Separation of individual rare earths elements by association of homogeneous precipitation and ion exchange techniques

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1973

OSTI ID:4329381

Umeda, K

This work was developed at the Atomic Energy Institute's Chemical Engineering Department, by associating both fractional homogeneous precipitation and ion exchange techniques for the separation of Ce, Ni, Pr, Sm and La as individual rare earths from their mixed chlorides supplied by Administracgo da Producao da Monazirt, Sao Paulo. Cerium was first separated from Nd, Pr, Sm, La and other yttrium group rare eahhs by precipitation of Ce-IV hydroxide with urea and hydrogen peroxide as oxidant. The same technique but without hydrogen peroxide was used for the enrichment of Nd, Pr and Sm in subsequent precipitations; La was kept in the last filtrate. Experimental results showed that the precipitation is very efficient since the urea hydrolysis is easily controlled, allowing the elimination of practically all cerium and about all lanthanum, both elements being the major components of the monazite; their separation making easy later fractionation on ion exchange columns. The separation of individual Nd, Pr, Sm and La was made by two exchange (Dowex-50 W, X-8) columns, Cu/sup 2+/ as retaining ion and EDTA-NH/sub 4/ solution buffered with acetic acid as eluent. Thc application of this technique has made possible the separation of individual rare earths, avoiding the precipitation inside the columns owing to acidity changes. Copper was recovered by precipitation of Cu/ sub 2/S through thiourea hydrolysis in the Cu-EDTA complex solutions. The associated techniques allowed the obtention of Nd, Pr and La fractions approximately 99% pure and cerium about 95% pure. (INIS)

• Research Organization: Sao Paulo Univ. (Brazil). Escola Politecnica
• NSA Number: NSA-29-029053
• OSTI ID: 4329381
• Report Number(s): INIS-mf--1224
• Country of Publication: Brazil
• Language: Portuguese

Related Subjects

*CERIUM-- PRECIPITATION
*LANTHANUM-- ION EXCHANGE
*NEODYMIUM-- ION EXCHANGE
*PRASEODYMIUM-- ION EXCHANGE
*SAMARIUM-- ION EXCHANGE
HYDROGEN PEROXIDE
N40140* --Chemistry--Separation Procedures
RARE EARTHS
SEPARATION PROCESSES
UREA