Evaluation of the structure and valence state of titanium oxide in titania slag under microwave heating

The titania slag was utilized to prepare synthetic rutile using microwave roasting at a temperature of 1100 °C for 2 h. The compositions of the titania slag and the changes in the chemical states of the sample resulting from microwave roasting were studied by XRD, SEM, Raman, and XPS, respectively. The XRD results indicate that the product's prominent peaks correspond to the standard card of rutile TiO2 have significantly increased after microwave heating. The Raman vibration peaks at 164.2 cm−1, 203.9 cm−1, and 636.2 cm−1 of the raw materials were caused by Ti3O5, Ti2O3, and anatase TiO2, respectively. After microwave roasting, all the Raman vibration peaks were related to the rutile TiO2 phase. The XPS analysis showed that the surface of the sample mainly contained Ti, C, and O elements, and after microwave roasting, the content of Ti4+ increased significantly. The results indicated that microwave roasting is an effective method to produce rutile TiO2. The roasted product meets the requirements of high-grade synthetic rutile.