Procedure to recover iron, titanium and aluminum from the red daires of bauxita (Machine-translation by Google Translate, not legally binding)

摘要

Procedure for recovering iron, titanium and aluminum from the red grouts of bauxite, which includes treating the red grouts obtained as residue in the production of bauxite according to the Bayer procedure, to obtain valuable iron oxide for metallurgy and to recover titanium oxide, aluminum oxide and oxides of other metals present in the same red sludge, characterized by the following operations: a) preliminary filtration and possibly natural evaporation of the red sludge until obtaining a water content of less than 30% by weight. b) calcination of the red sludge using a hot gas obtained by combustion with air of a solid, liquid or gaseous fuel, c) reduction of calcined red grouts, still hot, with a reducing gas obtained by partial combustion, with air or oxygen, of a fuel in a fluidized bed furnace, so that ferric oxide Fe2O3 is transformed into magnetite Fe3O4, d) cooling of the calcined and reduced red grouts (possibly in combination with a previous heating of the gas used in the reduction) and possibly grinding; e) magnetic separation of the material in wet or dry separators (depending on the cooling system), obtaining a magnetic fraction consisting of concentrated Fe3O4, suitable for the production of high purity pellets for metallurgy. f) recovery of aluminum and titanium oxides from the non-magnetic fraction thus obtained, by pyrogenic synthesis with Na2CO3 and CacO3, leaching of the aluminate thus formed, hydrolysis of the aluminate according to the Bayer procedure and acid attack of the leached residue, with which titanium dioxide is solubilized, g) recovery of the oxides of vanadium, chromium, manganese and other metals contained in the residue that remains after the recovery of Al2O3 and TiO2. (Machine-translation by Google Translate, not legally binding)