Electrochemical Reduction and Dissolution of Aluminium in a Thin-Layer Refinery Process

Abstract

The liquid metal refining industry has a demand for new technologies operated at low energy consumption and environmental impact nowadays. This work addresses an approach for Al purification and extraction from scrap in a thin layer of the multiple-capillary molten salt electrochemical system. The two types of single-capillary cells with quasi-reference electrodes were used to study the kinetics of aluminium reduction and dissolution in a narrow (O x length) 1 × 1 and 1 × 5 mm channel filled with liquid LiF-AlF3 or equimolar NaCl-KCl with the AlF3 addition at 850 °C. A multiple-capillary Al refinery process can be designed to significantly reduce the specific energy consumption. The new refinery process can be performed at high current densities. The single-capillary electrolysis can be used for kinetics studies. Thin-layer cells should be operated at a thickness no more than 5 mm to compensate the high resistance which may vary in the range from 0.7 to 2.5 Ω at this capillary length. The 64LiF-36AlF3 melt can be used as an electrolyte for the thin-layer electrolysis due to the high electrical conductivity, the wide potential window between Al and Li reduction, and the low liquidus temperature.