To recover titanium from tionite, a new process consisting of NaOH hydrothermal conversion, water washing, and H_2SO_4 leaching for TiO_2 preparation was developed. The experimental results show that under the optimum hydrothermal conversion conditions, i.e., 50% NaOH (mass fraction) solution, NaOH/tionite mass ratio of 4:1, reaction temperature of 240 °C, reaction time of 1 h and oxygen partial pressure of 0.25 MPa, the titanium was mainly converted into Na_2TiO_3, and the conversion was 97.2%. The unwanted product Na_2TiSiO_5 remained stable in water washing, and its formation was prevented by improving NaOH concentration. In water washing process, about 97.6% of Na~+ could be recycled by washing the hydrothermal product. The NaOH solutions could be reused after concentration. 96.7% of titanium in the washed product was easily leached in H_2SO_4 solution at low temperatures, forming titanyl sulfate solution to further prepare TiO_2
