What is in bottom ash?
Bottom ash and boiler slag are composed principally of silica, alumina, and iron, with smaller percentages of calcium, magnesium, sulfates, and other compounds. The composition of the bottom ash or boiler slag particles is controlled primarily by the source of the coal and not by the type of furnace.
What is the difference between fly ash and bottom ash?
During coal combustion, large amounts of ash are created along with carbon dioxide and other gases. The fine particle ash that rises up with the flue gases is known as fly or flue ash while the heavier ash that does not rise is called bottom ash; collectively these are known as coal ash.
What does bottom ash look like?
These particles are formed at the bottom of the furnace. Bottom ash consists of coarser and heavier particles than fly ash (Torrey, 1978). The color of bottom ash ranges from gray to black. Bottom ash has an angular texture, and it is a relatively well-graded, sand-sized material (Huang and Lovell, 1990).
How is bottom ash produced?
Bottom ash is the coarse, granular, incombustible by-product of coal combustion that is collected from the bottom of furnaces. Most bottom ash is produced at coal-fired power plants.
Why is it called fly ash?
Corrosionpedia Explains Fly Ash Fly ash is a residue generated in combustion and comprises the fine particles that rise with the flue gases. Ash that does not rise is called bottom ash. In an industrial context, fly ash usually refers to ash produced during combustion of coal. Fly ash is a heterogeneous material.
What is used to remove bottom ash from emissions?
Prior to exhausting the flue gas, fly ash is removed by particulate emission control devices, such as electrostatic precipitators or filter fabric baghouses (see Figure 1-1).
What is washed bottom ash?
The WBA is a waste material that is taken from electric power plant and the source material is called as bottom ash. To substitute the amount of carbon usage in concrete the bottom ash was utilized and fully submerged in water for 3 days to produce as WBA with low carbon composition.
What is LOI in fly ash?
LOI is a measurement of unburned carbon (coal) remaining in the ash and is a critical characteristic of fly ash, especially for concrete applications.
Why do you use fly ash in concrete?
Introduction. The use of fly ash in portland cement concrete (PCC) has many benefits and improves concrete performance in both the fresh and hardened state. Fly ash use in concrete improves the workability of plastic concrete, and the strength and durability of hardened concrete. Fly ash use is also cost effective.
Why is fly ash used in concrete?
What is the specific gravity of fly ash?
The specific gravity of fly ash usually ranges from 2.1 to 3.0, while its specific surface area (measured by the Blaine air permeability method)(6) may range from 170 to 1000 m2/kg. The color of fly ash can vary from tan to gray to black, depending on the amount of unburned carbon in the ash.
What is fly ash How is it harmful?
Fly ash particles (a major component of coal ash) can become lodged in the deepest part of your lungs, where they trigger asthma, inflammation and immunological reactions. Studies link these particulates to the four leading causes of death in the U.S.: heart disease, cancer, respiratory diseases and stroke.