In specific industries, there is the need to use quality, customized carbon electrodes. Carbon has long been seen as an ideal material for electrodes for several different reasons.
One of the most important roles of carbon electrodes is to carry a current effectively. This occurs because of the structure of the carbon itself. It allows for three covalent bonds and one free electron, which increases the ability to transfer the current.
The use of carbon electrodes in electrochemical processes is very common. It is a non-metallic substance that can withstand extremely high temperatures in environments. This makes it a top selection for high-temperature arcs and, combined with lower costs, it is a highly efficient option in operations such as smelting or metal refining.
In Smelting
Aluminum is typically processed through the Hall-Heroult process, but there are other processes that can be used as well. With the electrolysis method, the Hall-Heroult process, the aluminum is processed in an electrolysis cell.
This cell consists of a steel shell that is lined with specific material, including graphite, to provide refraction. Within this cell, the process of electrolysis occurs, which is designed to allow the aluminum oxide or alumina to be broken down into aluminum.
Two electrodes are used in the cell that contains the molten alumina. This is done at 1,832 degrees Fahrenheit, which is lower than the actual melting point of alumina. This is accomplished by the addition of cryolite to reduce the required temperature.
A single electrode is used to create an anode, with shell or the vat itself as the other electrode or the cathode. An electrical current is then used, passed through the molten contents of the vat, which causes the transformation for the alumina at the cathode into aluminum metal. This metal then sinks to the bottom and can be collected throughout the process.
The electrodes, made of carbon, are critical for this process. They have to be able to withstand the extremely high heats of this process to maximize the recovery of the aluminum metal.