Effect of Mg2+ and Al3+ on Morphology and Size of Prepared Hemihydrate Calcium Sulfate Whiskers
Using calcium sulfate dihydrate as raw material,a hydrothermal method was employed to prepare calcium sulfate hemihydrate whiskers.Based on an investigation on the effects of reaction temperature and time on the morphology and size of the whiskers,a systematic study was conducted on the effects of Mg2+ and Al3+ concentrations on the morphology and size of the whiskers.The experimental results showed that under the conditions of slurry mass fraction of 2%,reaction temperature of 160℃,and reaction time of 6 h,the average length of the product prepared was 273.4 μm,and the average length-to-diameter ratio reached 30.4.The whiskers were needle-shaped and relatively uniform.In the presence of low concentrations of Mg2+,the diameter of the whiskers was smaller and the length-to-diameter ratio was higher.Al3+ had a strong inhibitory effect on the growth of calcium sulfate hemihydrate whiskers along the c axis,resulting in that whiskers were rod-shaped or spindle-shaped.
Calcium sulfate hemihydrateWhiskersHydrothermal methodLength to diameter ratio
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