Encapsulation composition for storage or confinement of waste which is toxic to health and/or the environment

Abstract

The invention relates to an encapsulation composition for the storage or the confinement of waste which is toxic to health and/or the environment, comprising a resin composition containing at least one epoxy resin, and a hardening composition containing at least one polyamidoamine and at least one aromatic polyamine, said encapsulation composition having an aromaticity rate which is equal to, or higher than, 35%. The invention also relates to the use of said composition for encapsulating said waste.

Claims

1. An encapsulation composition for the storage or confinement of toxic waste, comprising: a resin composition containing at least one epoxy resin, and a hardening composition containing at least one polyamidoamine and at least one aromatic polyamine, said encapsulation composition having a degree of aromaticity greater than or equal to 35%, said degree of aromaticity being defined as follows and expressed as a percentage: $\frac{\begin{array}{c}\mathrm{sum}\mathrm{of}\mathrm{the}\mathrm{molecular}\mathrm{weights}\mathrm{of}\mathrm{the}\mathrm{aromatic}\mathrm{rings}\mathrm{present}\mathrm{in}\\ \mathrm{the}\mathrm{encapsulation}\mathrm{composition}\mathrm{and}\mathrm{included}\mathrm{in}\mathrm{the}\mathrm{polymer}\mathrm{chain}\end{array}}{\begin{array}{c}\mathrm{sum}\mathrm{of}\mathrm{the}\mathrm{molecular}\mathrm{weights}\mathrm{of}\mathrm{all}\mathrm{of}\\ \mathrm{the}\mathrm{components}\mathrm{of}\mathrm{the}\mathrm{encapsulation}\mathrm{composition}.\end{array}}$

2. The composition according to claim 1, wherein the composition comprises from 50 to 80% by weight of the resin composition based on epoxy resin and from 20 to 50% by weight of the hardening composition.

3. The composition according to claim 1, wherein said polyamidoamine has an amine index, corresponding to an equivalent weight per active hydrogen, of the order of 90 to 110 g/H.

4. An encapsulation composition for the storage or confinement of toxic waste, comprising: a resin composition containing at least one epoxy resin, and a hardening composition containing at least one polyamidoamine and at least one aromatic polyamine, wherein said polyamidoamine is a product of the reaction between one or more aliphatic polyethylene polyamine(s) and one or more mono- or polyunsaturated C.sub.12-C.sub.18 fatty acid(s), said encapsulation composition having a degree of aromaticity greater than or equal to 35%, said degree of aromaticity being defined as follows and expressed as a percentage; sum of the molecular weights of the aromatic rings present in the encapsulation composition and included in the polymer chain sum of the molecular weights of all of the components of the encapsulation composition.

5. The composition according to claim 4, wherein the aliphatic polyethylene polyamine is an polyethylenetetramine or an polyethylenepentamine.

6. The composition according to claim 4, wherein the aliphatic polyethylene polyamine is diethylenetriamine, triethylenetetramine, tetraethylenetetramine, tetraethylenepentamine or bis(3-aminopropyl)ethylenediamine.

7. The composition according to claim 1, wherein said aromatic polyamine has a degree of aromaticity from 35% to 70%, said degree of aromaticity being defined as follows and expressed as a percentage: $\frac{\begin{array}{c}\mathrm{sum}\mathrm{of}\mathrm{the}\mathrm{molecular}\mathrm{weights}\mathrm{of}\\ \mathrm{the}\mathrm{aromatic}\mathrm{rings}\mathrm{present}\mathrm{in}\mathrm{the}\mathrm{molecule}\end{array}}{\mathrm{molecular}\mathrm{weight}\mathrm{of}\mathrm{the}\mathrm{molecule}.}$

8. The composition according to claim 1, wherein said aromatic polyamine has a melting point less than or equal to 130° C.

9. The composition according to claim 1, wherein said aromatic polyamine has an equivalent weight per active hydrogen of the order of 80 to 100 g/H.

10. The composition according to claim 1, wherein the aromatic polyamine is a primary diamine.

11. The composition according to claim 1, wherein said aromatic polyamine is diethylmethylbenzenediamine, 4,4′-methylene-bis[2,6-diethylaniline], 4,4′-methylene-bis(3-chloro-2,6-diethylaniline), 4,4′-methylene-bis(2,6-xylidine), 4-methyl-o-phenylenediamine, 4-aminobenzylamine and diethyltoluenediamine (DETDA), used alone or in a mixture thereof.

12. The composition according to claim 1, wherein the polyamidoamine is the product of the reaction between tetraethylenepentamine and the fatty acids of vegetable origin contained in the distillation residues of wood (TOFA) and the aromatic polyamine is diethyltoluenediamine (DETDA).

13. The composition according to claim 1, wherein the resin composition comprises an epoxy resin of which the equivalent weight per epoxy is between 190 and 210 g/mol and in that the number of epoxy functions per molecule (monomer) of said epoxy resin is from 2 to 5.

14. The composition according to claim 12, wherein said epoxy resin is a resin resulting from the reaction between bisphenol A and/or bisphenol F and epichlorohydrin.

15. The composition according to claim 12, wherein the epoxy resin used is a mixture of resin resulting from the reaction between bisphenol A and/or bisphenol F and epichlorohydrin.

16. The composition according to claim 13, wherein the resin composition comprises, relative to the total weight of the resin composition: 70 to 90% by weight of at least one epoxy resin, 5 to 15% by weight of a reactive diluent, 5 to 15% by weight of a plasticizing diluent, 0 to 3% by weight of a thixotropic agent, and 0 to 2% of at least one surfactant, or sequestering agent, or water-repellent agent, the sum of the components of the resin composition not exceeding 100%.

17. A method for preparing an encapsulated waste block comprising: (i) preparing an encapsulation composition by mixing a resin composition and a hardening composition as defined in claim 1, and (ii) incorporating the waste to be encapsulated in said encapsulation composition, and (iii) encapsulating and cross-linking until a cured encapsulated waste block is obtained.

18. The method according to claim 17, wherein mixing the resin composition and hardening composition is carried out at a temperature of 15 to 30° C.

19. The method according to claim 17, wherein at least one of the following conditions is fulfilled: the waste to be encapsulated is in solid form or in semi-liquid form; the waste to be encapsulated is a radioactive or non-radioactive waste; said waste is anionic or cationic ion-exchange resins and mixtures thereof, contaminated magnesium rods, irradiated metallic components, radioactive ash, from heavy metals or materials containing them, metallic components in divided form originating from the dismantling of industrial workshops, or products generating or releasing harmful substances; and/or said encapsulated waste block comprises from 30 to 60% by weight of encapsulation composition and from 70 to 40% by weight of waste.

20. The composition according to claim 1, wherein the composition has a degree of aromaticity from 35% to 45%.

21. The composition according to claim 7, wherein said aromatic polyamine has a degree of aromaticity from 38% to 65%.

22. The composition according to claim 8, wherein said aromatic polyamine has a melting point from 35° C. to 130° C.

23. The composition according to claim 15, wherein the epoxy resin used is a mixture of resin resulting from the reaction between bisphenol A and epichlorohydrin, which is the resin diglycidyl ether of bisphenol A (DGEBA).

24. The composition according to claim 16, wherein the resin composition comprises, relative to the total weight of the resin composition: 85 to 90% by weight of at least one epoxy resin, 8 to 12% by weight of a reactive diluent, 5 to 10% by weight of a plasticizing diluent, 1 to 2% by weight of a thixotropic agent, and 0 to 2% of at least one surfactant, or sequestering agent, or water-repellent agent, the sum of the components of the resin composition not exceeding 100%.

Description

EXAMPLE 1

Preparation of an Encapsulation Composition

(1) The following encapsulation composition was prepared:

(2) 1) Epoxy resin composition

(3) TABLE-US-00001 Content (% by Component weight) Diglycidyl ether of bisphenol A (DGEBA) epoxy resin, 89 functionality f = 2 ethylhexyldiglycidyl ether (reactive diluent), 6.9 epoxy functionality = 2 Benzyl alcohol (plasticizing diluent) 2.9 Hydrophobic pyrogenic silica (thixotropic agent) 1.2 2) Hardening composition with 31.75 parts of hardener composition per 100 parts of epoxy resin composition (i.e. 24.1% of hardener)

(4) TABLE-US-00002 Content (% by Component weight) Product of the reaction between tetraethylenepentamine 55 and fatty acids of vegetable origin contained in wood distillation residues (TOFA) (Ancamide 506 from AIR PRODUCTS) DETDA (lonzacure DETDA 80 from LONZA) 45 Degree of aromaticity = 41%

(5) Mixing was carried out by kneading the resin composition with the hardening composition for 5 to 10 min at ambient temperature between 15 and 30° C., these compositions having been assayed beforehand and brought to a temperature of 20 to 25° C. The degree of aromaticity of the encapsulation composition is 36.4%. This high degree of aromaticity allows the encapsulation composition obtained to meet the required technical specifications with respect to resistance to ionizing radiation and mechanical strength.

(6) The waste to be encapsulated is incorporated immediately after mixing.

Example 2

Encapsulation of an Ion-Exchange Resin

(7) 58 kg of epoxy resin composition and 28 kg of hardening composition from Example 1 are mixed together in a 200-litre metal drum.

(8) The mixture is kneaded using a mixing rotor with a diameter of 520 mm, with a single stage and 4 blades with a width of 200 mm oriented at 45°, with a stirrer at a speed of 60 rpm for 1 to 2 min.

(9) 119 kg of ionically equilibrated polystyrene or acrylic ion-exchange resins (Amberlite MB20 from ROHM&HAAS) are then added to the mixture immediately at a flow rate of 500 kg/h, with stirring, and then the whole is mixed for 7 min at 60 rev/min, and then for 7 min at 140 rpm.

(10) After stopping for 5 min for degassing, the mixture is homogenized for 5 min at 140 rpm.

(11) A 205 kg block of encapsulated ion-exchange resin is obtained.

(12) In terms of kinetics and exotherm, the values measured during polymerization also meet the specifications of the Agence nationale de gestion des déchets radioactifs (ANDRA) [French national radioactive waste management agency] and in particular comply with a maximum temperature reached below 90° C., which meets the technical specifications required in terms of kinetics.

(13) The results obtained in the test performed according to Examples 1 and 2 show that the performance in terms of compressive strength meets the ANDRA requirements, namely a value of breaking stress above 8 MPa, which meets the required technical specifications in terms of mechanical strength.