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Thesis submitted to Universite de Paris, France. A study was made of
the part taken by organic substances in ores that contain urarium in a
disseminated form, without mineralization, considering the reaction between
uranium and humus. Humic acids are extracted from the peat by ammonia. By the
fact of their ability to cationic exchange, these form humates with metal
cations; monovalent humates, normally soluble in water, can become insoluble
after treatment of humic acids with methanol. The polyvalent humates are
insoluble in water, especialiy humates of U (IV) and uranyl U (VI). Action of
Li, Na, K, Mg, and Ca uranylcarbonates solutions on the humic acids results in
the formation of humates contairing uranyl and the other cation. About 100 g of
humic acids gave a fixation of no more than 38 g of uranium as uranyl. In
contact with uraniferous weakly concentrated solutions, they fixed 4 to 8 g
according to pH, with a yield in the extraction greater than 95%. The action of
a sodium humate solution on a humate of uranyl gave a solution containing a
soluble sodium and uranyl humate. The solution was precipitated at various
degrees by the polyvalent cations and insoluble humic substances. In all cases,
the fixation of urarium with such prepared humic acids corresponds to a
chemisorption of uranyl cations. (auth)
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