Fly ash is a material produced during the combustion of coal or biomass in power plants. It consists of fine particles that are transported out of the combustion chamber via the exhaust gas flow during the combustion process. The dust-like ash is carried along in the flue gases and settles in the filters of the waste gas purification systems.
Fly ash consists mainly of mineral components such as silicon dioxide, aluminum oxide, iron oxide and calcium oxide. Depending on the type of fuel used and the combustion technology, the composition of fly ash may vary.
In the power plant industry, fly ash is often considered a resource that can be reused. It can be used as an aggregate in cement production to improve the strength and durability of cement. Fly ash can also be used in the production of concrete, asphalt and various construction materials to improve their properties.
The use of fly ash in the cement industry is an effective way to conserve resources, reduce CO2 emissions and promote a sustainable circular economy.
Hard coal fly ash, a by-product of burning coal (and biomass if applicable) in power plants, contains a variety of mineral constituents that can impart valuable properties in cement production. Considerable environmental benefits can be achieved by integrating fly ash as an aggregate in cement.
A major advantage of using fly ash is that less cement clinker is needed. Clinker is a main component of cement and is produced by burning limestone, clay and iron oxide at high temperatures. This process is energy intensive and contributes significantly to CO2 emissions. By replacing part of the clinker with fly ash, the cement manufacturing process can be made more resource-efficient and climate-friendly overall.
Fly ash also acts as an activator that improves the strength and durability of the cement. It promotes better particle distribution and the formation of additional calcium silicate hydrates, which are responsible for strength development. Thus, the use of fly ash can optimize the technical properties of the cement and ensure higher quality.
In addition, the use of fly ash in the cement industry plays an important role in promoting a sustainable circular economy. Instead of fly ash being landfilled as waste, it is used as a valuable raw material. This helps conserve natural resources by reducing the need for clinker and other primary materials.
However, the integration of fly ash into the cement manufacturing process requires careful planning and control. The chemical composition of fly ash can vary, depending on the type of fuel used and the combustion process. Therefore, it is important to analyze the quality and properties of the fly ash and carefully dose the quantity to ensure optimum performance of the cement. In addition, appropriate dust control and environmental protection measures should be taken to minimize potential risks associated with the handling and storage of fly ash.