Flotation cells are essential equipment in ore beneficiation, used to separate valuable minerals from gangue (waste material) based on differences in surface properties. Here’s a detailed overview:
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1. Principle of Flotation
– Froth flotation relies on the hydrophobicity (water-repellent nature) of target minerals.
– Chemicals called collectors selectively bind to desired minerals, making them hydrophobic.
– Air bubbles are introduced into the slurry; hydrophobic particles attach to the bubbles and rise to form a froth layer, which is skimmed off.
– Hydrophilic (water-attracting) gangue particles remain in the slurry and are discarded as tailings.
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2. Types of Flotation Cells
# (a) Mechanical Flotation Cells
– Use an impeller to agitate the slurry and disperse air.
– Common designs:
– Denver cells (classic design with rotor-stator mechanism).
– Wemco cells (self-aerating, no external blower).
– Outokumpu cells (tank-type with efficient mixing).
# (b) Pneumatic Flotation Cells
– Air is injected without mechanical agitation (e.g., Jameson Cell, Column Flotation).
– Ideal for fine particles and high-throughput applications.
# (c) Hybrid Cells
– Combine mechanical and pneumatic features for improved efficiency.
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3. Key Components
– Rotor/Impeller: Agitates slurry and disperses air.
– Stator: Stabilizes turbulence.
– Froth Launder: Collects froth for further processing.
– Air Supply System: Provides controlled airflow (blowers or compressors).
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4. Applications in Ore Beneficiation
– Sulfide Ores: Copper, lead, zinc, nickel (e.g., chalcopyrite, galena).
– Oxide Ores: Hematite, cassiterite (with appropriate reagents).
– Non-metallic Minerals: Phosphate, potash, graphite.
– Coal Cleaning: Removing ash-forming impurities.
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5. Factors Affecting Performance
| Parameter | Impact |
|———–|——–|
| Particle Size | Optimal range: 10–150 µm; fines may require special reagents. |
| pH & Reagents | Collectors, frothers, depressants modify surface
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