Study in the Behavior of Several Heavy Elements in Solvents with Hydrofluoric Acid Base.

摘要

Initial goal was the study of two nonaqueous solvents with an HF base, one with an oxidizing character, N(sub 2)O(sub 4)-HF, the other with an acid character, SbF(sub 5)-HF. For the N(sub 2)O(sub 4)-HF mixtures, nitric acid and NO(sub 2+) ions exist in these media, nitric acid is dissociated for concentrations of N(sub 2)O(sup 4)< 10 Moles %, resulting in NO(sub 2+) ions. Results for the dissolution of metals agree with those of Brookhaven. For uranium, the speed did not increase in clear fashion from 60-70/degree/C, but that it obeyed Arrhenius' law between 40 and 115/degree/C. UF(sub 4) was more soluble than ZrF(sub 4). U(IV) passed to U(V) after dissolution. The compound obtained from UF(sub 4) was the same as that obtained from the metal uranium, i.e., NOUF(sub 6). U(VI)appeared to be poorly soluble, the uranium passes into solution particularly at valence 5. For SbF(sub 5)-HF mixtures, the corrosion speeds were much lower than in N(sub 2)O(sub 4)-HF mixtures. For Zr, rates of dissolution are very low, while they are very high with N(sub 2)O(sub 4)-HF. Th is practically not corroded at all. Al was not corroded at all up to 90/degree/C. Only U was dissolved at higher rates than Th and Zr; however, the corrosion speeds at 90/degree/C are equal to those with the N(sub 2)O(sub 4)-HF mixtures at 50/degree/C. This shows that U passed into solution in the trivalent state, and that the product was U(SbF(sub 6))(sub 3). The trivalent uranium compounds were more soluble than the others. Addition of N(sub 2)O(sub 4) to SbF(sub 5)-HF induces acid-base reactions between the NO(sup +) and NO(sub 2)(sup -1) on the one hand, and SbF(sub 6)(sup -1) on the other hand, reactions accompanying the formation of a precipitate, probably a NOSbF(sub 6) and NO(sub 2) SbF(sub 6) mixture. 66 refs., 34 figs., 23 tabs. (ERA citation 13:040558)