Why are graphite electrodes used in electrolysis?

Graphite electrodes are an essential electrolysis component due to their superior properties, high thermal and electrical conductivity, low cost, and corrosion resistance. Using graphite electrodes can help improve electrolysis efficiency by providing a more efficient conducting medium than other types of electrodes. This is because they have a higher surface area to volume ratio than other materials and can thus provide better current density at lower voltages. This article explores the benefits of using carbon graphite electrodes in electrolysis. Including their ability to conduct electricity, reduce costs, and increase safety efficiency.

What is electrolysis?

Electrolysis is a process that uses electricity to move electrons in a liquid or solid. In electrolysis, two electrodes (a positive and a negative) are placed into the material being processed. Electric current flows through the material causing chemical reactions and releasing atoms from molecules.

Graphite electrodes are used in electrolysis because they can efficiently conduct electricity and resist corrosion.  Graphite helps separate the processed material’s positively and negatively charged ions.

Benefits of Using Graphite Electrodes for Your Next Electrolysis

Using graphite electrodes for your next electrolysis has several benefits. It helps ensure that the electric current flows efficiently, preventing energy loss and reducing the time to process materials. Carbon graphite also resists corrosion, so it lasts longer than other metals used in electrolysis. The material is lightweight and can be safely stored and reused multiple times.

Finally, since it is an inert material, it will not react with or affect any component a worker is working on. This means workers can produce higher-quality products in less time.

What happens to graphite during electrolysis?

When subjected to electrolysis, graphite is broken down into component atoms, carbon, and hydrogen. The carbon atoms form a thin deposit on the electrode, while the hydrogen atoms are released as gas. The electrolysis end products depend on the graphite’s characteristics, including its origin and the extent of the current applied.

At higher currents, the graphite decomposes into carbon dioxide and water. We call this reaction as electrolysis oxidation. The end products of oxidation depend on the amount of current applied and the oxidation state of the graphite. The oxidation state of the graphite determines the rate at which the reaction proceeds.

Common Applications of  Graphite in Small EAF

Graphite electrodes are used in electrolysis because they can conduct electricity efficiently and resist corrosion. This makes them well-suited for the small electric arc furnaces (EAFs) commonly used for metal production.  Graphite helps create a high-temperature and stable electric arc between two electrodes.

They then made it easier to control the intensity of the heat generated by the furnace.  Graphite’s strength and low electrical resistance make it an ideal material for creating electrodes that can withstand the harsh conditions of these furnaces.

Physical properties of graphite electrodes

Carbon content: about 90%; ash content: about 10%; actual density: 1.9-2.0g/cm3; false density: 1.5-1.6g/cm3; porosity: 20-25%. The maximum diameter can reach 1200mm and above. In the case of the same current passing, the diameter of the carbon graphite electrode should be more prominent. For example, the diameter of the graphitized electrode used in the regular electric arc furnace is 200mm, and the diameter of the carbon graphite electrode must be 300-350mm.

If the diameter is selected too thin, the current density will be higher than the specified standard.  Then will cause the electrode nipple to overheat and cause a fracture, and fall into the furnace. The result is the shutdown of the stove, lower production efficiency, and increased electrode consumption.

What factors when choosing graphite electrodes Products?

• Carbon content: The amount of carbon in the graphite should be considered when selecting carbon graphite as output, as it affects its performance and durability. 
• Ash content: As ash can reduce the efficiency of graphite electrodes, it is essential to consider how much ash is present when choosing the suitable graphite.
• Actual density/false density: It is essential to select the right proper density of graphite for the application, as this will affect its conductivity and heat transfer properties.
•  Porosity: When choosing graphite, consider the porosity level. Because higher porosity may lead to its performance degradation, leading to failure due to poor contact between the electrode and the molten material. 
• Maximum diameter: To ensure efficient current passage and prevent overheating and electrode nipple fracture. Please select the largest diameter of the graphite you intend to use.

In general

You need to consider various factors based on your actual production, choose products with suitable performance and price, and improve your production efficiency, which is also what we expect. To learn more about carbon electrodes, please read our blogs.