Improved understanding of Sodium hydroxide concentration role and kinetic model of cryolite reactive extraction in cathode Spent Pot Linings

Abstract Spent Pot Lining (SPL) cathode pot, waste from the aluminium smelting process needs detoxification cyanides, washing out water-soluble salts and extraction of cryolite (Na 3 AlF 6 ) decomposition products to be recycled. Revealed mechanism with NaOH opens possibilities explore its critical role in reactive process. Common Na + ion hinders solubility product but also drives mass transfer reaction site. Reaction balance provides adequate liquid solid ratio (L/S) concentration range. A newly developed kinetic model based on Whitman film theory flow enables prediction time decompose a low enough level. Results show that internal particle resistance transport (1/k s is 19 times larger than external l one governs whole