What role do air bubbles play in nickel ore flotation?

In nickel ore flotation, air bubbles serve as the primary transport mechanism for separating valuable minerals from waste material. During the process, the ore is mixed with specific chemical reagents that coat the surface of the nickel-bearing sulfide particles, making them hydrophobic (water-repellent).12

When air is introduced into the mixture through mechanical or pneumatic agitation, these treated sulfide particles adhere to the surfaces of the rising air bubbles. The bubbles carry the mineral particles to the surface of the mixture, where they collect as a froth or concentrate. This process effectively lifts the desired nickel minerals out of the suspension, while the unwanted waste material, or tailings, remains behind or sinks to the bottom. By concentrating the nickel in this manner, the process allows for the efficient extraction of minerals that would otherwise be lost.1234