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Reverse precipitation of ammonium diuranate from a solution of uranyl sulfate: decontamination of the sulfate ion. Precipitacao reversa de diuranato de amonio a partir de solucoes de sulfato de uranilo: descontaminacao do ion sulfato (in Portuguese)

Technical Report ·
OSTI ID:4478700
This paper describes a technique for the production of nuclear grade ammonium diuranate (ADU) using uranyl sulfate solutions obtained as eluate from the ion exchange (strong cationic resin) purification of uranium, by precipitation with NH{sub 3} gas. The precipitation of ADU by direct introduction of NH{sub 3} gas into acid uranyl sulfate solution has as consequence a high coprecipitation of sulfate ion, reaching ratios as high as 10 to 14% SO{sub 4}/ADU. To overcome this serious inconvenience, the reverse order of addition of reagents was studied, the ADU precipitation being done in such a way that the pH of the mixture was kept higher than 6 during the whole precipitation. This modification, in conjunction with the adjustment of other precipitation parameters, like temperature, precipitation time, aging time, concentration of uranium in uranyl sulfate and pH, allowed a sucessful precipitation of ADU with low sulfate content. The technique was applied at pilot plant scale, using batch and continuous precipitation, in both cases the obtained ADU was low in sulfate.
Research Organization:
Instituto de Energia Atomica, Sao Paulo (Brazil). Divisao de Engenharia Quimica
NSA Number:
NSA-28-007990
OSTI ID:
4478700
Report Number(s):
IEA--278
Country of Publication:
Brazil
Language:
Portuguese