Methods of treating bi-modal fly ash to remove carbon

摘要

A method of reducing the carbon content of a dry bi-modal fly ash includes subjecting the bi-modal fly ash to dry vibrating screen separation into a carbon rich component and a carbon depleted fly ash component with the carbon depleted fly ash component being created with a carbon content less than about 4 percent by weight and at least 50 weight percent of the fly ash component of the bi-modal fly ash. The dry vibrating screen separation is preferably a single step process with no prior substantial concentration of the carbon component of the bi-modal fly ash. It is preferred to employ bi-modal fly ash produced as a result of combustion of coal. A method of making a concrete mixture employing the carbon depleted component is also provided.