Iron ore pellet production is a process that transforms fine iron ore concentrate into pellets, which are small, spherical balls used as feedstock in blast furnaces or direct reduction plants for steelmaking. The process enhances the handling and metallurgical properties of iron ore, making it more efficient for transportation and steel production.
Key Steps in Iron Ore Pellet Production:
1. Ore Preparation:
– Crushing & Grinding: Raw iron ore is crushed and ground into a fine powder to liberate iron-bearing minerals from gangue (waste material).
– Beneficiation: Low-grade ore is upgraded through processes like magnetic separation, flotation, or gravity separation to increase iron content (typically to 65-72% Fe).
2. Mixing & Binder Addition:
– The fine iron ore concentrate is mixed with binders (such as bentonite clay) and additives (like limestone or dolomite as flux) to improve pellet strength and metallurgical properties.
– Water is added to form a moist mixture suitable for pelletization.
3. Pelletizing (Ball Formation):
– The mixture is fed into a pelletizing disc or drum, where it rolls into small green pellets (9-16 mm in diameter).
– The tumbling action helps form spherical pellets due to surface tension and binding agents.
4. Drying & Preheating:
– Green pellets are dried at ~100–200°C to remove moisture.
– They are then preheated at ~900–1100°C to strengthen them before induration.
5. Induration (Hardening):
– Pellets are fired in an induration furnace (typically a grate-kiln or straight grate system) at ~1200–1350°C.
– This process sinters the particles, forming strong hematite (Fe₂O₃) or magnetite (Fe₃O₄) pellets with high mechanical strength.
6. Cooling & Screening:
– Hot pellets are cooled in a cooler to ~100°C.
– Oversized or undersized pellets are screened out and recycled.
7. Storage & Shipping:
– Finished pellets are stored and transported to steel plants for use.jpg)
blast furnaces or direct reduction processes (e.g., DRI/HBI production).
Types of Iron Ore Pellets:
– Acid Pellets