Gravity separation

Gravity separation is a method of separating materials by exploiting differences in their density, size, or shape that cause them to settle or move differently under gravity.

Settling: The downward movement of suspended particles or droplets through a fluid under gravity. Gravity separation often depends on particles settling at different rates.
Mineral processing: The treatment of mined material to concentrate valuable minerals and remove waste rock. Gravity separation is one route for upgrading mined ores without chemical extraction.
Density: Mass per unit volume of a substance. Density contrast is the main basis for many gravity-separation processes.
Magnetic separation: A method that separates materials according to their response to a magnetic field. It targets magnetic properties rather than differences in gravitational settling.
Stokes' law: A relation describing the drag force on a small sphere moving slowly through a viscous fluid. It predicts how particle size and density affect settling speed in dilute suspensions.
Coal preparation: The processing of mined coal to remove mineral matter and prepare it for use. Density differences help separate coal from denser rock and mineral impurities.
Particle size: A measure of the dimensions of individual particles in a material. Size affects settling speed and can alter or overwhelm density-based sorting.
Froth flotation: A process that separates particles by selectively attaching them to gas bubbles in a liquid. Surface chemistry, not settling behavior, determines which particles report to the froth.
Hindered settling: The reduced settling speed of particles in a concentrated suspension because neighboring particles impede their motion. Dense particle beds settle collectively rather than behaving like isolated grains.
Placer mining: The extraction of valuable minerals concentrated in sediments by flowing water or other natural processes. Gravity separation explains how dense minerals accumulate in sediment deposits.

Linked from 12 pages