Patent ID: 11898112
Assignee: ASH-TEK, LLC
Field: Environmental technology (Chemistry)
Classification: CPC B  C  F | IPC C

Claim 8:
9. A process for beneficiating landfilled or ponded waste coal fly ash the process comprising:
forming a waste coal fly ash stream having greater than 2% LOI of carbon from waste coal fly ash collected at ambient temperature from a pond or landfill;
subjecting the waste coal fly ash stream to elevated temperatures sufficiently above the ambient temperature to remove at least 75% of the carbon from the waste coal fly ash, the elevated temperature predetermined as a function of at least one of the following characteristics of the collected waste coal fly ash: moisture, LOI, and particle size;
exposing the waste coal fly ash stream to an oxygen-rich atmosphere by introduction of additional air, while subjecting the waste coal fly ash stream to the elevated temperature, the oxygen-rich atmosphere predetermined as a function of at least one of the following characteristics of the collected waste coal fly ash: LOI, hydrolysis, and available carbonates; and
performing the steps of subjecting the waste coal fly ash stream to the predetermined elevated temperature and to the predetermined oxygen-rich atmosphere for a processing time predetermined to reduce the LOI of the waste coal fly ash to 2% or less, thereby forming a beneficiated coal fly ash,
wherein the waste coal fly ash comprises oxidized ash characterized by having coarse waste coal fly ash particles having sizes ranging from 50-635 microns, and wherein the process comprises reducing the coarse waste coal fly ash particle size by 95% during the exposing of the waste coal fly ash stream to heat, and subsequently separating and continually recirculating the coarse waste coal ash particles after the exposure to the heat to form a beneficiated coal fly ash characterized by a minimum of 66% of the beneficiated coal fly ash particles passing through a 44 micron screen,
wherein the elevated temperature is between 900° F. and 1150° F.