A novel preparation of titanium dioxide from titanium slag

A novel method of caustic hydrothermal decomposition of titanium slag followed by acidification of the sodium titanate product was adopted to prepare titanium dioxide. The effects of temperature, sodium hydroxide concentration, alkali-to-titanium slag mass ratio and reaction time on the titanium extraction were studied. Almost complete extraction of titanium was achieved when finely ground titanium slag (− 61/+51 μm) was reacted with a NaOH solution with a concentration of 10 mol kg− 1 H2O and the alkali-to-titanium slag (based on TiO2) mass ratio of 4:1 at 220 °C for about 4 h. The XRD pattern shows that the hydrothermal product obtained under optimal conditions was Na4Ti3O8. Titanium dioxide with a rutile structure was obtained by acidification and cation exchange of Na4Ti3O8. The effects of pH value, temperature, mass ratio of liquid-to-solid, and different acid medium on the product of cation exchange were studied together with the variation of titanium and iron concentration in solution. Under optimal conditions, the purity of titanium dioxide was > 99.0%.