Effective Utilization Of Coal Fly Ash Containing Unburned Carbon
Free (open access)
203 - 212
M. Miyake, V. Kumar Jha, Y. Kimura & M. Matsuda
We investigated the conversion process of coal fly ash with unburned carbon at greater than ca. 6 mass%, which has fallen behind in terms of resource recovery. As a result, composite materials consisting of zeolite A and/or zeolite X with good crystallinity and activated carbon were successfully prepared by NaOH fusion treatment at 750°C in N2 flow followed by hydrothermal treatment. The type of zeolite phase formed was dependent on the hydrothermal treatment conditions including NaOH concentration. The resulting composite materials exhibited removal characteristics for heavy metal ions such as Ni2+, Cd2+ and Pb2+. In this paper, we describe the conversion of the main SiO2-Al2O3 components and unburned carbon in coal fly ash into zeolite-activated carbon composite materials by a chemical process and the removal characteristics of the resulting materials. Keywords: coal fly ash, zeolite, fusion treatment, hydrothermal treatment, removal characteristics. 1 Introduction Fossil fuels are of great importance because they can be burned, producing significant amounts of energy. The burning of fossil fuels produces several billion tones of carbon dioxide per year globally. Therefore, in order to reduce the air pollution, several countries have put forward their environmental regulations. Under the regulations, coal-fired power plants will need to reduce their emissions by more than 50% within the next decade. Due to the strict regulations on the burning of coal, coal fly ash (CFA) contains variable amounts
coal fly ash, zeolite, fusion treatment, hydrothermal treatment, removal characteristics.