The Evolution of Pneumatic Flotation

There is little difference in age between the two major flotation techniques, namely mechanical and pneumatic flotation. But during the last century, from the onset of industrialized mining, mechanical flotation was the predominant technique. Most likely this was due to the greater reliability of mechanical devices, such as rotors and stator assemblies, compared with devices for producing fine air bubbles, such as porous media. In the 1960s the principles of column flotation were adopted, but as computer and PLC control technology was still in developmental stages, the column technique was not overly successful. In the 1970s the trend for larger capacity process flow streams intensified. Large flotation tanks of up to 36 m3 and more became widespread and in the 1980s it was also quite usual to replace cleaner banks with columns to improve concentrate qualities.