Development of Axionit selective ion exchange resins for recovery of rare-earth elements and actinide

In the recovery and separation of various elements, including REE and actinides, sorption technologies are widely used. Thus, for the recovery and refining of Pu(IV), vinylpyridine anion exchanger resins are most often used. In Russia vinylpyridine anion exchange resin VP-1Ap is used to recovery uranium and plutonium. This resin production has been stopped for a number of reasons. To meet the needs of the Russian nuclear industry, Axion has developed a method for the synthesis of the vinyl pyridine anion exchange resin AXIONIT VPA. Studies carried out at the Institute of Physical Chemistry and Electrochemistry of the Russian academy of sciences (IPCE RAS) showed that the physicochemical characteristics of this resin is an analog of VP-1Ap. Due to its sorption characteristics with respect to thorium and plutonium, as well as kinetic parameters, the AXIONIT VPA resin is superior to VP-1Ap. In 2016-2018, Axion produced and delivered a 200kg experimental batch of AXIONIT VPA to one of the enterprises of the nuclear industry in Russia. Sorbents based on extractant N,N,N′,N′‐Tetraoctyl Diglycolamide (TODGA) are widely used for the recovery of ions of radioactive REE and actinides from solutions. The sorbent is produced by impregnating the TODGA on a porous polymeric carrier. AXION has developed and industrialized the production of a TODGA-containing sorbent produced by copolymerization of styrene, divinylbenzene and TODGA (AXIONIT MND) with an extractant content of up to 40% by weight. AXIONIT MND shows a high sorption capacity (0.3-0.4 mmol / g) for Eu³⁺, Th⁴⁺ and UO₂²⁺ ions upon sorption from 1-6 mol/l nitric acid solution. The stripping of the absorbed ions is able to carried out with a 0.01 M solution of HNO3. AXIONIT MND has better sorption and kinetic characteristics as compared to sorbents synthesized by impregnation of the finished polymer matrix. This paper outlines the successful development and industrialization of selective ion exchange resins for effective recovery Pu(IV), most profitable middle and heavy group of REE from nitric-phosphate liquors of fertilizer production, uranium from underground leaching solution. (author)