Graphite is used in a wide range of different industries. Blocks of this material can be used as sidewall blocks in aluminum smelting processes offering durable, reliable sidewalls that are able to stand up to the high temperature of smelting without any loss of strength or structure.
Graphite blocks can be produced in a variety of ways. There are different terms that are used when discussing graphite, which also provides information on the material used in the block as well as how the block itself is processed.
To help to understand the differences, here is a brief summary of different options in graphite blocks that can be used in the smelting process:
* Electro-graphite – this is typically what is meant when the term “graphite” is used. It is produced by heating carbon materials up to 3000 degrees Celsius to cause a change in the structure of the carbon. This change in the crystallographic structure then also changes the chemical and physical aspects of the material as well as the binder used with the original carbon. This process is known as graphitization.
* Semi-graphite – this is a mixture of particles of graphite with a binder that can be pitch or tar. This is baked at a lower temperature of not more than 1400 degrees Celsius. The resulting product has good thermal conductivity but is also porous. Baking the semi-graphite again with silicon is often required for refractory applications.
* Semi-graphitized – this is baked at a lower temperature than graphite, typically at 1600 to 2400 degrees Celsius rather than 2400 to 3000 degrees. This results in a material that only partially changes in structure. This partial change increases the refractory ability while also making these types of graphite blocks more resistant to oxidation or other types of chemical damage.
To determine the right type of graphite material for blocks for any application, talk to your distributor. Differences in the physical and structural properties will make a big difference in durability and performance.