Hydrothermal extraction of potassium from potassic quartz syenite and preparation of aluminum hydroxide

Potassic quartz syenite, composed of microcline and quartz, is a promising source for the recovery of potassium, alumina, and silica values. Hydrothermal extraction of potassium by dissolution of the potassic quartz syenite powder in NaOH solution and utilization of alumina and silica in the potassic quartz syenite powder for preparation of acicular wollastonite and aluminum hydroxide were explored in this research. It mainly contains alkali-hydrothermal process, causticization process, and low-lime sintering process. The samples were characterized by using wet chemical analysis, X-ray diffraction, and scanning electron microscopy. The results indicated that the optimal extractions of K2O and SiO2 from the potassic quartz syenite powder were 93.2% and 62.5%, respectively. The purities of as-prepared acicular wollastonite, potassium carbonate, and aluminum hydroxide were 93.8%, 96%, 99%, respectively. The approach presented in this work is a promising process of comprehensive utilization of potassic silicate minerals such as K-feldspar. (C) 2015 Elsevier B.V. All rights reserved.