REDUCTION OF IRON IN TITANIUM ORE

摘要

1485589 Rutile TiO 2 BAYER AG 24 Jan 1975 [25 Jan 1974] 3144/75 Heading C1N A synthetic rutile is obtained from Ti and Fe containing ores, optionally preoxidized at temperatures in the range of 500-1200‹ C., by reducing the FeIII into FeII with a gaseous reducing agent at 850-1100‹ C. and leaching the reduced ore to remove the iron values and calcining the residue, wherein the reducing gas contains H 2 and steam and optionally at least one of CO and CO 2 and a molar ratio of H 2 + CO :H 2 O + CO 2 of 0À36-1À8 is maintained during the reduction. The reducing gases may be hydrogen-water mixtures, partly burnt natural gas or partly burnt gaseous or liquid hydrocarbons. When the latter are used 55-80% of the quantity of oxygen required for complete combustion is used for the partial combustion. Steam may also be added during the partial combustion. The reducing agents may be diluted with inert gases. The reduction is preferably performed at 950-1100‹ C. with a H 2 :H 2 O molar ratio of 1À25-1À8 or a H 2 +CO: H 2 O+CO 2 ratio of 0À65 to 1À5. The reduced ore is suitably leached with a mineral acid, preferably 17-22% HCl in a 30-70% stoichiometric excess for 2-5 hours. The reduction and/or the leaching may be carried out in fluidized bed apparatus. The leach residue is preferably calcined at 750-1100‹ C.