The Synergistic Extraction Kinetics of Aluminum and Silicon from High-Alumina Fly Ash by Carbochlorination

In light of the high alumina content (nearly 50%) in the high-alumina fly ash, high-alumina fly ash is considered a significant and promising alternative resource to bauxite. Towards the prevailing issues in the current process of extracting alumina from fly ash, a novel synergistic extraction of aluminum and silicon from high-alumina fly ash was proposed, which features carbochlorination with chlorine and carbon as raw materials. In this paper, the carbochlorination kinetics of aluminum and silicon was investigated. The results indicate that the carbochlorination process of fly ash conforms to the reaction model without generating solid byproducts. The carbochlorination of alumina and silica was governed by chemical reactions at 850–950 ℃, with an activation energy of 65.70 kJ/mol and 89.06 kJ/mol, respectively. The reaction series and the kinetic equation, which takes into account the temperature and partial pressure of chlorine gas were successfully determined.