Production and Characterization of Porous Ceramics From Coal Fly Ash and Clay

Abstract

The disposal of coal fly ash obtained in thermal power plants presents the general problem all over the world. Significant research on the utilization of fly ash has been carried out in the area of construction materials. The aim of this study was to develop porous ceramics based on coal fly ash and clay (60wt.%clay and 40wt.% fly ash). Three types of pore creators: two types of wood cutting (Quercus and Facus sylvatica) and C-powder were used for creating of the porous ceramics. The mixtures based on fly ash and clay and different content of pore creators (2, 5, 10 and 20wt.%) were consolidated (P=45 MPa, T = 900, 1000, 1050 and 1100oC/1h) to obtain porous ceramic (PC). The results indicate that the properties of the porous ceramics depend on the type and content of the pore creators. Furthermore, the sintering temperature was found to be main factor affecting the properties of the sintered products. The maximal bending strength (26 MPa) was achieved by using 2wt% P3 (C-powder) and the porous ceramics has the density and porosity of 1.90g/cm3 and 22%, respectively. By using the highest content (20wt.% ) of each pore creator (P1, P2 and P3) the lowest bending strength cca 5 MPa was achieved and the variation of the density and porosity was in the range from 1.22 to 1.32 g/cm3 and 44 to 48%, respectively. Water absorption, durability and the microstructure of the obtained porous ceramics are also reported in this paper.