Selective separation of rare earths and impurities from ilmenite ore by addition of K+ and Al3+ ions

A new technique for the selective separation of rare earth oxides and impurities from lower grade titaniferous ores has been developed. The process includes roasting the ore with alkali followed by aqueous leaching which liberates 80% of rare earth oxides from the mineral matrix. The removal of rare earth oxides from ilmenite ore was closely linked with additions of aluminium and potassium ions. Both the cations appear to generate lattice strains within the ilmenite structure which leads to breaking of the lattice and separation of rare earth oxides. The influence of both K+ and Al3+ cations on ilmenite was similar but the mechanism of the reaction was found to be different which we have explained on the basis of crystal structure and ionic radius.