Figure 1. Simplified process diagram showing key steps in the sulfate process for production of refined TiO2

The older sulfate process, illustrated in Figure 1, is a batch process that entails the digestion of crude TiO2 or FeTiO3 ores with sulfuric acid to form titanyl sulfate (TiOSO4), and the separation of the metal impurities as sulfate salts, e.g. iron(II) sulfate.