Investigation of adsorption of rare earths and a few other elements to an anion-exchange resin from mixed solvents containing lactic acid shows that the lanthanides are absorbed more strongly than from the alpha-hydroxyisobutryric acid system, but with less separation between adjacent members of the series

Faris, J. P.

English

NASA Technical Reports Server

September 1969
	 Brief 69-10377 
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the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Separation of the Rare Earths by Anion-Exchange

in the Presence of Lactic Acid 
S
Adsorption of the rare earths and a few other ele-
ments to an anion-exchange resin, from mixed sol-
vents containing lactic acid, has been investigated. 
Tests showed that the lanthanides were absorbed 
more strongly than from the a-hydroxyisobutyric 
acid system, but with less separation between ad-
jacent members of the series. 
Earlier studies had shown that the rare earths 
could be separated by anion-exchange in a lactate 
medium. Application of the system was limited, how-
ever, because of the low adsorption from aqueous 
solution. Adsorption characteristics of the rare 
earths in various water-solvent mixtures containing 
cv-hydroxyisobutyric acid had been reported. Now 
reported (1) are results of a similar investigation 
with lactic acid as the complexing agent. 
A stock solution of pure lactic acid was prepared. 
An aqueous solution of the commercial product was 
neutralized with NaOH and passed through a column 
of cation-exchanger in the hydrogen form. Adsorp-
tion of the rare earths from various solvent mixtures 
was determined at room temperature (about 23CC) by 
column elution with AG-Dowex 1 x4, 100-200-mesh, 
anion-exchange resin used in the lactate form. Micro-
gram amounts of a rare-earth mixture were added to 
an equilibrated column and then eluted with the 
appropriate solvent mixture. The elution of each ele-
ment was determined by emission-spectrographic 
analysis of efficient fractions. 
Distribution coefficients were calculated from the 
expression Kd = VIM, where V is the volume (milli-
liters) that had passed through the column at the elu-
tion-curve peak (corrected for the first volume- of 
interstitial liquid displaced), and M is the mass of 
resin in grams. 
Results showed that adsorption of the rare earths 
from lactic acid solutions was greater than that from 
a-hydroxyisobutyric acid. Experimental results, show-
ing the variation of distribution coefficients with 
proportion of aqueous content in methanol mixtures, 
are summarized. 
Distribution coefficients generally increased with 
the concentration of lactic acid in a solvent mixture, 
but separation factors between all elements save La 
were not appreciably affected. A comparison of rare-
earth adsorption, in nine different solvents containing 
a constant proportion of water and lactic acid, is 
given. Separation of adjacent rare earths was some-
what better in methanol solution than in any of the 
other solvents tested. 
Strontium and barium were not adsorbed from any 
solvent mixture and could be readily separated from 
the rare earths. Ferric iron was strongly adsorbed 
from aqueous solutions of lactic acid. 
Reference: 
I. J. P. Fans, "Separation of the rare earths by anion 
exchange in water-solvent mixtures in the presence 
of lactic acid" (Argonne National Laboratory, Sept. 
1967). 
Notes: 
1. This information may interest producers of rare-
earth elements.
(continued overleaf) 
This document was prepared under the sponsorship of the Atomic	 liability resulting from the use of the information contained in this 
Energy Commission and/or the National Aeronautics and Space	 document, or warrants that the use of any information, apparatus, 
Administration. Neither the United States Government nor any per- 	 method, or process disclosed in this document may not infringe pri-
son acting on behalf of the United States Government assumes any 	 vately owned rights.
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2. Inquiries concerning this innovation may be di-	 Patent status: 
rected to:	 - 
Office of Industrial Cooperation 
Argonne National Laboratory 
9700 South Cass Avenue 
Argonne, Illinois 60439 
Reference: B69-10377
Source: J. P. Fans
Chemistry Division
(ARG- 10436)
Inquiries concerning rights for commercial use of 
this innovation may be made to: 
Mr. George H. Lee, Chief 
Chicago Patent Group 
U.S. Atomic Energy Commission 
Chicago Operations Office 
9800 South Cass Avenue 
Argonne, Illinois 60439 
Brief 69-10377	 Category 03


Separation of the rare earths by anion-exchange in the presence of lactic acid

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