Patent ID: 6375923
Filing Date: 2002-04-23
Classification: B82Y,C01G,C01P,C09C

Abstract:
A hydrometallurgical process for producing pigment-grade titanium dioxide from a titaniferous ore comprising:a. leaching the ore with a solution of hydrochloric acid at a temperature of at least 50Â° C. to provide a leachate containing titanium chloride, ferrous chloride, ferric chloride, and other impurity chlorides, a residue comprising undissolved solids, and an amount of hydrochloric acid to prevent precipitation of titanium dioxide; b. separating the leachate from the undissolved solids; c. reducing ferric ions present in the leachate to the ferrous state; d. cooling the leachate to a temperature sufficient to form crystals of ferrous chloride; e. separating the crystals of ferrous chloride from the leachate to provide a solution containing titanium ions, ferric ions, and ferrous ions; f. contacting the solution with a water-immiscible organic phase containing an organophosphorus extractant to form a first raffinate containing ferrous ions and other impurities and to form a first pregnant strip solution containing titanium and ferric ions and a minor amount of ferrous ions; g. contacting the first pregnant strip solution with a water-immiscible organic phase containing an amine extractant to form a second pregnant strip solution containing ferric ions and to form a second raffinate containing titanium ions; and h. hydrolyzing the second raffinate.