Hydrothermal process of synthetic gibbsite and the characteristics of Na in gibbsite crystal

The presence of Na in synthetic gibbsite was studied by several modern testing methods such as X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and inductively coupled plasma. Results show that Na is located between gibbsite crystals and is not present as sodium aluminosilicate hydrate in synthetic gibbsite. Synthetic gibbsite crystal can be transformed into boehmite under the hydrothermal condition of 210 °C for 60 min. During the reaction process, synthetic gibbsite crystal particles break up into small fragments and form boehmite. During the process, impurities are released and the Na can be removed by washing. Over 90% of Na can be removed during the hydrothermal transformation process. This technology can be applied in the production process of high-purity alumina.