Institute of High Technologies, Kazatomprom, Almaty, Kazakhstan:
M. P. Kopbaeva, Deputy Research Director, Candidate of Chemical Sciences
E. N. Panova, Head of Department, Candidate of Chemical Sciences, e.panova@iht.kz
N. A. Prinzin, Senior Researcher
E. M. Karmanov, Senior Researcher

In focus are the regular patterns in the behavior of marketable desorbent for uranium under peroxide precipitation. It is found that ferrum and phosphor go from pregnant solution to marketable desorbent. The remainder insoluble in nitric acid forms as desorbing solution is prepared from mother liquid containing polymeric compounds of silicic acid. The article shows that the remainder insoluble in nitric acid is a mixture of metasilicic acid gel, soddyite and epidote. It is found that ferrum, phosphorus and impurities that form the nitric acid-insoluble remainder settle down from the marketable desorbent at the stage of preliminary neutralization to pH = 4. In order that uranium peroxide conforms with the standards ASTM С967-08, it is necessary to settle and fi lter the pregnant solution before peroxide precipitation. The hydrolytic settle, after it has been washed and dissolved in acid, is to be added to the pregnant solution, which will bring uranium contained in the remainder back to the stage of adsorption. It is recommended to use demineralized water to prepare stripping solution, which will allow zero pollution of uranium peroxide with silica and calcium and zero loss of uranium in the form insoluble in nitric acid. The optimized mode experimentation on peroxide precipitation of uranium from marketable desorbent has allowed ferrum removal from the marketable desorbent by 100%, silica–by 86.54% and phosphorus—by 42.86%. The analysis of the resultant uranium peroxide yields complete consistency with ASTM C967-08 standards: ferrum and remainder insoluble in nitric acid are totally absent, and phosphorus content is 0.012%, i.e. 8 times below the threshold specified by STM C967-08.

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