A dry screening plant for iron ore is used to classify and separate iron ore particles by size without the use of water. This method is cost-effective, environmentally friendly (as it reduces water consumption), and suitable for arid regions. Below are key aspects of dry screening in iron ore processing:
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1. Purpose of Dry Screening in Iron Ore Processing
– Size Classification: Separates iron ore into different size fractions (e.g., lump, fines, pellets feed).
– Pre-Concentration: Removes low-grade or waste material before further processing.
– Dust Control: Helps manage dust emissions compared to wet screening.
2. Key Components of a Dry Screening Plant
– Vibrating Screens (Most common type for dry screening)
– *Linear Motion Screens* – For fine and sticky ores.
– *Circular Motion Screens* – For coarser material.
– Grizzly Screens – For scalping oversized rocks before crushing.
– Air Separation & Dust Extraction Systems – To reduce airborne dust.
– Feed Hoppers & Conveyors – For material handling.
3. Advantages of Dry Screening
– No water usage (beneficial in dry regions).
– Lower operational costs (no slurry handling or dewatering needed).
– Faster processing compared to wet screening.
– Reduced environmental impact (no tailings ponds).
4. Challenges & Solutions
– Dust Generation → Solved by using dust suppression systems (mist sprays, enclosures, bag filters).
– Blinding & Clogging → Solved by using screen cleaners (ball decks, brush systems) or adjusting screen angles.
– Moisture Sensitivity → Works best with ores containing <5% moisture; otherwise, pre-drying may be needed.
5. Applications in Iron Ore Processing
– Pre-screening before crushing.
– Separation of lump ore (+6mm to 30mm) from fines (<6mm).
– Removal of contaminants before beneficiation.
– Final product classification for direct shipping ore (DSO).
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6. Example Flow Sheet for Dry Screening Plant
1. ROM (Run-of-Mine) Ore → Grizzly Screen → Oversize to Crusher
2. Crushed Ore → Vibrating Screen → Lump (+6mm) & Fines (-6mm)
3. Fines