Production of rutile from ilmenite

Claim 1

The method for the production of titanium dioxide in rutile form from ilmenite which comprises the steps of: a. mixing ilmenite ore with calcium sulfate in a proportion of 1:10 to 10:1; b. heating said mixture with hydrogen at temperatures in the range 1500° to 1800° F for up to 1 hour to reduce the iron in the ilmenite ore to metallic iron and the calcium sulfate to calcium sulfide; c. magnetically separating the reduced mixture to form a magnetic fraction containing the iron and the TiO 2 content of the ores, and a non-magnetic fraction comprising the calcium sulfide and non-TiO 2 gangue, and segregating the non-magnetic fraction; d. leaching said magnetic fraction with a ferric chloride solution thus dissolving said metallic iron and filtering the leached fraction leaving the TiO 2 -components as a residue; e. dissolving the TiO 2 residue in concentrated sulfuric acid to form a titanyl sulfate solution thereof; f. adding at least one mole equivalent of calcium chloride solution to said titanyl sulfate solution to form a solution of titanyl chloride and a precipitate of insoluble calcium sulfate; g. separating said insoluble calcium sulfate precipitate from said titanyl chloride solution; h. hydrolyzing said titanyl chloride solution by the addition of water and heat, thus precipitating titanium oxide hydrate and liberating gaseous hydrochloric acid; i. calcining said titanium oxide hydrate to form TiO 2 in rutile form; j. recycling the liberated hydrochloric acid from (h) to react with the calcium sulfide of the non-magnetic fraction obtained at (c) to form the calcium chloride used in step (f); k. recycling the calcium sulfate precipitate, separated at (h), to mix with fresh ilmenite at (a); l. oxidizing the leached iron-containing solution with an oxygen-containing gas to precipitate iron oxide (Fe 2 O 3 ) from said solution and regenerating ferric chloride solution for use in step (d).

Claim 2

The method for the production of titanium dioxide in rutile form from ilmenite which comprises the steps of: a. mixing ilmenite ore with calcium sulfate in a proportion of 1:10 to 10:1; b. heating said mixture with hydrogen at temperatures in the range 1500° to 1800° F for up to 1 hour to reduce the iron in the ilmenite ore to metallic iron and the calcium sulfate to calcium sulfide; c. magnetically separating the reduced mixture to form a magnetic fraction containing the iron and the TiO 2 content of the ores, and a non-magnetic fraction comprising the calcium sulfide and non-TiO 2 gangue, and segregating the non-magnetic fraction; d. leaching said magnetic fraction with a ferric chloride solution thus dissolving said metallic iron and filtering the leached fraction leaving the TiO 2 -components as a residue; e. dissolving the TiO 2 residue in concentrated sulfuric acid to form a titanyl sulfate solution thereof; f. adding at least one mole equivalent of calcium chloride solution to said titanyl sulfate solution to form a solution of titanyl chloride and a precipitate of insoluble calcium sulfate; g. separating said insoluble calcium sulfate precipitate from said titanyl chloride solution; h. hydrolyzing said titanyl chloride solution by the addition of water and heat, thus precipitating titanium oxide hydrate and liberating gaseous hydrochloric acid; i. calcining said titanium oxide hydrate to form TiO 2 in rutile form; j. recycling the liberated hydrochloric acid from (h) to react with the calcium sulfide of the non-magnetic fraction obtained at (c) to form the calcium chloride used in step (f); k. recycling the calcium sulfate precipitate, separated at (h), to mix with fresh ilmenite at (a); l. oxidizing the leached iron-containing solution with an oxygen-containing gas to precipitate iron oxide (Fe 2 O 3 ) from said solution and regenerating ferric chloride solution for use in step (d).