Hydrothermal Synthesis Process of Magnesium Oxysulfate Whiskers

Magnesium oxysulfate whiskers (5Mg(OH)2·MgSO4·3H2O) with a diameter of 0.5-1.0μm and a length of 30-50μm were synthesized via precipitation in room temperature followed with the hydrothermal reaction, using MgSO4 and NaOH as the raw materials. The experimental results indicate that the addition of magnesium hydroxide increases the specific conductance of the magnesium sulfate hydrothermal solution obviously, implying that magnesium oxysulfate whiskers may be formed via the dissolution of Mg(OH)2 followed with the interaction of Mg2+, SO42- and OH- ions. The hydrothermal process of the whiskers is controlled by the crystal growth step and the corresponding kinetic model is as follows: -dc/dt = 0.438(c - 0.417)4.