Spectrophotometric Determination of Yttrium and Rare Earths in Cast Steels

A method for the quantitative spectrophotometric determination of yttrium and rare earths in cast steels was developed. The proposed method consists of the separation of yttrium or rare earth as fluoride from large quantities of iron by coprecipitation with thorium from a solution containing ammonium fluoride.'ihe rare earth is further purified by a second coprecipitation using thorium oxalate as the carrier. The thorium is then separated by anion exchange and yttrium or rare earth determined spectrophometrically using the color forming reagent, arsenazo. Six to 12 determinations may be conveniently carried out simultaneously in l2 to l4 hr. The method appears to be applicable to many other steels where interfering ions would have soluble fluorides and oxalates. (P.C.H.)