Carbon Raiser: The Key to Improve the Steel Production Efficiency

  • High fixed carbon content
  • Low sulfur, phosphorus, nitrogen contents and low impurity content.
  • Dry and medium-sized particles.
Carbon raisers in different particle sizes

Carbon raiser, also known as carbon additive or recarburizer, is a material added to molten metal to increase its carbon content. When being used in steelmaking or casting, the fixed carbon of carbon raiser can reach more than 95%. It has been widely used in various industries such as metallurgy, chemical, and power.

There are many kinds of raw materials and production processes for carbon raisers, including wood-based carbon, coal-based carbon, coke-based carbon, graphite-based carbon, with many sub-categories under each category. High quality carbon raisers generally refer to graphitized carbon additives. As the carbon atoms are arranged in a graphite-like microstructure under high temperature conditions, so it is called as graphitization. Graphitization can reduce the content of impurities in the carbon additive, increase the carbon content, and lower the sulfur content. When being used in casting, carbon raisers can significantly increase the amount of scrap steel used, reduce the amount of pig iron used, or eliminate the need for pig iron.

A bowl of small size carbon raisers

0–2 mm

A bowl of medium size carbon raisers

2–5 mm

A bowl of large size carbon raisers

2–8 mm

A bowl of large size carbon raiser

8–25 mm


Carbon raisers are generally divided into carbon raisers for steelmaking and carbon raisers for casting. Some other additives also need carbon additives, such as for brake pad additives and being used as friction materials. Carbon raisers are external carbon sources for steelmaking and ironmaking. High quality carbon raisers are essential auxiliary additives for producing high quality steel.

Carbon raisers are generally divided into calcined petroleum coke (CPC), graphitized petroleum coke (GPC), calcined anthracite coal (CAC), electrically calcined anthracite, graphite electrode scraps, and graphite column carburizer. They are usually used for converter smelting or high-carbon steel smelting. The requirements for carbon raisers used in top-blown converter steelmaking are high fixed carbon content, low ash content, low volatile, low sulfur content, low phosphorus content, low nitrogen content and low other impurities. Besides, the carbon raisers also are required to be dry, clean, and in moderate particle size.

Graphitized Petroleum Coke (GPC)

It is a high purity carbon material made from high quality petroleum coke at a temperature of 2500–3500 °C. It features high fixed carbon content, low sulfur, low ash content, and low porosity, making it an ideal carbon raiser for producing high quality steel, cast iron, and alloys. It can also be used as an additive for plastics and rubber.

Calcined Petroleum Coke (CPC)

It is made from raw petroleum coke (RPC) by high temperature pyrolysis process in a forging furnace above 1500 °C. During the calcination process, the moisture and volatile organic compounds in the raw coke can be removed, thereby improving the purity and density of the coke. CPC has a high carbon content, low ash content, and high electrical and thermal conductivity, and is widely used in the aluminum industry for the melting of alumina. It is also used as a carbon raiser in foundries for producing high-carbon steel.

Calcined Anthracite Coal (CAC)

It is a kind of heat-treated anthracite coal, featuring low phosphorus content, low ash content, and low sulfur content. CAC is typically classified into two categories, one is gas calcined anthracite (GCA) that is widely used as a carbon raiser in the steelmaking and casting industries. The other is electrically calcined anthracite (ECA) that is used in the metallurgical industry for producing carbon blocks, cathode carbon blocks, carbon bricks, and carbon paste.

Electrically Calcined Anthracite (ECA)

It is not anthracite coal that has been calcined in a gas furnace, but rather a semi-graphitized product obtained by heating high-quality anthracite coal to temperatures up to 2000 °C in a DC electric calcination furnace to remove volatile matter. ECA has a higher carbon content and a relatively higher thermal and electrical conductivity than traditional anthracite, and has excellent performance in terms of mechanical/compressive strength and long-term stability. It is mainly used in the manufacture of electrode paste, as well as in the production of steel and aluminum.

Gas Calcined Anthracite (GCA)

It is produced by annealing anthracite in a horizontal gas furnace at about 1280 °C. It is made from anthracite and is known for its low ash content, low sulfur content and low volatile content. It is mainly used as a carbon raiser in the steel or foundry industry.

Graphite Electrode Scraps

It is also known as electrode scrap or graphite scrap, and is a collective term for the waste products produced by carbon products after graphitization and the materials generated by cutting and rushing graphitized products during processing. It is manually cleaned, rushed, and screened and features high carbon content, low sulfur content, low nitrogen content, low resistivity and low ash content, etc. It is the carbon raiser used in steel making and casting industries.

Graphite Column Carburizer

Graphite column carburizer is a kind of column carbon raiser made of graphite powder and binder. It features high carbon content, low impurity content, high absorption rate and good use effect. It can improve the absorption rate of molten iron to the carbon raiser, shorten the absorption time, enhance the scrap steel output and reduce the production cost, thus realizing the reuse of scrap steel.

Table 1: Specifications of Various Carbon Raisers
Item GPC (Graphitized Petroleum Coke) Semi-GPC CPC (Calcined Petroleum Coke) GCA (Gas Calcined Anthracite) GCA (Gas Calcined Anthracite) GCA (Gas Calcined Anthracite) Graphite Electrode Scraps
Fixed Carbon ≥ 98.5% ≥ 98.5% ≥ 98.5% ≥ 90% ≥ 92% ≥ 95% ≥ 98.5%
Sulfur Content ≤ 0.05% ≤ 0.30% ≤ 0.50% ≤ 0.50% ≤ 0.40% ≤ 0.25% ≤ 0.05%
Volatile Matter ≤ 1.0% ≤ 1.0% ≤ 1.0% ≤ 1.5% ≤ 1.5% ≤ 1.2% ≤ 0.8%
Ash ≤ 1.0% ≤ 1.0% ≤ 1.0% ≤ 8.5% ≤ 7.5% ≤ 4.0% ≤ 0.7%
Moisture Content ≤ 0.5% ≤ 0.5% ≤ 0.5% ≤ 1.0% ≤ 1.0% ≤ 1.0% ≤ 0.5%
Particle Size/mm 0–1; 1–3; 1–5; etc. 0–1; 1–3; 1–5; etc 0–1; 1–3; 1–5; etc 0–1; 1–3; 1–5; etc 0–1; 1–3; 1–5; etc 0–1; 1–3; 1–5; etc 0–1; 1–3; 1–5; etc
  • 1 MPa = 10.2 kgf/cm2; 1 W/m.k = 0.86 kcal/cm.h.°C
  • These properties are typical values and not guaranteed.