Use of Char in a Blast Furnace: A Sustainable Alternative to Coal

The blast furnace is a key component in the production of iron and steel and has been used for centuries. In this process, iron ore, coke, and flux are fed into the top of the furnace, where they are then heated and melted to produce molten iron. This molten iron is then refined and processed to produce the high-quality steel that is used in a wide range of applications.

The Importance of Carbon in Steelmaking

Carbon is a critical element in the production of steel and is typically supplied in the form of coke, which is produced by heating coal to a high temperature in the absence of air. This process reduces the impurities in the coal and leaves behind a solid carbon material that is then used as a fuel and reducing agent in the blast furnace.

The use char in a blast furnace instead of coal

While the traditional method of using coal-derived coke in a blast furnace has been effective, there are several advantages to using char as an alternative. Firstly, char is produced through a process known as pyrolysis, which involves heating organic materials in the absence of oxygen. This process results in a highly porous, carbon-rich material that can be used as a fuel and reducing agent in the blast furnace.

One of the biggest advantages of using char in a blast furnace is that it is considered to be a carbon-negative material. This means that when it is used as a fuel and reducing agent in the blast furnace, it actually removes carbon from the atmosphere, rather than adding to it. This is because the carbon in the char was originally absorbed from the atmosphere by the organic material that was used to produce it, and is then being re-released back into the atmosphere when it is burned as fuel.

Another advantage of using char in a blast furnace is that it can be more cost-effective than traditional coal-derived coke. This is because char can be produced from a wide range of organic materials, including agricultural waste and forestry residues, which are often cheaper than coal. Additionally, the pyrolysis process used to produce char is more energy-efficient than the process used to produce coke, which means that less energy is required to produce a given amount of char.

Finally, using char in a blast furnace also has the potential to reduce the environmental impact of the steelmaking process. This is because the pyrolysis process used to produce char captures and locks away carbon dioxide, reducing the overall carbon footprint of the steelmaking process.

Size of the Steel Industry Using the Blast Furnace Method

Despite the advances in steelmaking technology and the increasing use of alternative methods, such as electric arc furnaces, the blast furnace process is still widely used in the steel industry. In fact, it is estimated that more than 70% of the world’s steel is still produced using this method.


In conclusion, the use of char in a blast furnace as a replacement for traditional coal-derived coke has the potential to offer significant benefits to the steel industry, including reduced carbon emissions, cost savings, and improved energy efficiency. This is why more and more steel companies are beginning to explore the use of char as a replacement for traditional coal-derived coke in their blast furnaces.