Aluminum is used all over the world as a building and structural component in a wide range of applications. One of the reasons that aluminum is so popular is its ability to be endlessly recycled, which makes it a good option in sustainable or green buildings for all types of industries.
Smelting aluminum is a relatively simple process, and it can be done on an industrial scale. To complete the process, large structural blocks made of carbon are used to create sidewalls for the lining of the furnaces. These sidewall carbon blocks are essential to the efficiency of the furnace.
In the smelting process, carbon blocks can also be used as anodes. These blocks are placed in a specialized bath that contains alumina. Then, with the introduction of the electric current, molten aluminum is produced that can be cast into various components, shapes, and sizes.
Cathode Blocks
The carbon blocks that function as the cathode are a mixture of recycled anodes, petroleum coke and a liquid pitch to hold the material together. These are in large brick-like forms that can weigh over a ton. They are produced by baking the bricks for 18 days to cause the blocks to become conductive. Typically, they are placed over layers of insulating bricks and refractory bricks that are designed to insulate the bath and to prevent heat loss.
Sidewall Blocks
The other type of block made of carbon used in the process is used to line the sides of the pot shell or the outer steel layer of the vessel that will be used to melt the aluminum. These are also made with combinations of materials, largely pitch, and ground carbon.
There are also some blocks made of carbon that will function as the anode. These will have a rod, made of aluminum or sometimes copper and stubs, which are made of iron. These anodes will be consumed in the process and have to be replaced regularly to keep the chemical reactions going.