Process for the purification of yttrium by solvent extraction

Claim 1

A process for the purification of yttrium which comprises forming a feed solution consisting essentially of an aqueous solution of crude yttrium and heavy rare earth elements, forming a scrub solution consisting essentially of an aqueous solution of ammonium thiocyanate, forming a solvent consisting essentially of triakylphosphine oxide or triarylphosphine oxide and quaternary ammonium salt having cyclohexyl radicals, straight chain alkyl radicals and at least one methyl radical but containing no alkyl radIcal, introducing said solvent solution into one end of an extraction zone while introducing said scrub solution into an opposite end of said extraction zone to effect countercurrent contacting of said solutions, introducing said feed solution into the extraction zone and continuing contacting said solutions to extract heavy rare earth elements from the feed solution and into said solvent solution and recovering purified yttrium remaining in the aqueous solution.