Abstract: 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⁺, SO₄^2- 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.

Key words: magnesium oxysulfate, whiskers, hydrothermal synthesis