Graphite and carbon are two popular materials used for making electrodes. Both are good conductors of electricity. Nevertheless, their properties, service life, applications, and production processes are diverse.
This graphite electrode vs. carbon electrode post makes an in-depth comparison of these electrodes. It aims to provide a clear understanding of them.
Graphite Electrode vs. Carbon Electrode: Comparison of Different Factors
Definition
A graphite electrode is a cylindrically-structured conductive component. It is used in electric arc furnaces to smelt steel, smelt metals or metal alloys.
The electrode consists of fine-quality petroleum needle coke and binding agents.
Generally, it comes in three types: Regular Graphite Electrode, High Power Graphite Electrode, and Ultra High Power Graphite Electrode.
The carbon electrode comprises calcined anthracite coal, petroleum coke, graphite, and other raw materials.
A carbon electrode is used in electric arc furnaces to smelt silicon, ferroalloys, yellow phosphorus, calcium carbide, corundum, and more.
Production Process
Graphite Electrode
The production of graphite electrodes involves various steps. It starts by collecting raw materials like petroleum needle coke and asphalt.
These raw materials are crushed and sent for screening. In the next step, they are mixed to achieve a paste-like consistency.
Engineers mold this paste into cylindrical electrodes by using an extrusion press. The process helps electrodes retain their structure.
Next, they bake molded electrodes at a high temperature. The temperature can be as high as 1000 °C. The baking is followed by the pitch impregnation process.
In an autoclave, an impregnate penetrates the pores of electrodes under certain pressure and temperature.
The process improves the strength and electrical resistance of the electrodes.
Graphitization is the second baking process that converts electrodes into graphite carbon electrodes. The temperature goes up to 3000°C for this process.
At last, manufacturers process electrodes to achieve specific dimensions.
Carbon Electrode
The carbon electrode production follows similar steps. First, makers collect raw materials like calcined anthracite coal, petroleum coke, and graphite. They crush these materials to make a fine powder.
After that, the powder is mixed with a binder (coal tar pitch) to create a fine mixture. The mixing process binds all the carbon particles together.
In the next step, this mixture is shaped into electrodes using extrusion. After that, makers bake them at temperatures, ranging between 1000°C and 1200°C. The baking makes electrodes hard.
If electrodes have some pores, engineers fill them with a binding material. They do this impregnation in an autoclave.
Like graphite electrodes, these electrodes also undergo a graphitization process. It involves re-baking at a high temperature (about 3000°C).
At last, makers shape them to achieve specific dimensions depending on their applications.
Physical & Chemical Properties
Graphite Electrode
- Graphite electrodes are primarily made of natural or synthetic graphite.
- Graphite is an excellent conductor of electricity due to its delocalized electrons that move freely.
- Graphite electrodes offer high thermal conductivity because of their crystalline structure. It can quickly disperse heat during high-temperature applications.
- Graphite electrodes have high chemical inertness. They can endure all types of chemicals due to their resistance against oxidation and corrosion.
- The carbon atoms of graphite make a strong covalent bond. Therefore, graphite electrodes have a high melting point (around 3600 °C).
Carbon Electrode
- Carbon electrodes comprise amorphous carbon or mixed carbon materials.
- Carbon electrodes come with moderate electrical conductivity.
- These electrodes have decent thermal stability. However, it is lower than that of graphite.
- Like graphite, carbon is also chemically inert. It does not degrade by electrochemical reactions.
Applications
Graphite Electrode
- Graphite electrodes are primary components of EAFs (Electric Arc Furnace). Various industries use this furnace for steelmaking and melting scrap metal.
- Refining ladle furnaces also use graphite electrodes for secondary steel refining.
- Submerged arc furnaces also employ graphite electrodes to produce ferroalloys.
- You can also use these electrodes in resistance furnaces to produce glass, silicon, and carbide.
Carbon Electrode
- Carbon electrodes are used for conductive electrodes in ore-fired furnaces to smelt yellow phosphorus, silicon, ferroalloys, etc.
- Carbon electrodes have a primary role in electrolysis processes for chlorine production.
- Battery manufacturing companies use these electrodes as anode material in various batteries.
- Carbon electrodes produce high heat when an electric current passes through them. As a result, individuals use them in various resistance heating applications.
Production Cost
The production cost of graphite and carbon electrodes varies depending on various factors. These can be the current price of raw materials, energy cost, quality/grade of electrodes, and manufacturing complexity.
Graphite Electrode
Usually, graphite electrode production costs are higher than those of carbon electrodes. Raw materials like needle coke are expensive. Besides this, the overall production of graphite electrodes is complex.
Carbon Electrode
It is comparatively cheaper to produce carbon electrodes. Its production process does not require graphitization, has low production costs and high economic benefits.
Service Life
The service life of electrodes depends on various factors. These include the quality of raw materials, electrode handling, operation, design, and current intensity of electric arc furnaces.
Graphite Electrode
In practical applications, the average service life of graphite electrodes is between 50-80 smelting times, and generally needs to be replaced. For large smelting equipment such as blast furnaces, the average service life can reach more than 100 times.
Carbon Electrode
Carbon electrodes have a relatively shorter service life. Their low strength and vulnerability to oxidation make them unsuitable for demanding applications.
Conclusion
Carbon electrodes and graphite electrodes have many differences but also have similar characteristics. Understanding their performance and application can make better use of them and improve the efficiency of your industrial production. If you’d like to know more, you can contact Jinsun today.
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