Utilisation of Coal Combustion Product (CCP) from coal-fired power stations is of great interest in Australia. According to ADAA (Ash Development Association of Australia), in 2012, 12.8 Mt (million tonnes) of coal ash was produced from coal fired utilities in Australia . Due to the increase in energy demands, the amount of coal ash continues to increase each year. This increases the pressure on coal and utility industries and associated waste management, to find solutions to the environmental problems that are associated with coal ash production.
One of the good approaches to utilise CCP is to convert fly ash into aggregates as a natural aggregate replacement. The main reasons to consider this approach are: (1) the continuous increasing demands for aggregates and (2) the depletion of the natural aggregate resource. Manufacturing of economical and good quality synthetic fly ash aggregate will reduce the impact of fly ash on the environment and provide a great benefit to economy.
Most fly ashes are physically and chemically suited for production of synthetic aggregates. By using different processing methods, it is possible to produce different qualities of synthetic aggregate in terms of strength, particle shape and density. Therefore, the synthetic aggregate can be more flexible than the natural aggregate as they can be used indifferent applications.
rp1020 synthetic aggregate report (2932627 PDF)