Patent ID: 6048505
Filing Date: 2000-04-11
Classification: B01J,C01G,C22B

Abstract:
A non-polluting liquid-phase process for producing titanium dioxide pigment from titanium ore or slag which comprises the following steps:a) reacting the ore or slag with sufficient sulfuric acid to obtain a liquid slurry reaction product,b) filtering the reaction product to obtain a filter cake,c) wash-filtering the filter cake with wash water to obtain a further filter cake and filtrate comprising used wash water,d) recycling the filtrate to step (a),e) separating out and recovering, in aqueous solution, water-soluble components of the further filter cake,f) subjecting the water-soluble components, in solution, to hydrolysis to convert titanium values therein to titanium dioxide hydrate,g) calcining the titanium dioxide hydrate to obtain titanium dioxide pigment, and, optionally recycling concentrated sulfuric acid emanating from step (g) to step (a).