Froth flotation is a separation technique used in mineral and coal processing to separate hydrophobic particles from hydrophilic ones. This separation technique is done in large cells or columns filled with water. Basically, the hydrophobic particles stick to air bubbles, which then float to the top of the water; while the hydrophilic particles sink. As more bubbles collect at the top of the water, they form a "froth" which can then be scraped to concentrate the hydrophobic minerals. In coal preparation, the coal tends to float; likewise, in metal ore processing, metal sulfide minerals tend to float. Chemical treatments can be used to alter the surfaces to make certain minerals even more or less hydrophobic or hydrophilic than they are naturally, and also to aid in froth formation.

Examples of froth flotation for mineral processing:

- separating phosphate from silicates

- separating silicates from iron ores

- separating coal from ash minerals

- separating sylvite from halite

- separating sulfides from silicates