Production of synthetic diopsite for ceramic bodies by using sedimentary sepiolite

Diopsite is important for such characteristics as contributing to the development of mechanical characteristics of ceramic materials, increasing wearing resistance, and increasing whiteness thanks to its high diffraction index.In this study, diopsite phase was produced for ceramic bodies by using -1mm undersize waste Sivrihisar sepiolite, which includes dolomite, and development of the outcome- diopsite phase- was analysed. In order to be used in experimental studies, quartz, as a source of SiO2, and calsit, as a source of CaO, were obtained from Kütahya Porselen A.Ş while sepiolite was obtained from Sivrihisar area.Eight compositions were prepared according to different CaO/MgO and CaO+MgO/SiO2 rates. These compositions were first fired at 1200 ºC and then the resulting phases were analysed. It was seen that in compositions prepared at 1200OC according to CaO/ MgO rates, as well as diopsite phase, phases with high CaO rate (e.g. mervinite, montisellite, akermanite) also developed. Because pure diopsite crystals couldn?t be obtained at 1200ºC, depending on DTA analysis to see the crystallisation heat, the sintering heat of the composition was arisen to 1350ºC., Three different compositions were chosen to be fired at this temperature and their mineralogical analysis were carried out after firing. As a result, development of pure diopsite phase was observed at 1350 ºC.After firing the two compositions at different temperatures; that is, one giving akermanite at 1200ºC as main phase and the other giving diopsite at 1350 ºC, the development of akermanite and diopsite phases were analysed as well as their physical properties.Analysing the physical and mineralogical developments of the composition, in which akermanite phase was high at 1200ºC, at different temperatures, it was determined that as the temperature increased, so did the akermanite phase, and depending on this increase, the physical properties of the composition also rose as well ass its whiteness. Analysing the physical and mineralogical developments of the composition, in which diopsite phase was high at 1350ºC, at different temperatures, it was determined that as the temperature increased, so did the diopsite phase, and depending on this increase, the physical properties of the composition also rose as well. It was also determined that in samples in which akermanite and diopsite developed together as colour development whiteness increased, whereas in samples in which pure diopsite crystals developed, the colour shifted to the green shades which is the natural colour of diopsite crystal.It was determined that in samples prepared by using -1mm undersize Sivrihisar sepiolite, which were stocked as waste and not used, and fired at 1200ºC, as CaO/MgO rate decreased the diopsite phase increased, but pure diopsite phase couldn?t be obtained. In samples fired at 1350ºC, on the other hand, it was determined that as CaO/MgO rate increased vitreous phase rate decreased. In the composition whose CaO/MgO rate was 1.89 and CaO+MgO/SiO2 rate was 0.94, pure diopsite phase was obtained by using sepiolite at 1350OC.