Why are different chemical reagents used in cobalt flotation?

In the context of cobalt processing, different chemical reagents are used during the flotation process to selectively attract cobalt minerals to air bubbles.

This selective attraction is necessary to separate cobalt-rich minerals from other materials, such as copper, within the concentrate. By utilizing specific reagents, processors can ensure that cobalt particles adhere to the bubbles created by pneumatic and mechanical agitation, allowing them to be carried to the surface for collection and further pyrometallurgical or hydrometallurgical treatment.1