How are ore minerals separated from gangue after mining?

After mining, ore is typically crushed into fine particles to facilitate the separation of valuable minerals from waste rock, known as gangue. This process, collectively called mineral processing, utilizes several techniques based on the physical and chemical properties of the materials:

• Flotation: Widely used for sulfide ores, this method involves agitating finely ground ore with water and specific chemicals. These chemicals make the desired mineral particles hydrophobic (water-repellent), allowing them to adhere to air bubbles and float to the surface as a froth, while the gangue sinks.12
• Gravity Separation: This relies on density differences. Techniques include heavy-media separation, where gangue floats in a dense suspension; jigging, which uses pulsating water to layer materials by density; and the use of spirals or shaking tables to separate particles in flowing water.3
• Magnetic Separation: This exploits the varying magnetic susceptibility of minerals. Magnetic fields are used to pull magnetic minerals away from non-magnetic gangue.4
• Hydrometallurgy: This involves dissolving the metal from the ore using aqueous solutions, such as dilute sulfuric acid, followed by chemical or electrolytic recovery.56