How to produce aluminum foil from alumina

The production of aluminum foil from alumina (Al₂O₃) involves several industrial steps, including metallurgical refining, electrolysis, and precision rolling.

Here is a detailed description in English:

1. Extracting Alumina from Bauxite (Bayer Process) Alumina is first extracted from bauxite via the Bayer process: (1) Crushing and digestion: The bauxite is ground and mixed with hot sodium hydroxide (NaOH), the aluminum oxide dissolves into sodium aluminate, and impurities (such as iron oxide) form "red mud" waste.

(2) Precipitation and calcination: The solution is cooled, aluminum hydroxide (Al(OH)₃) crystals are added, and then calcined at about 1,200°C to produce pure aluminum oxide (Al₂O₃).

2. Aluminium by electrolytic reduction (Hall-Heroult process)
Aluminium oxide is converted into molten aluminium by electrolysis:

Dissolution: Al₂O₃ is dissolved in molten cryolite (Na₃AlF₆) to lower its melting point (about 950°C).

Electrolysis: Direct current decomposes aluminium into aluminium (cathode) and oxygen (anode, which reacts with carbon to form carbon dioxide).

Casting: The molten aluminium is tapped and cast into ingots or sheets for further processing.

3. Rolling of ingots into foil
Rolling of ingots into foil thickness (0.006-0.2 mm):

Hot rolling: The ingots are heated and rolled into thick plates (approximately 2-6 mm).

Cold rolling: The aluminum sheets are further thinned by continuous rolling and intermediate annealing (heat treatment) is performed to restore ductility.

Finishing: The foils are trimmed, coated (if necessary), and inspected for defects before packaging.

Mengjiang Group has been specialized in the production of aluminum foil for 17 years, from alumina mining to aluminum ingot production to aluminum foil and other deep-processed products. If you need aluminum foil, please feel free to contact us.