How is aluminum extracted from bauxite?
Bauxite is refined into alumina (Al₂O₃) using the Bayer process. Alumina is then smelted via electrolysis in Hall-Héroult cells. This requires cryolite as a flux and massive electricity. Modern smelters use renewable energy. It takes 4-5 tons of bauxite to make 1 ton of aluminum.
What are the main aluminum alloy series?
Series 1xxx is 99% pure aluminum. 3xxx contains manganese for workability. 5xxx with magnesium resists seawater. 6xxx (magnesium + silicon) is ideal for extrusion. 7xxx with zinc creates ultra-strong aerospace alloys.
How does aluminum recycling work?
Scrap is sorted by alloy type and cleaned. It's melted in furnaces at 750°C. Fluxes remove impurities before casting. Recycled aluminum is identical to primary metal. A soda can be recycled infinitely into new cans.
What's the difference between wrought and cast aluminum?
Wrought alloys are mechanically worked (rolled/extruded). Cast alloys have higher silicon content for fluidity. Wrought products have better mechanical properties. Casting allows complex geometries. Bicycle frames use wrought; engine blocks use cast.
Why is aluminum foil shiny on one side?
During rolling, two foil layers pass through mills simultaneously. The side touching polished rollers becomes shiny. The matte side results from contact with another foil layer. Both sides have identical properties. Thickness can be as low as 0.006mm.
