Preparation of Different Diameter Nano-Mg(OH)2Powders and Their Non-isothermal Kinetics of Thermal Decomposition

The 0.1 mol•L−1MgSO4 liquor and 5 mol•L−1 NaOH liquor were prepared by MgSO4·5H2O and NaOH as raw materials, and then different diameter nano-Mg(OH)2 powders were prepared by chemical precipitation. The DTA-TG curves data obtained was by SDT 2960 simultaneous DSC-TGA analysis apparatus. The mensuration conditions were that rise temperature velocity was 15°C·min−1, gas was air. The kinetics was calculated by DTA-TG curves data and kinetics model. The results shown that nano-Mg(OH)2 powders shape were stick or spherical, their diameter were 7, 12, 20, 40, 70 nm. Their thermal decomposition reaction apparent activation energies were 188.065, 195.935,202.493, 210.178, 297.527KJ·mol−1, the apparent activation energy increase with Mg(OH)2 diameter. Their frequency factors were 2.721 × 1015, 9.246 × 1015, 4.251 × 1016, 6.067 × 1016, 3.866 × 1023, the frequency factors increase with diameter Mg(OH)2. Their reaction progression were 0.8296, 0.9321, 0.8743, 1.0275, 0.8903, the reaction progressions were fluctuated ...