GB1313640A - Production of titanium compounds from ores containing oxides of titanium and iron - Google Patents

Abstract

1313640 Titanium oxide; titanium halides; ammonium hexafluorotitanate, Fe 2 O 3 KERALA STATE INDUSTRIAL DEVELOPMENT CORP Ltd 11 March 1970 [26 Sept 1969] 52344/72 Divided out of 1312321 Headings C1A and C1N A titanium ore, such as ilmenite, containing mixed oxides of titanium and iron is treated by fusing the ore with solid KNO 3 or NaNO 3 at 900-1000‹ C., leaching the fused mass with water and filtering it to obtain a residue, said residue then being further treated to obtain either titanium dioxide substantially free from iron contamination, or a halogenated compound of titanium substantially free from iron contamination. The residue may be mixed with charcoal and heated out of contact with air, at 450‹ to 500‹ C. so as to form a magnetic iron oxide which is separated magnetically. In an alternative process the residue is mixed with coke, coal or coal tar and heated at or above 700‹ C. in the absence of air and the resultant mass halogenated to yield titanium halide, e.g. by heating with NH 4 F, NH 4 HF 2 , NH 4 Cl or gaseous Cl 2 , Br 2 , F 2 , or I 2 , optionally with NaCl and I 2 as catalyst. The iron containing material remaining may then be ignited to give ferric oxide. In a further alternative process the residue is powdered and added to a solution of (NH 4 )HF 2 or NH 4 F when the Ti preferentially dissolves and is separated by filtration. The filtrate may be crystallized to give (NH 4 ) 2 TiF 6 , or its pH may be adjusted with ammonia so as to precipitate the hydrated oxide. If desired the filtrate may first be boiled and any iron so precipitated removed by filtration. Alternatively the pH of the filtrate may be adjusted with ammonia to 5À5 to 6 and any iron contaminant deposited as the sulphide by bubbling in H 2 S. The pH of the filtrate may then be raised above 9 with ammonia to precipitate pure hydrated titania which may be calcined. Ammonia may be regenerated from the resultant filtrate by boiling, and the ammonia recycled. The fluoride solution remaining is then used as the ammonium fluoride or bifluoride solution required in the process steps above. In a further embodiment, the residue is dissolved in H 2 SO 4 or HCl and hydrated titania precipitated from the solution. The nitrate required in the process may be regenerated by absorbing nitrogen oxide evolved during the fusion in the aqueous solution of NaOH or KOH obtained by leading the fused product.