STUDY OF EXTRACTION PROPERTIES OF METHYL-PHOSPHONIC DIETHERS IN TERMS OF EXTRACTION AND PURIFICATION OF URANIUM OBTAINED FROM PROCESS SAMPLES USING THE EXTRACTION CHROMATOGRAPHY METHOD
Extraction properties of methyl-phosphonic diisoamyl (DIAMPh) and di(2-ethylhexyl) (DEHMPh) ethers were studied using model and real uranium-containing solutions. Uranium was extracted and purified with the help of the extraction chromatography method through the use of silica gel and fluorocarbon polymer as carriers. It was shown that DIAMPh is not appropriate for the selected method due to its low adhesion to surface of the inert carrier. At the same time DEHMPh, when its concentration is 200 mg per 1 g of the carrier or more, quantitatively extracts uranium from nitro-acid media. The extragent efficiently purifies uranium from plutonium and fission products that allows decreasing radioactivity of the output solutions on the average by 10000 times. No significant purification factor reduction is observed in chromatographic columns filled with DEHMPh - sorbent during at least 15 cycles of U extraction. The studies demonstrated that extraction properties of DEHMPh are similar to those of the mixture of methyl-phosphonic ethers (MEMPh) used at Plant 235. Since production of MEMPh has been ceased in Russia, DEHMPh can be used instead of it in analytical methods including a stage of extraction-chromatographic U extraction.