Coal-fired power plants in the United States generate about 75 million tons of coal ash annually. Compared with the 267 million tons of trash that Americans generate per year, it makes sense to find alternative uses for coal fly ash to keep landfills from being overwhelmed with this residual matter.
On the plus side, approximately fifty-eight percent of the coal ash generated in 2018 was recycled. One way to do that is to use it in the production of concrete. The Romans used a mixture of volcanic ash mixed with lime to create a very effective kind of concrete. It was invented Long before portland cement.
Using fly ash from coal-fired power plants creates a similar chemical reaction when used in the production of concrete, which makes it a suitable substitute for cement substitution. The significance of keeping fly ash out of landfills is huge, but there’s more to the environmental equation.
When portland cement cures, it leaves behind some of the hydrated lime. That is added with water to create a binding agent. When fly ash is used in place of cement, it allows the lime to cure as well. Contributing to added strength and durability of hardened concrete in comparison to cement alone.
More importantly, it significantly reduces the amount of energy needed to produce portland cement. Nearly a ton of carbon dioxide is emitted in the production of a ton of portland cement. While it is already combusted and therefore does not release additional CO2 upon being used in concrete. For each ton of cement replaced by fly ash in a concrete mixture, it can avoid a ton of carbon dioxide emissions.
Recycling fly ash does help to keep landfills from being overburdened. Further, it also reduces the amount of energy needed to produce concrete as well as the amount of carbon dioxide released into the atmosphere during the concrete production process.
The key to the strength and durability of building products made with fly ash is to reduce its carbon content and control its quality. The ST Equipment & Technology’s triboelectrostatic belt separator can remove residual carbon coal char and generate a high quality consistent processed product, ProAsh®, a valuable material for concrete producers. We are dedicated to helping our customers and the world we live in. Contact us today for more information.