Process for the synthesis of a mixed peroxide or hydroxo-peroxide of an actinyl and of at least one doubly, triply or quadruply charged metal cation, mixed peroxide or hydroxo-peroxide thus obtained and uses thereof
A process is described for synthesizing a mixed peroxide or hydroxo-peroxide of an actinyl and at least one cation X 1 , wherein the actinyl is a uranyl or neptunyl and the at least one cation X 1 is a di-, tri- or tetra-charged metal cation. This process includes the reaction in a solvent of a salt of the at least one cation X 1 with a compound C 2 selected from mixed peroxides and hydroxo-peroxides of the actinyl and of at least one singly charged cation X 2 , whereby compound C 2 is converted to the peroxide or hydroxo-peroxide by replacement of the at least one cation X 2 by said at least one cation X 1 . Also disclosed is a process for synthesizing a mixed oxide of an actinide selected from uranium and neptunium, and of at least one metal able to form a di-, tri- or tetra-charged cation, which implements the preceding synthesis process. The disclosure further relates to a mixed peroxide or hydroxo-peroxide of an actinyl and of at least one di-, tri- or tetra-charged metal cation, and the use thereof for the preparation of a mixed oxide of an actinide and of at least this metal.
1. A process for synthesizing a compound C 1 selected from the group consisting of mixed peroxides and hydroxo-peroxides of an actinyl and of at least one cation X 1 , wherein:
the actinyl has formula AnO 2 q+ where An is an actinide selected from the group consisting of uranium and neptunium, and q equals 1 or 2;
the cation X 1 is a doubly, triply or quadruply charged metal cation, wherein the metal differs from An;
which process comprises a reaction in a solvent of a salt of the cation X 1 with a compound C 2 selected from the group consisting of mixed peroxides and hydroxo-peroxides of the actinyl and of at least one singly charged cation X 2 , whereby compound C 2 is converted to compound C 1 by a replacement of the cation X 2 by the cation X 1 .
2. The process of claim 1 , wherein the cation X 1 is a cation of an alkaline-earth metal, a cation of a post-transition metal, a cation of a transition metal, a cation of a lanthanide or a cation of an actinide.
3. The process of claim 2 , wherein the cation X 2 is a cation of an alkaline metal, a cation of a transition metal or a polyatomic cation.
4. The process according to claim 1 , wherein the reaction of the cation X 1 with compound C 2 comprises adding a solution of the salt of the cation X 1 to compound C 2 to obtain a reaction medium, and leaving the reaction medium to stand for sufficient time to obtain the replacement of the cation X 2 by the cation X 1 .
5. The process of claim 4 , wherein the solution of the salt of the cation X 1 is an aqueous solution.
6. The process of claim 1 , further comprising a synthesis of compound C 2 .
7. The process of claim 6 , wherein the synthesis of compound C 2 comprises a reaction of a first aqueous solution comprising a salt of the actinide An with an alkaline second aqueous solution comprising a salt or hydroxide of the cation X 2 and hydrogen peroxide.
8. The process of claim 7 , wherein the synthesis of compound C 2 comprises adding the first solution to the second solution under agitation to obtain a reaction medium and leaving the reaction medium to stand for sufficient time to obtain the formation of compound C 2 .
9. The process of claim 1 , wherein compound C 1 has general formula (I):
(X 1 m+ ) r1 [(AnO 2 q+ ) n (O 2 2− ) p−x (OH − ) 2x ] (2p−qn)− (I)
where:
m equals 2, 3 or 4;
n is an even integer of 2 or higher;
x is an integer of 0 or higher;
p is an integer higher than x; and
n, p and r1 are such that 1.5≤p/n≤2 and 0<r1=(2p−qn)/m.
10. The process of claim 9 , wherein compound C 2 has general formula (II):
(X 2 + ) r2 [(AnO 2 q+ ) n (O 2 2− ) p−x (OH − ) 2x ] (2p−qn)− (II)
where:
0<r2=2p−qn.
11. The process of claim 9 , wherein n is an even integer ranging from 2 to 60.
12. The process of claim 1 , wherein the cation X 1 is a cation of an actinide or lanthanide.
13. The process of claim 1 , wherein the cation X 2 is an ammonium cation.
14. A process for synthesizing a mixed oxide of an actinide An selected from the group consisting of uranium and neptunium, and of at least one metal able to form a doubly, triply or quadruply charged metal cation X 1 , the metal differing from An, which process comprises:
synthesizing a mixed peroxide or hydroxo-peroxide of an actinyl of formula AnO 2 q+ where q equals 1 or 2, and of at least the cation X 1 , the synthesis comprising a reaction in a solvent of a salt of the cation X 1 with a compound C 2 selected from the group consisting of mixed peroxides and hydroxo-peroxides of the actinyl and of at least one singly charged cation X 2 , whereby compound C 2 is converted to compound C 1 by a replacement of the cation X 2 by the cation X 1 ; and
calcining the mixed peroxide or hydroxo-peroxide thus synthesized.
15. A mixed peroxide or hydroxo-peroxide of an actinyl and of at least one cation X 1 , wherein:
the actinyl has formula AnO 2 q+ where An is an actinide selected from the group consisting of uranium and neptunium, and q equals 1 or 2;
the cation X 1 is a doubly, triply or quadruply charged metal cation, wherein the metal differs from An;
the peroxide or hydroxo-peroxide has following general formula (I):
(X 1 m+ ) r1 [(AnO 2 q+ ) n (O 2 2− ) p−x (OH − ) 2x ] (2p−qn)− (I)
where:
m equals 2, 3 or 4;
n is an even integer of 2 or higher;
x is an integer of 0 or higher;
p is an integer higher than x; and
n, p and r1 are such that 1.5≤p/n≤2 and 0<r1=(2p−qn)/m.
16. The peroxide or hydroxo-peroxide of claim 15 , wherein n is an even integer ranging from 2 to 60.
17. The peroxide or hydroxo-peroxide of claim 15 , wherein the cation X 1 is a cation of an actinide or lanthanide.
18. The process of claim 10 , wherein n is an even integer ranging from 2 to 60.