DETERMINATION OF RARE EARTH METALS IN THEIR MIXTURE
A method based on the sorption of rare earth elements (REE) by a Dowex- 50 cationite, subsequent elution of REE with solutions of different pH values, quantitative determination of the separate components by means of oxalate precipitation, and smelting and weighing the residues obtained, is described. Dissolving < 200 mg of the mixture of REE oxides in HCl, sealing the solution in a glass ampule, and activation of REE with a neutron source precede the breaking down of REE. The resulting solution is passed through a small ionite column, REE is introduced into the large column 2 m long and 1 cm in diameter, filled with Dowex50 cationite with a granularity of 0.04 to 0.05 mm, and rinsed with ammonia and with the elutriating solution (ES). The relative rate of elutriation of REE changes by jumps within the limits of the narrow pH interval which occupies a different position for all the elements being studied. By gradually changing the pH of ES, consecutive extraction of the components of the mixture in the series of increasing ion radii is achieved. In the proposed method of stage chromatography, elutriation is carried out at 76 deg C and the ES used in this method consists of 1 M solutions of lactic acid with the addition of 0.1 mole/l of phenol, the pH of which is controlled by the passage of gaseous NH/sub 3/. At first ES with pH 3.00 is passed through the column at the rate of 5 ml/min and the activity of the elutriate is continuously measured. Upon attaining the maximum activity in the last element being extracted by the given ES, one begins to pass through the next ES with a higher pH value. Simultaneously the receiver for collecting the fractions of the elutriate is changed. The first ES with pH 3.00 extracts Sc, Lu, Yb; the 2nd (pH 3.05) extracts Tm, Er, Ho; the 3rd (pH 3.10) extracts Y, Dr, Tb; the 4th (pH 3.15) extracts Cd, Eu; the 5th (pH 3.25) extracts Sm (Pm); the 6th (pH 3.30) extracts Nd, Pr; the 7th (pH 3.44) extracts Ce; and the 8th (pH 3.50) extracts La. Each fraction of the elutriate is examined by x-ray method for REE content and then used for separation by oxalate precipitation of the elements being determined. Fractions of similar composition are united prior to the addition of the precipitating agent. The precipitate is set out for 24 hours, then filtered and flushed with 0.5 M H/sub 2/SO/sub 4/ solution, saturated with oxalic acid. Then it is annealed at 1000 deg C and weighed. The method is used for quantitative analysis of different mixtures of REE. In the opinion of the authors this method can be utilized for determination of the ions of 3-valence actinides in their mixtures.
- Research Organization:
- Hungarian Academy of Sciences, Budapest
- NSA Number:
- NSA-14-012591
- OSTI ID:
- 4193997
- Journal Information:
- Acta Chimica Academiae Scientiarum Hungaricae (Hungary), Journal Name: Acta Chimica Academiae Scientiarum Hungaricae (Hungary) Vol. Vol: 7; ISSN ACASA
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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Related Subjects
ACTINIDES
ACTIVATION
AMMONIA
ANNEALING
BREAKDOWN
CADMIUM
CERIUM
CHEMISTRY
CHROMATOGRAPHY
DYSPROSIUM
ERBIUM
EUROPIUM
EXTRACTION COLUMNS
FILTERS
HOLMIUM
HYDROCHLORIC ACID
ION EXCHANGE MATERIALS
IONS
LANTHANUM
LUTETIUM
MELTING
MIXING
NEODYMIUM
NEUTRON SOURCES
ORGANIC ACIDS
OXALATES
OXALIC ACID
PHENOLS
PRASEODYMIUM
PRECIPITATION
PROMETHIUM
QUALITATIVE ANALYSIS
QUANTITATIVE ANALYSIS
RARE EARTHS
RESIDUES
SAMARIUM
SCANDIUM
SEPARATION PROCESSES
SOLUTIONS
SOLVENTS
SULFURIC ACID
TEMPERATURE
TERBIUM
THULIUM
X RADIATION
YTTERBIUM
YTTRIUM