MineralProcessing Flashcards
HOW CAN ORE MINERALS BE BROKEN DOWN
HEAT - PYROMETALLURGY
Solvents - Hydrometallurgy
Electricity - Electrometallurgy
Can be a combination of these
What are the two fundamental operations in mineral processing?
- Liberation - The release of valuable minerals from gangue
- Concentration - the separation of the valuable minerals from gangue
How is liberation achieved?
Through communition - Crushing and grinding. Grinding is often the most energy intensive part of the concentrators energy requirements often accounting for up to 50% of the energy requirements.
In order to produce clean concentrates with little contamination with gangue minerals, it is necessary to grind the ore finely enough to liberate the associated meta
What are the problems with fine grinding?
Fine grinding, however, increases energy costs, and can lead to the production of very fine untreatable “ slime” particles which may be lost into the tailings. Grinding therefore becomes a compromise between clean (high-grade) concentrates, operating costs and losses of fine minerals. I
What are the most common methods for concentrating ores?
Sorting/Screening - Based on optical / size properties
Gravity Concentration - based on the differential movement of mineral particles in water due to their different hydraulic properties.
Froth Flotation - Separation utilising the different surface properties of the minerals. Froth flotation is effected by the attachment of the mineral particles to air bubbles within the agitated pulp. By adjusting the “ climate” of the pulp by various reagents, it is possible to make the valuable minerals air-avid (aerophilic) and the gangue minerals water-avid (aerophobic). This results in separation by transfer of the valuable minerals to the air bubbles which form the froth floating on the surface of the pulp.
Magnetic Separation - Seperation dependant on magnetic properties (useful for magnetite, tin and even mineral sands)
