Abstract:

Using polyvinylpyrrolidone as control agent,magnesium chloride,sodium hydroxide and ammonia as raw materi-als,a spherical magnesium hydroxide precursor was prepared through static reaction,and then spherical MgO was obtained by the calcination of the magnesium hydroxide.The effects of factors such as the type of control agent,the amount of control agent,the concentration of reactants and reaction time on the morphology of spherical magnesium hydroxide were studied,and the products were characterized by XRD,SEM and other analytical methods.The results showed that using 1.0% (mass fraction) polyvinylpyrrolidone as control agent,the concentration of magnesium chloride was 1.0 mol/L,the concentration of sodium hydroxide was 0.25 mol/L and the reaction time was 24 h,then the spherical magnesium hydroxide precursor was obtained.Spherical magnesium hydroxide precursor was calcinated to obtained spherical magnesium oxide under the condition of 600 ℃ and 2 h,the prepared spherical magnesium oxide particles had uniform size,good dispersibility,high sphericity and an average particle diameter of 4.53 μm.

Key words: spherical magnesium hydroxide, spherical magnesium oxide, polyvinylpyrrolidone