Hydrothermal Modification of Mg(OH)2 Particles in NaOH Solution
氢氧化钠溶液中氢氧化镁的水热改性

The hydrothermal modification behavior of Mg(OH)2 particles in aqueous NaOH solution was investigated, with focus on the influence of NaOH concentration on the morphology, crystalline structure and dispersion properties of the hydrothermal products. Regular hexagonal plates of Mg(OH)2 with uniform size and smaller specific area were formed after hydrothermal treatment. The dispersion properties of the hydrothermal products were improved owing to the alteration of growth direction for Mg(OH)2 crystals, resulting in the increase of I(001)/I(101). Under the experimental conditions (1.5 mol/L of NaOH), the increase of NaOH concentration is favorable to the hydrothermal modification of Mg(OH)2 particles. Thermodynamic calculation indicated that in the Mg(OH)2 NaOH-H2O system, the concentration of OH- ions was much higher than that of soluble Mg-bearing species Mg(OH)2(aq), MgOH+ and Mg2+]. The improvement for the hydrothermal modification of Mg(OH)2 in the comparatively concentrated NaOH solution may be attributed to the increase of OH- concentration.