Fly ash carbon passivation
A thermal method to passivate the carbon and/or other components in fly ash significantly decreases adsorption. The passivated carbon remains in the fly ash. Heating the fly ash to about 500 and 800 degrees C. under inert gas conditions sharply decreases the amount of surfactant adsorbed by the fly ash recovered after thermal treatment despite the fact that the carbon content remains in the fly ash. Using oxygen and inert gas mixtures, the present invention shows that a thermal treatment to about 500 degrees C. also sharply decreases the surfactant adsorption of the recovered fly ash even though most of the carbon remains intact. Also, thermal treatment to about 800 degrees C. under these same oxidative conditions shows a sharp decrease in surfactant adsorption of the recovered fly ash due to the fact that the carbon has been removed. This experiment simulates the various "carbon burnout" methods and is not a claim in this method. The present invention provides a thermal method of deactivating high carbon fly ash toward adsorption of AEAs while retaining the fly ash carbon. The fly ash can be used, for example, as a partial Portland cement replacement in air-entrained concrete, in conductive and other concretes, and for other applications.
- Research Organization:
- National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV (United States)
- Sponsoring Organization:
- USDOE
- Assignee:
- Waynesburg University (Waynesburg, PA); U.S. Department of Energy (Washington, DC)
- Patent Number(s):
- 8,440,015
- Application Number:
- 12/803,306
- OSTI ID:
- 1128491
- Country of Publication:
- United States
- Language:
- English
Similar Records
An examination of fly ash carbon and its interactions with air entraining agent
The effect of low-NO{sub x} combustion on residual carbon in fly ash and its adsorption capacity for air entrainment admixtures in concrete