The process of separating a mineral from its ore depends on the type of mineral and the composition of the ore. Here are the general steps involved in mineral extraction and separation:
1. Crushing and Grinding (Comminution)
– The mined ore is first crushed into smaller pieces using jaw crushers, cone crushers, or impact crushers.
– Further grinding (using ball mills or rod mills) reduces the ore to a fine powder to liberate the mineral particles from the waste rock (gangue).
2. Concentration (Beneficiation)
This step aims to increase the mineral content by removing unwanted material. Common methods include:
# a. Gravity Separation
– Used for heavy minerals like gold, tin, or tungsten.
– Techniques include:
– Jigging – Uses pulsating water to separate denser minerals.
– Spiral Concentrators – Relies on centrifugal force.
– Shaking Tables – Separates particles based on density differences.
# b. Froth Flotation
– Used for sulfide ores (e.g., copper, lead, zinc).
– Chemicals (collectors and frothers) are added to make mineral particles hydrophobic.
– Air bubbles carry the mineral to the surface as froth, while gangue sinks.
# c. Magnetic Separation
– Used for iron ore (magnetite) and other magnetic minerals.
– A magnet separates magnetic minerals from non-magnetic gangue.
# d. Electrostatic Separation
– Used for minerals like rutile or monazite.
– Electric charges separate conductive from non-conductive particles.
# e. Leaching (Chemical Extraction)
– Used for gold, copper, and uranium ores.
– A chemical solution (e.g., cyanide for gold, sulfuric acid for copper) dissolves the metal, which is later recovered through precipitation or electrowinning.
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3. Dewatering (Solid-Liquid Separation)
– After concentration, excess water is removed using:
– Thickeners
– Filter presses
– Centrifuges
4. Smelting & Refining (For Metals)
– If the product is a metal (e.g., copper, iron), further processing may be needed:
– Smelting: High-temperature melting removes impurities (e.g., blast furnace for iron).
– Refining:
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