The effectiveness of ion exchange resins in separating uranium and thorium from rare earth elements in acidic aqueous sulfate media. Part 1. Anionic and cationic resins

Rare-earth elements (REEs) are involved in most high technology devices and have become critical for many countries. The progress of processes for the extraction and recovery of REEs is therefore essential. Liquid–solid extraction methods are an attractive alternative to the conventional solvent extraction process used for the separation and/or purification of REEs. For this purpose, a solid-phase extraction system was investigated for the extraction and valorization of REEs. Ion-exchange resins were synthesized involving the condensation of terephthalaldehyde with resorcinol under alkaline conditions. The terephthalaldehyde, which is a non-hazardous aromatic dialdehyde, was used as an alternative to formaldehyde that is toxic and traditionally involved to prepare phenolic ion-exchange resins. The resulting formaldehyde-free resole-type phenolic resins were characterized and their ion-exchange capacity was investigated in regard to the extraction of rare-earth elements. We herein present a promising formaldehyde and phenol-free as a potential candidate for solid–liquid extraction REE with a capacity higher than 50 mg/g and the possibility to back-extract the REEs by a striping step using a 2 M HNO3 solution.

Download Full-text

Selective Extraction of Rare Earth Elements from Phosphoric Acid by Ion Exchange Resins

Metals ◽

10.3390/met8090682 ◽

2018 ◽

Vol 8 (9) ◽

pp. 682 ◽

Cited By ~ 12

Author(s):

Xavier Hérès ◽

Vincent Blet ◽

Patricia Di Natale ◽

Abla Ouaattou ◽

Hamid Mazouz ◽

...

Keyword(s):

Rare Earth ◽

Ion Exchange ◽

Phosphoric Acid ◽

Rare Earth Elements ◽

Moving Boundary ◽

Cost Effective ◽

Selective Extraction ◽

Ion Exchange Resins ◽

Maximum Sorption Capacity ◽

Exchange Resins

Rare earth elements (REE) are present at low concentrations (hundreds of ppm) in phosphoric acid solutions produced by the leaching of phosphate ores by sulfuric acid. The strongly acidic and complexing nature of this medium, as well as the presence of metallic impurities (including iron and uranium), require the development of a particularly cost effective process for the selective recovery of REE. Compared to the classical but costly solvent extraction, liquid-solid extraction using commercial chelating ion exchange resins could be an interesting alternative. Among the different resins tested in this paper (Tulsion CH-93, Purolite S940, Amberlite IRC-747, Lewatit TP-260, Lewatit VP OC 1026, Monophos, Diphonix,) the aminophosphonic IRC-747, and aminomethylphosphonic TP-260 are the most promising. Both of them present similar performances in terms of maximum sorption capacity estimated to be 1.8 meq/g dry resin and in adsorption kinetics, which appears to be best explained by a moving boundary model controlled by particle diffusion.

Download Full-text

Removal of Impurities from Saturated Ion-Exchange Resins by Frontal-Gradient Purification in Schemes for Recovery of Nonferrous, Rare, and Rare Earth Metals

Theoretical Foundations of Chemical Engineering ◽

10.1134/s0040579518050111 ◽

2018 ◽

Vol 52 (5) ◽

pp. 920-927

Author(s):

E. I. Gedgagov ◽

S. V. Zakhar’yan ◽

O. M. Sinyanskaya ◽

D. V. Zakhar’yan

Keyword(s):

Rare Earth ◽

Ion Exchange ◽

Rare Earth Metals ◽

Ion Exchange Resins ◽

Removal Of Impurities ◽

Exchange Resins

Download Full-text

Rare Earth Element Preconcentration from Various Primary and Secondary Sources by Polymeric Ion Exchange Resins

Separation and Purification Reviews ◽

10.1080/15422119.2021.1993255 ◽

2021 ◽

pp. 1-16

Author(s):

Vladimir Rychkov ◽

Evgeny Kirillov ◽

Sergey Kirillov ◽

Grigory Bunkov ◽

Maxim Botalov ◽

...

Keyword(s):

Rare Earth ◽

Ion Exchange ◽

Rare Earth Element ◽

Earth Element ◽

Ion Exchange Resins ◽

Secondary Sources ◽

Exchange Resins

Download Full-text

Rare Earth Metals Leaching from Coal Ash and Theirs Concentration

Safety in Technosphere ◽

10.12737/19023 ◽

2016 ◽

Vol 5 (1) ◽

pp. 48-55

Author(s):

Сеник ◽

E. Senik ◽

Виноградов ◽

M. Vinogradov ◽

Таранов ◽

...

Keyword(s):

Rare Earth ◽

Ion Exchange ◽

Rare Earth Metals ◽

Experimental Studies ◽

Cation Exchange Resin ◽

Acid Leaching ◽

Coal Ash ◽

Flow Diagram ◽

Ion Exchange Resins ◽

Exchange Resins

Problems related to rare earth metals leaching from coal ash and theirs ion-exchange concentration from sulfuric solutions, in particular the characteristics of scandium, yttrium and lanthanum sorption by different ion exchange resins have been considered in this work. It has been shown that the best way to leach rare earth metals from coal ash is a complex acid and biological treatment of ash waste. Kinetics related to the process of scandium, yttrium and lanthanum acid leaching from ash and slag waste of CHPP in Kumertau has been investigated. Subsequent metal solutions concentration was achieved using ion exchange resins. The results of experimental studies related to the processes of rare-earth metals (in particularly scandium) ion exchange concentration by cation exchange resin in the Naform PC-100 have been presented, as well as the results of experimental studies related to rare earth metals (scandium including) sedimentation process, using special sedimentators. Dependences of rare earth metals (in particular scandium) sedimentation efficiency against pH value have been constructed, and recommendations for pH values, that are optimal for rare earth metals sedimentation, have been given. Based on obtained experimental results it was created and tested an experimental laboratory prototype of plant for rare earth metals (scandium, yttrium and lanthanum including) extraction from located near Moscow brown coal basin’s slag heaps, and from ash dumps of Russian Federation’s energy enterprises. This plant’s process flow diagram as well as its operation description has been presented. The created plant was tested in modes previously fulfilled in laboratory conditions. At the same time, carried out integrated exploration have showed the prospects for implementation of developed technical solutions for processing of ash dumps of Russian Federation’s various energy enterprises.

Download Full-text

Embedding Procedure for Water Swollen Samples

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010006951x ◽

1970 ◽

Vol 28 ◽

pp. 504-505

Author(s):

Ann M. Thomas ◽

Virginia Shemeley

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Ion Exchange ◽

Structural Changes ◽

Cross Linking ◽

Ion Exchange Resins ◽

Transmission Electron ◽

First Pass ◽

Exchange Resins

Those samples which swell rapidly when exposed to water are, at best, difficult to section for transmission electron microscopy. Some materials literally burst out of the embedding block with the first pass by the knife, and even the most rapid cutting cycle produces sections of limited value. Many ion exchange resins swell in water; some undergo irreversible structural changes when dried. We developed our embedding procedure to handle this type of sample, but it should be applicable to many materials that present similar sectioning difficulties.The purpose of our embedding procedure is to build up a cross-linking network throughout the sample, while it is in a water swollen state. Our procedure was suggested to us by the work of Rosenberg, where he mentioned the formation of a tridimensional structure by the polymerization of the GMA biproduct, triglycol dimethacrylate.

Download Full-text

Applications of Ion Exchange Resin in Oral Drug Delivery Systems

International Journal of Drug Delivery Technology ◽

10.25258/ijddt.v7i03.9556 ◽

2017 ◽

Vol 7 (03) ◽

Author(s):

Kathpalia Harsha ◽

Das Sukanya

Keyword(s):

Drug Delivery ◽

Ion Exchange ◽

Drug Delivery Systems ◽

Oral Drug Delivery ◽

Physical Stability ◽

Delivery Systems ◽

Oral Drug ◽

Ion Exchange Resins ◽

Exchange Resins ◽

Oral Drug Delivery Systems

Ion Exchange Resins (IER) are insoluble polymers having styrene divinylbenzene copolymer backbone that contain acidic or basic functional groups and have the ability to exchange counter ions with the surrounding aqueous solutions. From the past many years they have been widely used for purification and softening of water and in chromatographic columns, however recently their use in pharmaceutical industry has gained considerable importance. Due to the physical stability and inert nature of the resins, they can be used as a versatile vehicle to design several modified release dosage forms The ionizable drug is complexed with the resin owing to the property of ion exchange. This resin complex dissociatesin vivo to release the drug. Based on the dissociation strength of the drug from the drug resin complex, various release patterns can be achieved. Many formulation glitches can be circumvented using ion exchange resins such as bitter taste and deliquescence. These resins also aid in enhancing disintegrationand stability of formulation. This review focuses on different types of ion exchange resins, their preparation methods, chemistry, properties, incompatibilities and their application in various oral drug delivery systems as well as highlighting their use as therapeutic agents.

Download Full-text