In BUBBLE SEPARATOR, bubbles are introduced into a pulp and the bubbles rise through the pulp. In the process, hydrophobic particles become bound to the surface of the bubbles. The driving force for this attachment is the change in the surface free energy when the attachment occurs. These bubbles rise through the slurry and are collected from the surface. To enable these particles to attach, careful consideration of the chemistry of the pulp needs to be made. These considerations include the pH, Eh and the presence of flotation reagents. The pH is important as it changes the charge of the particles surface and the Eh affects the chemisorptions of collectors on the surface of the particles.
The addition of flotation reagents also affects the operation of these processes. The most important chemical that is added is the collector; This chemical binds to the surface of the particles as it is a surfactant. The main considerations in this chemical are the nature of the head group and the size of the hydrocarbon chain. The hydrocarbon tail needs to be short to maximize the selectivity of the desired mineral and the head group dictates which minerals it attaches to.