Bottom ash

Bottom ash is a by-product of coal combustion in power plants. It is the heavier component that falls to the bottom of the furnace during the combustion process, hence the name "bottom ash". This material is different from fly ash, which is the lighter component that rises with flue gases.

Composition

Bottom ash is primarily composed of large, coarse particles of oxide materials. These include silicon dioxide, aluminum oxide, and iron(III) oxide. It also contains trace amounts of other elements, such as calcium, magnesium, and sulfur. The exact composition can vary depending on the type of coal being burned and the specific power plant.

Uses

Despite being a waste product, bottom ash has several practical uses. It can be used in road construction as a sub-base material, in concrete as a replacement for aggregate, and in land reclamation projects. It is also used in the production of cement and bricks.

Environmental Impact

The disposal of bottom ash can have significant environmental impacts. It can contaminate groundwater with heavy metals and other pollutants if not properly managed. However, the reuse of bottom ash in construction and other applications can help to mitigate these impacts.

Regulation

In many countries, the disposal and reuse of bottom ash is regulated by environmental laws. For example, in the United States, the Environmental Protection Agency (EPA) regulates the disposal of bottom ash under the Resource Conservation and Recovery Act (RCRA).

See Also

• Coal combustion products
• Fly ash
• Environmental impact of the coal industry