Invastigation of grinding fly ash and steel slag usability inglass ceramic

In this thesis study, the effect of grinding processes on sintering behavior of the mixture of fly ash (FA) waste obtained from Çayırhan (Ankara) Thermal Power Plant and basic oxygen furnace (BOF) slag obtained from Erdemir Iron and Steel Factory as auxiliary material in different proportions was investigated in a planetary ball mill for 2, 4, 8, 12 and 16 h. In the first phase of the study, Particle Size Distribution (PSD), X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) analyzes were performed to investigate the mineralogical and microstructural effects of the grinding process on the waste material. It has been revealed from the scanning electron microscope (SEM) images that the particles has started to clump after 8 hours of milling time. It shows that the grinding process plays an important role in the PSD of FA, but this size increases again at the 16 h grinding time. In the second phase of the study, in order to determine the optimum sintering conditions depending on the grinding time and mixing ratios parameters. Firstly, FA and BOF slag used as auxiliary material in different proportions were grinded wet for 2, 4, 8, 12 and 16 h. After grinding, the samples were pressed into cylindrical form without using any additives, binders etc. The samples formed were sintered at four different temperatures: 950°C, 1000°C, 1050°C and 1100°C, their mechanical, mineralogical and microstructural properties have been determined. As a result of the compressive strength tests, it has been concluded that the strength values have varied between 4.56 and 83.95 MPa. The highest strength value was obtained as a result of grinding the mixture of 2/3FA and 1/3BOF slag for 8h and sintering at 1050oC