Iron ore mining, crushing, and processing involve several key steps to extract usable iron from natural deposits. Here’s a detailed breakdown of the process:
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1. Iron Ore Mining
Iron ore is typically extracted through open-pit or underground mining, depending on the depth and geology of the deposit.
– Open-pit mining: Used for shallow, large deposits (e.g., hematite in Australia or Brazil).
– Overburden (waste rock) is removed.
– Ore is drilled, blasted, and loaded onto haul trucks for transport.
– Underground mining: Used for deeper, high-grade deposits (e.g., magnetite in Sweden).
– Shafts and tunnels are dug to access the ore.
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2. Crushing & Screening
After extraction, raw iron ore undergoes size reduction to prepare it for beneficiation.
– Primary Crushing: Large chunks (up to 1.5m) are reduced to ~20–30cm using jaw or gyratory crushers.
– Secondary/Tertiary Crushing: Cone or impact crushers further reduce ore to <10mm.
– Screening: Ore is separated into size fractions (e.g., lump vs. fines) via vibrating screens.
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3. Processing (Beneficiation)
Low-grade iron ore (<60% Fe) requires beneficiation to increase iron content and remove impurities (silica, alumina, phosphorus).
# Common Methods:
1. Gravity Separation
– Used for coarse ore (e.g., hematite).
– Spiral concentrators or jigs separate denser iron particles from gangue.
2. Magnetic Separation
– Applied to magnetite ores (~72% Fe).
– Low-intensity magnets remove waste; high-intensity magnets refine concentrate.
3. Flotation
– For fine particles; chemicals selectively bind iron minerals for separation.
4. Dense Media Separation (DMS)
– Uses a ferro-silicon slurry to separate ore by density.
5. Agglomeration (for fines):
– Sintering: Fines are heated to form clumps for blast furnaces.
– Pelletizing: Fines are rolled
to pellets with binders and hardened in kilns (~65% Fe).
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4. Final Product
Processed
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