Bechtel is a global leader in designing and building production facilities for aluminum—one of the most important metals in the modern world. Strong and light, it is used in thousands of different products from automobiles to soft-drink cans.
Most aluminum is produced using the Hall-Héroult process, developed simultaneously by American Charles Hall and Frenchman Paul Héroult working independently of each other in the late 1800s. Hall went on to found the company that would become the Aluminum Company of America, now known as Alcoa.
Aluminum is derived from bauxite ore that has been refined into alumina. In an aluminum smelter, alumina is dissolved in an electrolytic bath of molten cryolite (sodium aluminum fluoride) inside a large pot. An electric current is passed between carbon anode rods (positively charged electrodes) made of petroleum coke and pitch, and a negative cathode of carbon or graphite that lines the bottom of the pot.
The electrolysis produces molten aluminum, which is transferred to very large cast-iron crucibles that are then transported to the casthouse, where the aluminum is formed into ingots, bars, or other shapes for customers.
