Recovery and utilization of fly ash carbons for the development of high-value products

The implementation of increasingly stringent Clean Air Act Regulations by the coal utility industry has generally resulted in an increase in the concentration of unburned carbon in coal fly ash due to the installation of low-NOx burners. Although nowadays the fate of the unburned carbon is mainly disposal, this carbonaceous material is a very attractive precursor for the production of premium carbon products, since it contains >99% carbon and it has gone through a devolatilization process while in the combustor at temperatures well above 1300°C. Accordingly, this work has investigated two potential routes for the generation of premium carbon products from the unburned carbon present in fly ash. The first route focuses on the use of fly ash carbons as precursors for activated carbons by steam activation at 850°C, while the second route concentrates on the utilization of fly ash carbons as a replacement for calcined petroleum coke in the production of carbon artifacts.