Separation of Fe3+ during hydrolysis of TiO2+ by addition of EDTA

White pigment (titanium dioxide, TiO2) is used in various fields due to its exceptional stability, and optical and electronic properties. The complete removal of Fe3+ during the manufacturing process of white pigment is essential. This paper introduces a method to prepare high purity TiO2 by addition of EDTA (disodium ethylenediammine tetra-acetate) to chelate Fe3+ and prevent its hydrolysis to form Fe(OH)3. The extent of hydrolysis of the TiO2+ ion rose with increasing solution pH and greater time under the experimental conditions, reaching 94.8% at a solution pH of 1.68 and a hydrolysis time of 150 min. Under the experimental conditions, the hydrolysis of Fe3+ was restrained by EDTA addition into the solution. The TiO2 content of the product rose an increase of the EDTA/Fe3+ molar ratio, yielding a purity of 99.9% TiO2 as the ratio increased to 3. EDTA addition reduced the initiation of TiO2+ hydrolysis and the required amount of deionized washing water because larger meta-titanic acid grains were produced which were easily filtrated and washed.