Utilization of the MgO-Rich Residue Originated from Ludwigite Ore: Hydrothermal Synthesis of MHSH Whiskers

作者：Li, Guanghui; Fang, Li; Zhang, Xin; Liang, Binjun; Rao, Mingjun^*; Peng, Zhiwei^*; Jiang, Tao

来源：Minerals, 2017, 7(8): 138.

DOI：10.3390/min7080138

• magnesium hydroxide sulfate hydrate whiskers
• hydrothermal synthesis
• ludwigite ore
• magnesium

In this work, from the MgO-enriched residue originated from ludwigite ore, value-added magnesium hydroxide sulfate hydrate (MHSH) whiskers were prepared via sulfuric acid leaching and leachate purification, followed by hydrothermal synthesis. During sulfuric acid leaching, 98.2% magnesium and 99.6% silica were removed under the optimal leaching conditions: sulfuric acid concentration of 40%, leaching temperature of 80 degrees C, leaching time of 90 min, and liquid to solid ratio of 4 mL/g. After purification of the acidic leachate via oxidation and precipitation to remove impurities including iron and aluminum, the Mg2+-rich solution was used to prepare magnesium hydroxide sulfate hydrate whiskers (5Mg(OH)(2)center dot MgSO4 center dot 2H(2)O, abbreviated as 512MHSH) via hydrothermal synthesis. Finally, 512MHSH whiskers were obtained with 30-100 mu m in length, 0.5-1.0 mu m in diameter and aspect ratio of approximately 100. The physicochemical characteristics of whiskers were further characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS), Fourier Transform Infrared Spectroscopy (FT-IR) and Thermogravimetry-Differential Scanning Calorimetry (TG-DSC).

• 单位
  中南大学