A method of recovering titanium dioxide from a raw material additionally
containing aluminium includes the steps of grinding the titanium dioxide
raw material, reacting the particulate raw feed material with sulphuric
acid under specified conditions, digesting and filtering the resultant
cake material containing titanyl sulphate, if present, treating the
solution to remove calcium and/or iron, precipitating out the aluminium
as aluminium ammonium sulphate, hydrolysing the remaining titanyl
sulphate solution and, after washing the hydrolysate, calcining the
hydrolysate to produce titanium dioxide.