Processing titaniferous iron ores for the recovery of aluminum, chromium, iron, titanium and vanadium

Claim 1

A PROCESS FOR TREATING TITANIFEROUS IRON ORE OR CONCENTRATE HAVING A TOTAL IRON CONTENT OF AT LEAST 40% AND A TITANIUM DIOXIDE CONTENT OF LESS THAN 25% WHICH COMPRISES A. ROASTING THE FINELY DIVIDED TITANIFEROUS IRON ORE OR CONCENTRATE IN ANN OXIDIZING ATMOSPHERE AND IN THE PRESENCE OF A ROASTING AGENT MADE UP OF A MIXTURE OF (1) A SODIUM OXIDE FORMING COMPOUND AND (2) AN ALKALINE EARTH METAL OXIDE COMPOUND SELECTED FROM CALCIUM OXIDE, MAGNESIUM OXIDE, A CALCIUM OXIDE FORMING COMPOUND, A MAGNESIUM OXIDE FORMING COMPOUND AND MIXTURE THEREOF, THE AMOUNT OF SODIUM OXIDE OR SODIUM OXIDE FORMING COMPOUND BEING AT LEAST THE STOICHIOMETRIC AMOUNT EXPRESSED AS SODIUM OXIDE AND CALCULATED IN ACCORDANCE WITH THE FORMULA: NA2O(MOLES) =2 $ CR2O3(MOLES) + 3 $ V2O5(MOLES) + AL2O3(MOLES) AND THE AMOUNT OF THE SECOND OXIDE FORMING COMPOUND OF THE ROASTING AGENT BEING AT LEAST THE STOICHIOMETRIC AMOUNT EXPRESSED AS CALCIUM OXIDE OR MAGNESIUM OXIDE CALCULATED IN ACCORDANCE WITH THE FORMULA: CAO OR MGO(MOLES) =2 $ SIO2(MOLES) + TIO2(MOLES) - (CAO + MGO) (MOLES IN THE ORE OR CONCENTRATE) B. LEACHING THE ROAST WITH AN AQUEOUS SOLUTION OF 5 TO 75 GR/L OF SODIUM CARBONATE AND 2 TO 10 GR/L OF SODIUM HYDROXIDE; C. AND SEPARATING THE SOLID CONTAINING THE RESIDUE FROM THE CHROMATE, ALUMINATE AND VANADATE CONTAINING SOLUTION.