Natural CaO-TiO2-SiO2 based ceramics

Le nica river deposits consist of a large number of minerals of different grain sizes including sphene. Since it is very difficult to obtain pure monophase titanite by different synthetic routes (sol-gel, coprecipitation, combustion, spray pyrolysis and hydrothermal method), the aim of this work was to study the structure of the sphene from the Le nica river deposits and possibility of using it as a natural precursor for CaO-TiO2-SiO2 based ceramics. The sphene from Le nica was analyzed by different methods: tristimulus colorimetry, infrared spectroscopy, electron microprobe and X-ray single crystal diffraction. It was confirmed that Al, Fe, Mn and P are present in the sphene structure and proposed that corresponding structural formula could be: (Ca2+1.008 Mn2+0.002)1.010(Ti4+0.901 Fe3+0.033 Al3+0.060 P5+0.001)0.995 Si4+1.024 O2-5.