flotação

Flotação, also known as flotation or froth flotation, is a physico-chemical separation process widely used in the mining industry to selectively separate hydrophobic materials from hydrophilic ones. The fundamental principle relies on altering the surface properties of minerals, making some particles attach to air bubbles and float to the surface, while others remain in the water and sink. This is achieved by adding a combination of reagents to a slurry of finely ground ore and water.

A collector is a chemical that selectively adsorbs onto the surface of the desired mineral, rendering it hydrophobic. A frother is then added to stabilize the air bubbles, preventing them from coalescing and ensuring the formation of a stable froth layer. Other reagents, such as depressants and activators, can be employed to further enhance selectivity by either preventing certain minerals from becoming hydrophobic or by making them more amenable to flotation, respectively.

Air is introduced into the conditioning tank or flotation cell, typically through mechanical agitation or sparging. The hydrophobic mineral particles attach to the air bubbles and rise to the surface, forming a mineral-rich froth. This froth is then skimmed off, yielding a concentrate of the desired mineral. The hydrophilic minerals, which have not attached to the bubbles, remain in the pulp and are discharged as tailings. Flotation is a crucial step in the processing of many valuable minerals, including copper, lead, zinc, gold, and coal.