Engulfed nano/micro bubbles for improved recovery of large particles in a flotation cell

A froth flotation apparatus for recovery of selected particles from a mixture of particles, the froth flotation apparatus comprising:

• a first region for receiving the mixture of particles;
• a smaller bubble generator for supplying to the first region first-size bubbles having a first predetermined size to expose the mixture of particles therein to the first-size bubbles, wherein some of the first-size bubbles adhere to surfaces of a selected group of particles of the mixture of particles;
• a second region in communication with the first region for receiving from the first region the mixture of particles including the selected group of particles with some of the first-size bubbles adhered thereto;
• and
• a larger bubble generator for supplying second-size bubbles to the second region to expose the selected group of particles, with the some of the first-size bubbles adhered thereto, to the second-size bubbles, wherein said second predetermined size is at least approximately ten times larger than the first predetermined size, and the second-size bubbles adhere to the surfaces of the selected group of particles and engulf some of the first-size bubbles on the surfaces of the selected group of particles, and the selected group of particles rise to an outlet of the froth flotation apparatus and separate from other particles in the mixture of particles.