Preparation and Characterization of Novel 5Mg(OH)₂·MgSO₄·7H₂O Whiskers

Herein, novel monodisperse basic magnesium sulfate whiskers (5Mg(OH)₂·MgSO₄·7H₂O) were prepared under low-temperature and atmospheric-pressure conditions, using the admixture sodium citrate. X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, selected area electron diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the structure and morphology of the whisker products. The analysis results showed that the product was composed of high-purity basic magnesium sulfate whiskers. The lengths and diameters of the whiskers were 10-20 μm and 0.1-0.2 μm, respectively, and their aspect ratios were higher than 30. The formation mechanism of 5Mg(OH)₂·MgSO₄·7H₂O involved direct assembly from the precursors without the formation of magnesium hydroxide for redissolution. High-purity MgO whiskers with smooth surfaces were prepared using the as-prepared whisker products via thermal decomposition. Thus, the findings of this study can provide technical support for the cost-effective industrial-scale preparation of basic magnesium-sulfate whiskers and associated whisker products.