Posts in category: Steel

What It Is:

• Porous iron (90–94% Fe) produced by chemically reducing pellets or lumps without melting, using natural gas or coal.

Forms:

• DRI: Lumpy or powdery form, prone to rusting.

• HBI (Hot Briquetted Iron): Compressed DRI for safer transport.

How It’s Produced:

1. Reduction:

   • Gas-based (MIDREX®/HYL): Pellets reduced using syngas (H₂ + CO) at 800–1,050°C.

   • Coal-based (Rotary Kiln): Common in India and China, using coal as the reductant.

2. Cooling:

   • The reduced iron is cooled to prevent re-oxidation.

Applications:

• Electric Arc Furnaces (EAFs): DRI mixed with scrap to produce high-purity steel with low copper and other residuals.

• Alternative to scrap: Especially important in regions with limited scrap supply, such as the Middle East.

• Green steel: Has future potential through hydrogen-based DRI (e.g., HYBRIT project).

Top Producers:

• Gas-based: Iran, Saudi Arabia, USA (using MIDREX plants).

• Coal-based: India (the world’s largest DRI producer).

Comparative Summary

What It Is:

• Uniform, hardened spheres (6–16 mm diameter) made from concentrate and binders (e.g., bentonite), fired at 1,200–1,300°C to achieve high strength.

• Iron content: 65–72% Fe.

How It’s Produced:

1. Mixing:

   • Concentrate and binder are mixed and rolled into green pellets.

2. Induration:

   • Drying: Heated to around 300°C to remove moisture.

   • Firing: Heated to about 1,300°C to harden the pellets by oxidizing magnetite to hematite.

   • Cooling: Air-cooled for safe storage and shipping.

Applications:

• Blast Furnaces (BF): Preferred for high efficiency due to low slag formation and uniform size.

• Direct Reduction (DRI): Used with natural gas to produce sponge iron (DRI).

• Shipping: Pellets are dust-free and dense, which lowers freight costs.

Market Insight:

• Premium product: Pellets trade at approximately 30% higher prices than concentrate.

• Top exporters: Brazil, Sweden, and Canada.

What It Is:

• A high-grade iron ore powder (60–70% Fe) obtained by removing impurities such as silica and alumina from low-grade ore through crushing, grinding, and beneficiation processes like magnetic separation or flotation.

• Appearance: Fine, dark-gray powder.

How It’s Produced:

1. Mining:

   • Extracted from open-pit or underground mines.

2. Beneficiation:

   • Crushed ore is mixed with water, and magnetic separators remove impurities like silica.

   • The result is filtered and dried into concentrate powder.

3. Pelletizing (Optional):

   • The concentrate can optionally be processed further into pellets.

Applications:

• Primary use: As feedstock for iron pellet production.

• Blast Furnaces (BF): Often mixed with pellets and coke to produce pig iron.

• Direct Shipping Ore (DSO): Some high-grade concentrates are exported directly, such as from Brazil to China.

Key Producers:

• Vale (Brazil), Rio Tinto (Australia), Metinvest (Ukraine).