Process for beneficiating fly ash, beneficiated fly ash, and cementitious compositions containing beneficiated fly ash

摘要

A non-conforming fly ash is converted into conforming fly ash by: (1) obtaining an initial fly ash with at least one non-conforming characteristic selected from excess carbon or low reactivity index as defined by ASTM C-618 and having a D10, D50 and D90; (2) classifying the initial fly ash using one or more air classifiers to produce at least two separate fly ash streams, including fine fly ash and coarse fly ash; and (3) collecting the fine fly ash and the coarse fly ash, (4) the fine fly ash having a D90 approximately equal to or less than the D50 of the initial fly ash and a conforming carbon content and a conforming reactivity index as defined by ASTM C-618.