Potassium fixation and the separation from sodium through the formation of K-alunite using activated aluminum hydroxide

ABSTRACT

This report introduces a novel method of separating potassium from sodium by synthesizing K-alunite using activated aluminum hydroxide (Al(OH)₃). A two-step operation, consisting of the mechanochemical activation of Al(OH)₃ and subsequent hydrothermal processing at a low temperature of 80°C with Al₂(SO₄)₃ · 18H₂O and K₂SO4 or Na₂SO4, was conducted. K-alunite but not Na-alunite at this low temperature was successfully formed, leading to the possible separation of potassium sulfate from sodium sulfate more easily. The process may serve the purpose of recovering potassium from some aqueous alkali sources for providing potash fertilizer in agricultural application.

KEYWORDS:

• Activation
• aluminum hydroxide
• alunite
• potassium fixation
• separation