Fabricate aluminum is a light silvery metal and is the most common metal in the Earth's crust. However, it's also too reactive to exist in nature as a pure metal under most conditions. Aluminum can be found in relatively pure form in volcanic mud, where the low oxygen content prevents aluminum from oxidizing. However, unlike other metals that may be refined by purely mechanical means, commercial production of aluminum requires the metal to be extracted from its ore electrolytically, a process that uses electricity to separate aluminum from other elements.
1. Refine the aluminum ore. After the ore (usually bauxite) is mined, it's crushed to a fine consistency and mixed with sodium hydroxide (NaOH). This strong base dissolves the nonmetallic substances, which are then skimmed off the ore.
2. Allow the heavier metals to settle to the bottom, and remove them from the solution. The remaining material is now called "slurry." Transfer the slurry to a "digester" tank and add more sodium hydroxide.
3. Heat the slurry to 145 degrees Celsius in the digester tank under 50 atmospheres of pressure for up to several hours. This process produces a solution of sodium aluminate.
4. Perform a series of precipitation processes to allow the sodium aluminate to settle to the bottom of the solution. This results in a highly concentrated solution of sodium aluminate powder. Alumina hydrate is added to this solution, which causes pure alumina (Al2O3) to settle out of the solution.
5. Separate aluminum from oxygen with electrolysis. The alumina is dissolved into an electrolyte solution and placed in a tank with two carbon electrodes. When the current is turned on, the negative electrode adds electrons to the alumina, which causes the aluminum to separate from the oxygen. The pure metal then sinks to the bottom of the tank, where it can be collected.
Related Post: How to Fix Baseboard Molding