Separation and Purification of Fluorine from Fluorine Slag and Alkali Leaching Conversion Mechanism

This work proposes a novel and direct alkaline leaching process for extracting and recovering fluorine from fluorine slag, designed to overcome the current limitations in research on fluorine slag and the unclear leaching mechanisms. 80.40% of fluorine can be leached from the fluorine slag to the solution under optimal leaching conditions (NaOH 3.0 mol/L, temperature 80 °C, time 2 h, liquid-to-solid ratio 18 mL/g, and speed 800 r/min). The leaching kinetics of fluorine from fluorine slag in a concentrated NaOH solution was analyzed using multiple models, and key kinetic parameters, including activation energy and reaction order, were determined. The factors limiting fluorine leaching were identified through density functional theory calculations. Additionally, the economic feasibility of the process was evaluated, providing important insights into its potential for industrial application. This research aims to establish a foundation for optimizing processes and conducting mechanistic studies on the recovery of fluorine resources by leaching fluorine slag.