Monday, October 9, 2017

The extraction of rare earths

I really enjoyed this letter to the editor about the initial discovery of rare earths at the Ames Laboratory: 
The recent article about rare earths (C&EN, Aug. 28, page 30) reminded me of my work at Ames during the early 1950s. From 1951 to 1953, I worked for Frank Spedding, who was director of both Iowa State University’s Institute for Atomic Research and the Ames Laboratory of the Atomic Energy Commission (now the U.S. Department of Energy). His earlier work in support of the Manhattan Project is well-known. In addition, his interest in the chemistry of rare earths led to the development of ion-exchange procedures that made it possible for us to produce some of the first multigram quantities of high-purity rare-earth oxides by a relatively simple process. 
Our first work was with 1-inch-diameter, 48-inch-long [2.54-cm-diameter, 121.92-cm-long] glass columns filled with Dowex-50 resin. The distribution of the resin in the columns and the elution rates required careful control to maintain horizontal boundaries between the rare earths as they moved down the column. 
Initially, the eluant was collected at a drops-per-minute rate into 10-mL flasks, and one of us was in attendance 24 hours a day to change flasks and to make sure no problems occurred. When it was established that high-purity material was being obtained by the procedure, some was converted into metal by Harley Wilhelm in the lab’s metallurgy facility. By 1953 the columns had grown to 8 inches [20.32 cm] in diameter and 10 feet [3.05 meters] in length, and proportionally more rare earths were being produced. 
Even then we had no sense of the elements’ future importance, and it is interesting to read of their many applications today. 
(The picture of colored rare earth oxides in the article could also have included erbium, which is pink, as I recall.) 
Jack L. Evans
Sun Lakes, Ariz.
It's kinda funny and weird to me that fraction collectors were not available, even in the early 1950s. Nevertheless, pretty cool.  

No comments:

Post a Comment