Mining - Ore Flotation

Process

Hoffman and Lamson multistage centrifugal blowers are used to supply forced air creating small air bubbles which attach to the conditioned ore particles. The bubbles float to the surface and form a valuable froth layer.

Description

Valuable minerals in ore can be separated from each other and from worthless components by the froth flotation process. Flotation is a key process in the recovery of most of the world’s copper, lead, molybdenum, nickel, platinum group elements, silver and zinc, and in the treatment of certain gold and tin ores. The first step in the flotation process involves crushing the ore. The powder is then mixed with water and chemicals and the resulting pulp or slurry is fed to a series of flotation cells. Most flotation is carried out in large tanks ranging in volume up to 9,000 ft3 (250 m³). The mineral surfaces are made hydrophobic (water repellent) by conditioning with selective chemical reagents. Hoffman and Lamson centrifugal blowers provide air to the cells and the cell contents are mechanically mixed with an agitator to shear the air into bubbles. The bubbles attach to the hydrophobic particles and naturally move upward where they collect in a froth layer at the top of the cell.

Not only does the flotation process enable valuable sulfide minerals to be concentrated from worthless material that make up the ore matrix, but it also allows different sulfide minerals to be separated from each other. Different types of chemical reagents are used to either make mineral particles hydrophobic and rise with the air bubbles or to impede the flotation of minerals by depositing a wetting layer on their surfaces. 

Hoffman™ and Lamson™ Products

Hoffman and Lamson multistage centrifugal blowers are the most well known brand names in the flotation cell industry and have the best reputation for longevity and service. Multistage centrifugal blowers typically operate at higher elevations and range from 3,000 to 20,000 cfm and generally in the 4-7 psi range.