilizing through a
coupling agent and
drying to obtain a high-whiteness product. The modified substance is prepared from cyanopropyl
silane and
titanate through
hydrolysis, conversion of cyano groups into carboxyl groups,
sol-gel conversion and
calcination, and the unique
bifunctional structure of the modified substance can effectively recognize and coat coloring impurities. The process is simple and environment-friendly, and the obtained
magnesium hydroxide product is high in whiteness, good in
dispersity and suitable for the field of high-end
flame retardant and composite materials.