Fly Ash is a ultra fine powdery residue (smoke) obtained from any carbon burning process. This fine powder is normally dumped. By identifying the correct source (for example from certain coal fired power stations), the fly ash can be used as a partial cement replacement when making concrete or cementitious products.
Fly ash is used for economical and technical reasons. It is important to select the correct source of fly ash when using the fly ash in order to obtain the maximum technical and economical advantage.
Unclassified Fly Ash (UCFA)
The fly ash that emanates from the power station is analyzed and only diverted to the ULULA ASH plant if it complies with certain technical criteria. This selected but unclassified fly ash is stored and dispatched from the weighbridge into bulk tankers.
Classified Fly Ash(CFA)
Similarly, the fly ash that emanates from the power station is analyzed and only diverted to the ULULA ASH plant if it complies with certain technical criteria. The fly ash is then fed into a classifier which further selects/splits the fine fraction of the diverted fly ash from the coarse fraction. The fine fly ash is then stored and dispatched from the weighbridge into bulk tankers. The remaining coarse fraction is returned to the power station for disposal.
(Ideal particle size and shape after classification)
The fly ash from Kriel Power Station has been comprehensively tested for it’s suitability as a cement extender. This fly ash conforms to the commonly known technical specification such as SANS 1491-2:2005 and EN 450 Type N and S. Kriel Power Station receives all its burning coal from one dedicated source (Kriel Colliery) ensuring a high degree of consistency.