How does gravity separation use density differences between minerals?

Gravity separation utilizes the density differences between minerals to concentrate valuable materials from gangue. Because minerals possess varying densities, they respond differently to forces applied within a fluid medium, such as water or a heavy-media suspension.1

Common techniques include:

• Heavy-media separation: Ground ore is placed in a suspension with a density higher than water. Denser, valuable minerals sink, while lighter gangue particles float and are removed.1
• Jigging: A pulsed water stream creates an oscillating motion that stratifies a bed of material into layers based on density, with the heaviest minerals settling at the bottom.1
• Flowing-stream separation: Systems like spirals use centrifugal force to concentrate heavier particles toward the inner side of a channel as pulp flows downward.1
• Shaking tables: These use a combination of flowing water and mechanical vibration to stratify particles on an inclined plane, effectively separating fine-grained ores like tin and tungsten.1

These methods are essential for processing specific ores, though they differ from flotation, which relies on surface chemistry rather than density.12