The Processing of Fly Ash

Various approaches have been taken to improve/convert the quality of fly ash (PFA) in an attempt to make it more suitable for industrial applications.

The most simple and commonly applied process is to grade by particle size which is then used in various applications by the construction industry. This is referred to as Classified Ash.

Additional improvements have been made by the removal of some carbon in an effort to bring the overall LOI content below the 5% and 7% demanded by BS EN450 :2005 Category A & B for use as an OPC replacement in ready-mix concrete.

Full beneficiation of the fly ash to BS EN450 -2005 Category A is achieved by RockTron using the well established base metal mining technique of froth flotation. Using patented float cells specially designed to handle very fine powders, the carbon content (LOI) is largely separated from the residue of alumino-silicates and magnetite. The latter is then removed using high powered magnetic separators and the alumino-silicates are polished and graded by size.

To view a comparison of the performance efficiency and product qualities with those of another technique, please click here.