At SINOMENCO Industrial Material Co., Ltd., we are dedicated to supplying top-tier carbon materials to meet the diverse needs of industries worldwide. We offer calcined petroleum coke, a crucial ingredient for aluminum production and steel manufacturing. Additionally, we provide graphite electrodes from KFCC, renowned for their exceptional electrical conductivity and thermal resistance, which are indispensable in electric arc furnaces. Our commitment to excellence ensures that we deliver products that not only meet but also exceed the expectations of our valued clients.
Carbon Products (CPC, GE)
A graphite electrode is a high-temperature resistant, conductive material made from graphite. It’s primarily used in electric arc furnaces for steelmaking, as well as in other applications like smelting ferrous alloys and electric discharge machining. Graphite electrodes are created from petroleum coke and pitch coke as aggregate, with coal tar pitch as a binder. They are then extruded and shaped, followed by baking to carbonize the binder. Graphite’s structure, with layers of carbon atoms arranged in hexagonal patterns, allows electrons to move freely, making it an excellent conductor of electricity. This unique property, along with its chemical stability and ability to withstand high temperatures, makes graphite an ideal material for electrodes in various industrial processes.
Creating graphite electrodes involves a sophisticated manufacturing process that combines both chemical and physical procedures to transform carbon-based materials into electrodes capable of conducting electricity. Here’s a detailed look at the process:
Raw Material Selection
Graphite electrodes are typically made from petroleum coke, a carbon-rich solid derived from oil refining. The quality of the petroleum coke directly affects the quality of the graphite electrodes.
Pulverization and Mixing
The petroleum coke is pulverized into a fine powder and then mixed with a pitch binder, which acts as a glue to hold the coke particles together. This mixture is often kneaded to ensure uniformity.
Extrusion
The kneaded mixture is then extruded into the shape of rods. This is done by pressing the mixture through a die under high pressure. The size of the die determines the diameter of the electrodes.
Baking
After extrusion, the rods are baked at a temperature of around 800-1,200°C. This step is crucial as it carbonizes the pitch binder and releases volatile substances, resulting in a solid but porous structure.
Impregnation
To increase the density and electrical conductivity of the electrodes, they undergo an impregnation process. They are soaked in a liquid pitch, which fills the pores created during the baking process.
Re-baking
The impregnated electrodes are baked again at a higher temperature, usually above 2,500°C. This step graphitizes the carbon, giving the electrodes their final structure and properties.
Machining
Once cooled, the electrodes are machined to the required dimensions and tolerances. Threads are also added to the ends of the electrodes so they can be joined together.
Quality Control
Throughout the manufacturing process, quality control measures are in place to ensure the electrodes meet specific standards. This includes testing for electrical resistance, strength, and density.
Final Product
The finished graphite electrodes are then ready for use in various applications, such as electric arc furnaces for steel production, where they conduct electricity to generate the heat needed to melt scrap steel
The process of making graphite electrodes is complex and requires precise control at every stage to ensure the final product meets the necessary specifications for its intended use. The high temperatures involved in the baking and re-baking stages are particularly critical, as they induce the structural changes in the carbon that give graphite its unique properties.
Graphite electrodes have a wide range of applications due to their excellent electrical conductivity, mechanical stability, and resistance to high temperatures. Here are some of the key applications:
Electric Arc Furnaces (EAF)
The primary use of graphite electrodes is in EAF for steel production. They conduct electrical energy into the furnace, which generates the heat needed to melt scrap steel and other materials.
Ladle Furnaces
Similar to EAF, graphite electrodes are used in ladle furnaces to refine steel by maintaining the temperature and adding alloying elements.
Electrolytic Cells
In the production of aluminum and other metals, graphite electrodes serve as anodes in electrolytic cells, where they facilitate the electrochemical reactions necessary for metal extraction.
Electroanalysis and Sensors
Graphite electrodes are used in electroanalysis to measure the concentration of various chemicals in a solution. They are also integral to the design of biosensors and chemical sensors due to their ability to be easily modified to enhance selectivity.
Energy Storage
Graphite electrodes are utilized in batteries and fuel cells as they can efficiently conduct electricity and withstand the chemical reactions occurring within these devices²[2].
Research and Development
In fundamental electrochemistry research, graphite electrodes are a cost effective alternative to other carbon-based electrodes due to their interesting electrochemical properties. These applications showcase the versatility of graphite electrodes and their importance in various industrial and scientific fields.
Graphite electrodes offer several advantages over other electrode materials, such as copper, due to their unique properties and characteristics. Here’s a detailed explanation of the benefits of using graphite electrodes:
High Electrical Conductivity
Graphite is a good conductor of electricity, which makes it suitable for use as an electrode material.
Thermal Stability
Graphite has a high melting point and can withstand high temperatures without degrading, which is beneficial for high-temperature applications.
Mechanical Strength
The mechanical properties of graphite increase with temperature, unlike many other materials.
Low Coefficient of Thermal Expansion (CTE)
Graphite’s low CTE ensures the stability of electrode geometry during thermal cycling.
Ease of Machining
Graphite can be easily machined into various shapes and sizes, which is advantageous for custom electrode designs.
Chemical Inertness
Graphite is chemically stable and has low reactivity, which prevents it from reacting with other substances during use.
Lightweight
Graphite is less dense than metals like copper, making it a lighter option for electrodes.
These properties make graphite electrides particularly useful in applications such as electrochemical cells, batteries, and electrical discharge machining (EDM). The choice between graphite and other materials like copper often depends on specific application requirements and the availability of support equipment on the shop floor.
Calcined Petroleum Coke (CPC) is a high-purity carbon material obtained by calcining petroleum coke. It is produced by heating raw petroleum coke (also known as green coke) to remove volatile hydrocarbons and impurities. CPC plays a crucial role in various industries, particularly in aluminum smelting and steel production. It serves as a valuable raw material for making carbon anodes used in aluminum electrolysis cells and other applications
Aluminum Production
CPC is primarily used in the production of anodes for the aluminum smelting process. It’s a critical component due to its high carbon content and electrical conductivity. The anodes made from CPC are used in the Hall-Héroult process, which is the primary method of aluminum production. The quality of CPC directly affects the efficiency and cost of aluminum production.
Steel Manufacturing
As a carbon raiser, CPC is utilized in steel manufacturing to adjust the carbon content of the steel. It’s added during the steel-making process to achieve the desired carbon level, which is essential for controlling the mechanical properties of steel.
Graphite Electrode Production
CPC is also used to produce graphite electrodes, which are necessary for electric arc furnaces in steel production. These electrodes are used to melt scrap steel, and the quality of CPC impacts the performance and lifespan of the electrodes.
Titanium Dioxide Production
CPC serves as a reducing agent in the production of titanium dioxide, a pigment used in paint, plastics, and paper. The process involves the carbothermic reduction of titanium dioxide, where CPC’s purity is a significant factor.
Other Carbon-Consuming Industries
CPC finds applications in various other industries that consume carbon, such as the production of synthetic graphite, lithium-ion battery anodes, and as a conductive backfill in ground electrode stations.
As a Fuel
While not as common, CPC can be used as a fuel in power generation, cement kilns, and other industries due to its high carbon content. However, this usage is limited due to environmental concerns related to its higher carbon dioxide emissions compared to other fuels. In summary, calcined petroleum coke’s versatility and essential role in key industrial processes make it a valuable commodity in the global market. Its properties of being chemically inert, physically stable, and having a high carbon content ensure its continued demand across various sectors.