Abstract: Industrial oxalic acid and magnesium hydroxide were used as raw materials aiming to prepare nano-sized magnesia by controlling the experiment conditions.Influences of calcination temperature,calcination time,reaction temperature,reaction time,oxalic acid concentration,and surfactant concentration on particle size of magnesia products were stu-died.Products were characterized by means of X-ray diffraction（XRD）,thermogravimetric differential thermal analysis（TG-DTA）,and scanning electron microscopy (SEM) etc..Results showed that when oxalic acid concentration was 0.8 mol/L,the concentration of surfactant was 1.0 mmol/L,reaction at 40 ℃ for 20 min,and calcination at 600 ℃ for 2 h,nano-sized magnesia with particle size about 50 nm can be obtained.The product prepared by this method has many advantages,such as high purity,simple process,convenient operation,less demanding on the equipment and technology, and easy-to-industrial production.

Key words: industrial oxalic acid, magnesium hydroxide, nano-magnesia