kelluttaminen

Kelluttaminen is a mineral processing method used to separate valuable minerals from gangue by making the target minerals hydrophobic so that they attach to air bubbles in a water-based pulp and rise to the surface as a froth. The term is widely used in Finnish-language mining literature, and the corresponding English term is flotation.

The process typically starts with ore that has been ground to a fine particle size and mixed with water to form a slurry. Reagents are added to modify surface properties and separation behavior: kelluttimet (collectors) render the desired minerals hydrophobic, vaahduttimet (frothers) help stabilize the bubble froth, and pH modifiers or promoters tailor the system for selectivity. Air is introduced to generate bubbles, to which the hydrophobic mineral grains attach and migrate upward. The froth that forms at the surface is skimmed off as the concentrate, while the remaining slurry, called the tailings, remains in the pulp.

Equipment and variations include mechanical flotation cells, column flotation, and specialized designs such as Jameson cells. Column flotation can provide higher grade concentrates with different mineral systems, while mechanical cells are common in many milling circuits. Flotation is used for a wide range of minerals, especially sulfide ores (such as copper, zinc, and lead) and various non-sulfide minerals, as well as in coal beneficiation and certain industrial minerals.

Environmental and economic considerations include reagent consumption, tailings management, water reuse, and energy use. Flotation remains a central technology in mineral processing due to its versatility, efficiency, and adaptability to different ore types.