TECHNOLOGY & PRODUCTS
MIDREX Process
The world's leading direct reduction technology
A proven ironmaking process
For over half a century Midrex has delivered the most trusted, reliable and widely adopted direct reduction technology in the world.
With nearly 100 modules built across five continents, the The MIDREX™ Process accounts for approximately 78 percent of cumulative shaft furnace DRI production worldwide.
How the MIDREX Process works
The MIDREX Process is a gas-based direct reduction ironmaking process available in multiple configurations that converts iron ore into direct reduced iron through an integrated system of reduction gas generation, a shaft furnace, and heat recovery.
Designed for long-term, continuous operation and supports multiple product forms. It can be designed to switch from one DRI form to another with no disruption, including cold DRI (CDRI), hot DRI (HDRI) and HBI, to meet different steelmaking and logistics requirements.
The MIDREX Process
The MIDREX Process converts iron ore into direct reduced iron through a continuous, gas-based reduction process. Iron oxide pellets or lump ore are fed into a vertical shaft furnace, where they are exposed to a controlled flow of hot reducing gas.
As the ore descends through the furnace, oxygen is removed from the iron oxide, producing metallic iron while maintaining structural integrity and consistent quality. The integrated design of the process allows material and energy flows to be managed efficiently, supporting stable operations on a large scale.
This system-based approach enables the MIDREX Process to deliver reliable performance across a wide range of operating conditions.
Key elements of the MIDREX Process
Reduction gas generation and reforming
The reducing gas used in the MIDREX Process is primarily hydrogen and carbon monoxide. It is generated through reforming of natural gas or other suitable feedstocks, while top gas from the shaft furnace is recycled within the process to improve energy efficiency and maintain reducing conditions. By integrating reforming and gas recycling within the process, the MIDREX Process efficiently reuses energy while maintaining the reducing conditions required for iron ore reduction. The process architecture also allows flexibility in the composition of the reducing gas, supporting operation with hydrogen-rich gas streams as energy systems evolve.
This integrated gas loop is a core element of the MIDREX Process.
Iron ore reduction in the shaft furnace
At the heart of the MIDREX Process is the shaft furnace, where iron ore is reduced in a countercurrent flow arrangement. Iron ore moves downward through the furnace by gravity, while hot reducing gas flows upward in the opposite direction. This countercurrent design promotes efficient heat and mass transfer, enabling controlled removal of oxygen from the iron oxide. The result is direct reduced iron with predictable metallization and carbon levels, suitable for a range of downstream steelmaking applications. Careful control of process conditions supports consistent product quality and stable long-term operation.
Product forms and discharge options
The MIDREX Process supports the production of direct reduced iron in multiple forms to suit different steelmaking routes and logistics requirements. These include cold direct reduced iron (CDRI), hot direct reduced iron (HDRI), and hot briquetted iron (HBI). The ability to produce and switch between product forms allows steel producers to align iron unit supply with melt shop configurations, transport constraints, and market strategies. This flexibility is an inherent feature of the process design rather than an add-on. Product options are selected based on operational and commercial needs.