Vaahdotusmenetelmä

Vaahdotusmenetelmä, or flotation method in English, is a separation process used to selectively separate hydrophobic materials from hydrophilic materials. It is commonly employed in mineral processing to concentrate valuable minerals from ore, but also finds applications in wastewater treatment and recycling.

The core principle of flotation relies on modifying the surface properties of the particles to be separated. This is achieved by adding specific chemicals, known as collectors, which selectively adsorb onto the surface of the desired mineral, making it hydrophobic. A frother is also added, which creates a stable foam when air is bubbled through the mixture.

In a flotation cell, finely ground ore or material is mixed with water and these reagents. Air is then introduced, forming bubbles. The hydrophobic particles, now coated with the collector, attach to the air bubbles and rise to the surface, forming a froth. This froth, containing the concentrated valuable material, is then skimmed off. The hydrophilic particles, which have not been rendered hydrophobic, remain in the water and are discharged as tailings.

The efficiency of the flotation method depends on various factors, including the type and concentration of reagents, particle size, pH of the slurry, and the amount of air introduced. Different types of flotation exist, such as froth flotation, dissolved air flotation, and pneumatic flotation, each with its specific advantages for different applications. It is a widely used and effective technique for mineral beneficiation and other separation tasks.