Patent ID: 8398954
Filing Date: 2013-03-19
Classification: B01J,C01G,C09C

Abstract:
1. A process for the production of a white titanium dioxide pigment, the process comprising the steps of: (a) reacting a titanium ore containing iron with an aqueous NH (b) filtering the aqueous suspension into a sludge fraction and a filtrate fraction, the filtrate fraction comprising ammonium oxofluorotitanate; (c) subjecting the filtrate fraction to a hydrolysis reaction to obtain an aqueous dispersion; (d) filtering the aqueous dispersion prior to a first thermal hydrolysis reaction to obtain a solid component comprising ammonium oxofluorotitanate; (e) subjecting the solid component to the first thermal hydrolysis reaction in a first reactor in the presence of steam to release a first quantity of HF and NH (f) passing the solid component to a second reactor connected in series with the first reactor; (g) subjecting the solid component to a second thermal hydrolysis reaction in a second reactor in the presence of steam to release a second quantity of HF and NH