The HBI direct reduction process 2 minutes spent reading

The HBI direct reduction process

Viktoria Steiniger (Maternity Leave)
Holds editorial responsibility for blog topics, is researching and writing articles. Her stories give insights into the world of the voestalpine Group.

As voestalpine, we plan to gradually switch from the coal-based blast furnace route to a green power-based electric steel route starting in 2027. This is made possible by a fundamental technological innovation. In addition to scrap and liquid pig iron, HBI is used, which is produced in the so-called direct reduction process.

HBIHBI stands for hot briquetted iron – porous sponge iron, pressed into briquettes. HBI is created by reducing the iron ore with natural gas. HBI can be used as a pre-material in blast furnaces or electric arc furnaces.

In blast furnaces, HBI replaces coke and iron ore, while in electric arc furnaces it replaces scrap metal.

The direct reduction process

HBI is the product of reducing iron ore with natural gas. This is called the direct reduction process and is an environmentally-friendly production process; a DRI plant uses natural gas which is more environmentally sound than coke. The reduction process takes place in the reduction tower.  A tower is the heart of the plant. The direct reduction process is a complex process, which, explained in simple terms, consists of the following steps:

  • Raw material iron ore pellets:
    Iron ore pellets – the raw material – are fed into the reactor
  • Natural gas is converted into reducing gas:
    Natural gas is converted into reducing gas and then injected
    Reducing gas circulates in a closed system and is recycled
  • The direct reduction process:
    Hot reducing gas flows through the iron ore, from the bottom to the top, according to the counterflow principle
    The Oxygen content is reduced = “sponge iron” is produced
  • “Sponge iron” is pressed into briquettes (Hot Briquetted Iron)

Note: In April 2022, voestalpine sold the majority of the Texas plant to ArcelorMittal

Direct reduction as bridging technology

Direct reduction is considered an important bridging technology for decarbonizing steel production. Starting in 2027, we at voestalpine plan to gradually switch from the coal-based blast furnace route to a greentec-based electric steel route. The aim of greentec steel is to achieve climate-neutral steel production by 2050. Read more on thee greentec steel microsite:


Viktoria Steiniger (Maternity Leave)