Fly ash

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fly ash

[′flī ‚ash]
(engineering)
Fine particulate, essentially noncombustible refuse, carried in a gas stream from a furnace.
Coal combustion residue.

Fly ash

A fine glass powder recovered from the gases of burning coal during the production of electricity. It is an ash residue from high-temperature combustion processes. Electric motor plants using western coal produce a nontoxic fly ash that because of its very high calcium content can be a substitute for Portland cement, the common bonding material in concrete, and these micron-sized Earth elements consist primarily of silica, alumina, and iron. When mixed with lime and water, fly ash forms a cementitious compound with properties very similar to that of Portland cement. Because of this similarity, fly ash can be used to replace a portion of cement in the concrete, providing some distinct quality advantages. The concrete is denser, resulting in a tighter, smoother surface with less bleeding. Fly ash concrete offers a distinct architectural benefit with improved textural consistency and sharper detail. Regulations vary from state to state; however, ASTM International suggests that fly ash must not contain more than 6 percent unburned carbon to be used for its cementitious qualities. Substitution of fly ash for Portland cement in concrete is considered a sustainable building strategy, as it reduces the amount of energy-intensive (and CO2-producing) cement in the mix.

fly ash

The finely divided residue resulting from the combustion of ground or powdered coal, transported from the firebox through the boiler by flue gases.

fly ash

as the aggregate.
References in periodicals archive ?
There is an influence of sawdust on the compressive strength of the alkali-activated material based on fly-ash.
ALKALI-ACTIVATED MATERIALS BASED ON FLY-ASH WITH A SAWDUST ADDITION
According to the Slag Cement Association, slag cement can be used as a replacement up to 50 percent in normal concrete applications, with fly-ash as high as 30 percent.
ARTBA has been actively engaged in the regulatory and legislative debate in Washington over fly-ash since 2007 and applauded the decision as a "win-win" for both the taxpayer and the environment.
In addition, the project will: Reduce the amount of waste going to landfill; Save natural resources by recycling fly-ash, oil drilled wastes and metallurgical slag instead of using raw minerals;
Under the leadership of this professional management team, the partnership (Maxam and Xcentia companies) is receiving considerable interest from potential fly-ash and mining commercial customers.
Additional details on the Fly-Ash and the Desalinization initiatives were announced earlier this year and can be found on the Maxam Gold web site.
In recent months Maxam has announced agreements with organizations for the purpose of improving revenues by extracting marketable elements from fly-ash and other CCPs using the Maxam proprietary process, which in turn provides for a cleaner environment.
will install equipment to separate unburned carbon from fly-ash at Carolina Power & Light Company's (CP&L) Roxboro, N.