Abstract: A non-polluting liquid-phase process and a supporting system of apparatus for producing titanium dioxide from titanium ore or slag provide a more economical sulfate process for preparing anatase. The ore or slag is reacted with hot sulfuric acid. The reaction product is filtered and washed before being combined with acid water, in which the solids are partially dissolved. The resulting suspension is filtered, and the filtrate hydrolyzed to convert titanium values therein to titanium dioxide hydrate, which is calcined to produce anatase pigment.

Abstract: An economic, non-polluting vapor-phase system of extracting titanium values from titanium ore or slag comprises solubilizing titanium (in ore or slag) with sulfuric acid to form titanyl sulfate, hydrolyzing the titanyl sulfate to form titanium oxide hydrate, converting the latter to pigment, and recycling sulfuric acid for extracting titanium values from further ore or slag. Methodology and equipment are provided.

Abstract: Alkali-metal bisulfate is employed in a non-polluting and economically-feasible system for producing titanium dioxide pigment from titanium mineral or slag with recycling of alkali-metal bisulfate and ammonia.