Belit-Calciumsulfoaluminate-Cement from lignite and hard coal fly ash

Project Number 404

The production of cement causes high CO₂ emissions. One way to reduce these emissions is the reduction of CO₂ in the basic materials by use of industrial by-products as secondary raw material for the raw meal or Belit-based cements for example. Belit is one of the clinker phases of cement.

Aim of the project is the production of a Belit-Calciumsulfoaluminate-Cement from fly ash raw meal. Lignite and hard coal fly ash will be used for that, and to improve the hydraulic activity calcium sulfate will be added.

Both fly ash types will be used to investigate the effect of the different composition of the raw meal on the formation of the clinker phases. The advantage of such a system is to get cement with good early strength out of a process with low firing temperatures and low CaO-content. This makes it a good alternative to the well-known clinker and cements from the economic and technical point of view.

Within this project the development of hydration will be measured by means of x-ray analysis and thermal flux calorimetry. In addition to that the strength development of the Belit-Calciumsulfoaluminate-Cements will be tested over a period of 90 days.

In case of successful tests, a new application area for both types of fly ash, lignite and hard coal, will be available. This leads to an enlarged application of fly ash in concrete.

The project is assigned to the VGB focal point research programme "Waste Management of Coal-fired Power Plants and Waste Incineration Plants" (ERKOM) and is supervised by the VGB Technical Group Power Plant By-products.