Process for separation of the lanthanides

A liquid-liquid extraction process for the separation of yttrium from terbium comprising:

• a. admixing a mixture of rare earth elements including at least yttrium and terbium and impurities in aqueous solution 1.5 N with sulfuric acid to form an aqueous phase comprising an aqueous solution of rare earth sulfates including at least yttrium sulfate and terbium sulfate;
• b. contacting said aqueous phase with an organic phase comprising an organic solvent which is 1 M in di(2-ethylhexyl) phosphoric acid, said organic solvent being substantially immiscible with water;
• c. maintaining the contact between the aqueous phase and the organic phase for a sufficient time so that substantially all of the yttrium and terbium are extracted into the organic phase;
• d. separating the aqueous phase from the organic phase;
• e. subjecting the separated organic phase of step (d) to a back extraction with an aqueous phase comprising an aqueous solution 2.7 N with sulfuric acid;
• f. regulating the time of contact between the separated organic phase and the back extraction aqueous phase to a period of less than the time to total extraction equilibrium for the phases and between the half time in minutes for the extraction of terbium from the separated organic phase into the back extraction aqueous phase and the half time in minutes for the extraction of yttrium from the separated organic phase into the back extraction aqueous phase;
• and
• g. separating the separated organic phase from the back extraction aqueous phase.

A liquid-liquid extraction process for the separation of yttrium from terbium comprising:

• a. admixing a mixture of rare earth elements including at least yttrium and terbium and impurities in aqueous solution 1.5 N with sulfuric acid to form an aqueous phase comprising an aqueous solution of rare earth sulfates including at least yttrium sulfate and terbium sulfate;
• b. contacting said aqueous phase with an organic phase comprising on organic solvent which is 1 M in di(2-ethylhexyl) phosphoric acid, said organic solvent being substantially immiscible with water;
• c. maintaining the contact between the aqueous phase and the organic phase for a sufficient time so that substantially all of the yttrium and terbium are extracted into the organic phase;
• d. separating the aqueous phase from the organic phase;
• e. subjecting the separated organic phase of item (d) to a back extraction with an aqueous phase comprising an aqueous solution 2.7 N with sulfuric acid;
• f. regulating the time of contact between the separated organic phase and the back extraction aqueous phase to a period of six minutes;
• and
• g. separating the separated organic phase from the back extraction aqueous phase.