1. Process for separating lanthanides from one another andor lanthanides from actinides andor actinides from one another andor from other transition metals in an aqueous medium, comprising the steps of:
a) treating of the aqueous medium with at least one ligand selected from the group consisting of ethylenediamine-tetraacetic acid, linear polyamino acids and cyclic polyamino acids;
b) (nano)filtering the aqueous solution treated with the at least one ligand through a membrane, under a transmembrane pressure greater than or equal to 0.01 MPa, so as to collect a retentate enriched in at least one species of lanthanide, actinide or other transition metal which is at least partially complexed with the ligand, and a permeate impoverished in said species; and
c) optionally recovering the ligandspecies complexes to be separated from the retentate, and treating the complexes with at least one decomplexing agent so as to separate the at least one ligand from the species.
2. Process according to claim 1, wherein the at least one ligand is a linear polyamino acid of formula (I):
in which:
a=0 or 1 and b=2 or 3;
c=2 or 3 and d=0 or 1;
p=0 to 3;
p1=1 to 4;
e=0 or 1;
q=1 to 4;
f=2 or 3 and g=0 or 1;
h and i, which are identical or different, are each 1, 2 or 3;
A1, A2 and A3 are identical to or different from one another and correspond to a monovalent acid group selected from the group consisting of:
\u2014COOR, \u2014PO3R\u2032 and \u2014SO3R\u2033,
where R, R\u2032, R\u2033=H or a cation;
the radicals R1 are identical to or different from one another and correspond to:
\u0394C1-C10 alkyl or
where a=0 and R9 and R10 are identical or different and each correspond to hydrogen or a hydrophilic monovalent radical selected from the group consisting of amino, (poly)hydroxylated, alkoxylated and (poly)etherified hydrocarbon radicals of the (cyclo)alkyl, aralkyl, alkylaryl, (cyclo)alkenyl, aralkenyl, alkenylaryl or aryl type, and mixtures thereof;
the radicals R2 are identical to or different from one another;
the radicals R3 are identical to or different from one another;
the radicals R6 are identical to or different from one another;
the radicals R7 are identical to or different from one another,
R2, R3, R6 and R7 being identical to or different from one another and corresponding to H or a C1-C10 alkyl;
the radicals R4 are identical to or different from one another and correspond to a hydrophilic divalent group selected from the group consisting of aromatic amino groups, hydroxylated groups, aromatic and alkyl amino andor hydroxylated groups, aromatic and (cyclo)alkylenic amino andor hydroxylated groups and (cyclo)alkylenic amino andor hydroxylated groups, said groups optionally containing alkoxy andor (poly)ether radicals,
the divalent group R5 is an alkylene group or a group having the same definition as R4; or
the group R8 corresponds to a hydroxyl, to A4 having the same definition as A1, A2 and A3, to hydrogen or to \u2014NR9R10, where R9 and R10 are identical to or different from one another and are a hydrophilic monovalent radical selected from the group consisting of amino, (poly)hydroxylated, alkoxylated and (poly)etherified hydrocarbon radicals and mixtures thereof, the hydrocarbon radicals being of the (cyclo)alkyl, aralkyl, alkylaryl, (cyclo)alkenyl, aralkenyl, alkenylaryl or aryl type.
3. Process according to claim 2, wherein R9 and R10 each corresponds to a C1-C10 hydroxyalkyl, a C1-C10 alkoxy or a polyol.
4. Process according to claim 3, wherein the polyol is a hydrogenated saccharide.
5. Process according to claim 2, wherein R4 is a group
where R13 is an amino group and R14 is a C1-C4 alkylene.
6. Process according to claim 2, wherein R8 is a C1\u2014C10 hydroxyalkyl, a C1\u2014C10 alkoxy or a polyol.
7. Process according to claim 6, wherein the polyol is a hydrogenated saccharide.
8. Process according to claim 1, wherein the transmembrane pressure is greater than or equal to 0.1 MPa.
9. Process according to claim 8, wherein the transmembrane pressure is between 0.2 and 1.0 MPa.
10. Process according to claim 1, wherein the ions of the metal(s) to be separated are subjected to selective complexation.
11. Process according to claim 1, wherein the at least one ligand has a molecular weight which is greater than a known cut-off threshold of the nanofiltration membrane.
12. Process according to claim 1, wherein the at least one ligand is of formula (I.1):
in which R9, R10, R11 and R12 are identical to or different from one another and each is a hydrophilic monovalent radical.
13. Process according to claim 12 wherein the hydrophilic monovalent radicals are selected from the group consisting of ethanoyl, methoxyethyl and sorbitoyl radicals.
14. Process according to claim 1, wherein several metal species belonging to the lanthanide andor actinide family are separated, said separation being effected by successive complexations of the ions of each of these species to be separated, a selective ligand being chosen for each species in step a), a nanofiltration in step b) and a decomplexationcollection in step c) being carried out after each complexation.
15. Process according to claim 1, wherein the nanofiltration membrane is made of at least one material selected from the group of polymers consisting of polyaramides, sulfonated polysulfones, polybenzimidazolones, grafted or non-grafted polyvinyldidene fluorides, polyamides, cellulose esters, cellulose ethers, perfluorinated ionomers, associations of these polymers, and copolymers obtained from monomers of at least two of these polymers.
16. Process according to claim 1, wherein the nanofiltration membrane has a cut-off threshold of 100-5000 gmol.
17. Process according to claim 16, wherein the cut-off threshold is 200-2000 gmol.
18. Process according to claim 17, wherein the cut-off threshold is 500-1500 gmol.
19. Process according to claim 1, wherein said treating takes place in an aqueous medium at a pH between 1 and 6.
20. Process according to claim 1, wherein the aqueous medium treated is derived from spent nuclear fuel.
21. A complexing agents having one of the formulae:
n being between 1 and 100, and
22. Complexing agent according to claim 21, of formula (I\u2032.2) wherein n is between 1 and 10.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A ceramic discharge vessel for a lamp, comprising:
a hollow body; and
two capillaries attached to said body and having respective electrodes therein, wherein respective portions of said electrodes inside said body are spaced from each other and have longitudinal axes that are not coplanar.
2. The discharge vessel of claim 1, wherein said electrodes have tips inside said body that together define a Z axis, and wherein a plane containing one of the longitudinal axes and said Z axis intersects a plane containing the other of the longitudinal axes and said Z axis at an angle in a range of greater than 0\xb0 to 90\xb0.
3. The discharge vessel of claim 2, wherein the range is at least 3\xb0 to 90\xb0.
4. The discharge vessel of claim 1, wherein said electrodes have tips inside said body that together define a Z axis, and wherein said two capillaries have respective longitudinal axes that are each perpendicular to the Z axis.
5. The discharge vessel of claim 1, wherein said electrodes have tips inside said body that together define a Z axis, and wherein said two capillaries have respective longitudinal axes that each makes a respective acute angle with the Z axis.
6. A ceramic discharge vessel for a lamp, comprising:
a hollow body;
a first hollow capillary attached to said body; and
a second hollow capillary attached to said body and spaced from said first capillary,
wherein a longitudinal axis of said first capillary and a point where said second capillary is attached to said body define a plane, and wherein a longitudinal axis of said second capillary intersects said plane only at said point.
7. The discharge vessel of claim 6, wherein said body has a central axis, and wherein a plane containing one of the longitudinal axes and said central axis intersects a plane containing the other of the longitudinal axes and said central axis at an angle in a range of greater than 0\xb0 to 90\xb0.
8. The discharge vessel of claim 7, wherein the range is at least 3\xb0 to 90\xb0.
9. The discharge vessel of claim 6, wherein said body has a central axis, and wherein said two capillaries have respective longitudinal axes that are each perpendicular to the central axis.
10. The discharge vessel of claim 6, wherein said body has a central axis, and wherein said two capillaries have respective longitudinal axes that each makes a respective acute angle with the central axis.
11. A ceramic discharge vessel for a lamp, comprising:
a hollow body;
a first capillary attached to said body and having a first electrode therein;
a second capillary attached to said body and having a second electrode therein, said first and second electrodes having respective electrode tips inside said body that together define a Z axis,
wherein a longitudinal axis of said first electrode and said Z axis define a first plane that is different from a second plane defined by a longitudinal axis of said second electrode and said Z axis.
12. The discharge vessel of claim 11, wherein said first plane intersects said second plane at an angle in a range of greater than 0\xb0 to 90\xb0.
13. The discharge vessel of claim 12, wherein the range is at least 3\xb0 to 90\xb0.
14. The discharge vessel of claim 11, wherein said first and second capillaries have respective longitudinal axes that are each perpendicular to said Z axis.
15. The discharge vessel of claim 11, wherein said first and second capillaries have respective longitudinal axes that each makes a respective acute angle with said Z axis.