Treatment of fly ash from coal combustion to improve its marketability

Abstract

A system and method for treating unmarketable fly ash and improve its properties as an additive for concrete is disclosed. The method includes the steps of providing a gas stream containing ionized air, and an amount of fly ash containing carbon having all adsorption capacity. The fly ash is then exposed to the gas stream to expose the carbon to the ionized air to promote the attachment of the ions to the carbon to reduce the adsorption capacity of the carbon.

Description

REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of my provisional application having Ser. No. 60 / 852,318, filed Oct. 17, 2006, now abandoned, and includes much of the same material disclosed in my co-pending application filed on even date herewith, titled “Plasma Treatment of Fly Ash From Coal Combustion to Improve Its Marketability.”BACKGROUND OF THE INVENTION[0002]1. Field of Application[0003]Coal combustion fly ash has been marketed for a variety of applications. The addition of fly ash to cement is an expanding industry and accounts for a huge opportunity for the coal burning power plants to defray operating costs for disposal. However if the ash does not meet certain guidelines in terms of residual carbon; or has surfactant adsorption problems-measured in terms of a foam index; or contains ammonia, the fly ash is not only unusable but becomes a disposal problem. This application is concerned with ways and means to treat unmarketable fly ash and improv...

AI Technical Summary

Benefits of technology

[0024]The present application seeks to beneficiate a variety of different coal burning power plant fly ash materials that either have a high foam index problem or are contaminated with ammonia or a combination of these issues and are not marketable into the cement / concrete industry. It also seeks to overcome the shortcomings of the aforementioned methods and provide a safe, economical method of treatment of ash.

[0025]In the methodology of the present application, a surface blocking mechanism is employed that minimizes the energy requirements for processing the ash. It does not require heating. The treatment only modifies superficial layers of the fly ash while the gaseous agent itself has a half-life that is measured in seconds or at most minutes. Fly ash is a commodity and cannot stand high costs in processing to bring it into a marketable state. Accordingly, what is proposed in this application is specifically a low cost method of upgrading the ash merely by localized surface treatment of the offending carbon. The unique aspect of the application is the careful administration of ionized air generated from ambient humid air for ionic treatment of the surface of the carbon utilizing a contacting method and environment operating at, or close to, ambient temperature. (Air is specifically mentioned due to its low cost, although oxygen or oxygen-enriched air may be used, provided there is sufficient humidity in it). Thus, the operational cost of heating material and the associated capital cost of thermal equipment is avoided.MethodDosage g / kg of fly ashIonized0.0040.390.771.55AirInputOutputInputOutputInputOutputInputOutputFoam95709530100259515IndexReduction26.3%68.4%75.0%84.2%MethodDosage g / kg of fly ashOzone0.310.611.223.06InputOutputInputOutputInputOutputFoam958510580105909580IndexReduction10.5%23.8%14.3%15.7%

Problems solved by technology

Fly ash is a commodity and cannot stand high costs in processing to bring it into a marketable state.

Images