Improvements in and relating to the preparation of titanium and iron compounds

摘要

Titaniferous-iron minerals such as ilmenite are treated with aqueous hydrochloric acid say at 50--60 DEG C. to bring both the titanium and iron into solution, or at higher temperatures say at 85--100 DEG C. to bring the iron only into solution and leave the titanium in the residue. Countercurrent working may be used in either case. When using the lower temperature a considerable excess of mineral may initially be employed, and residual mineral be treated with successive charges of hydrochloric acid with successive additions of fresh mineral. When using the higher temperature range a considerable excess of hydrochloric acid may be employed the acid solution obtained being used for preliminary extraction of a further charge of mineral. In carrying out the process, the mineral may be ground and the reaction be effected with agitation ; or small grains or pieces of the mineral may be supported on a permeable false bottom and the acid be percolated through the mass; or the reaction may be effected in closed vessels under pressure. Hydrochloric acid gas may be used to maintain or increase the acid concentration and a small amount of hydrofluoric or sulphuric acid may be added, and a titanous salt be present to reduce the iron to the ferrous state. Iron chloride may be precipitated from the solutions obtained by cooling, refrigeration, or the addition of concentrated hydrochloric acid or hydrochloric acid gas. The mixed solution of iron and titanium chlorides obtained at lower temperatures may be heated to precipitate titanium oxide, whilst the titanium oxide in the residue obtained at higher temperatures may be separated by elutriation. The separated titanium oxide may be further treated as by dissolution in concentrated sulphuric acid. Specification 108,693, [Class 1 (iii)], is referred to.