Separation and Purification of Rare-Earth Elements Based on Electrophoretic Migration (PART II)

Solvent extraction is the most widely used method for separation and purification of rare earth elements, and organic extractants such as di(2-ethylhexyl) phosphoric acid (P204) and di(1-methyl-heptyl) methyl phosphonate (P350) are most commonly used for industrial applications. However, the presence of impurity ions in the feed liquid during extraction can easily emulsify the extractant and affect the quality of rare earth products. Aluminum ion is the most common impurity ion in the feed liquid, and it is an important cause of emulsification of the extractant. In this study, the influence of aluminum ion was investigated on the extraction of light rare earth elements by the P204-P350 system in hydrochloric acid medium. The results show that Al3+ competes with light rare earths in the extraction process, reducing the overall extraction rate. In addition, the Al3+ stripping rate is low and there is continuous accumulation of Al3+ in the organic phase during the stripping process, affecting the extraction efficiency and even causing emulsification. The slope method and infrared detection were utilized to explore the formation of an extraction compound of Al3+ and the extractant P204-P350 that entered the organic phase as AlCl[(HA)2]2P350(o).

Download Full-text

Separation and Purification of Rare Earth Elements by Fractional Crystallization. III. Separation of Cerium Group Elements by Fractional Crystalliz a tion of Double Magnesium Nitrate

The Journal of the Society of Chemical Industry Japan ◽

10.1246/nikkashi1898.66.6_762 ◽

1963 ◽

Vol 66 (6) ◽

pp. 762-765 ◽

Cited By ~ 1

Author(s):

Jiro Shiokawa

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Fractional Crystallization ◽

Magnesium Nitrate ◽

Separation And Purification ◽

Cerium Group

Download Full-text

Studies of the Effect of Crosslinking in the Strongly Basic Anion Exchanger Dowex 1 and the HNO3 Concentration Employed on the Separation of the SmIII–NdIII Pair in the Polar Organic Solvent–H2O–HNO3 System

Adsorption Science & Technology ◽

10.1260/0263617011494105 ◽

2001 ◽

Vol 19 (3) ◽

pp. 219-228

Author(s):

Z. Hubicki ◽

M. Olszak

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Anion Exchanger ◽

High Temperature Superconductors ◽

Ceramic Materials ◽

Modern Technology ◽

Separation And Purification ◽

Structural Stabilization ◽

Component Content ◽

Dowex 1

Because of their specific structure, rare earth elements are used for the modification or structural stabilization of many metallic or ceramic materials employed in modern technology and also in the metallic form, i.e. in alloys and compounds with unique properties. Industrial demand for rare earth metals has increased lately due to their new application possibilities, e.g. in supermagnets of the Nd–Fe–B type or in ceramic high-temperature superconductors. Equally, the application of rare earth elements in metallurgy, catalysis, ceramics, etc. remains of significant importance. The separation and purification of rare earth elements(III) which occur in groups with similar physicochemical properties involve extremely difficult and complex processes. Ion exchange is one method which enables such separation. This paper presents the results of studies of the influence of the extent of crosslinking in the anion exchanger Dowex 1 and the concentration of nitric acid on the separation of the SmIII–NdIII pair by frontal analysis in 90% v/v CH3COCH3– or the CH3OH–10% v/v × M HNO3 systems. The most effective results were obtained in the 90% v/v CH3OH–10% v/v 7 M HNO3 system employing the anion exchanger Dowex 1 × 4 allowing 0.11 kg samarium(III) to be purified on 1 dm3 ion exchanger in the nitrate form and leading to a decrease in the micro-component content to a value below 10−3%.

Download Full-text