The way non-aqueous dissolution of uranium and uranium-containing materials

 

(57) Abstract:

The invention relates to methods of non-aqueous dissolution of uranium and uranium-containing materials and can be used to extract uranium from spent nuclear fuel, metallurgical wastes of uranium and its alloys and products. The method involves the oxidation of uranium in the solvent. As oxidant use of dissolved gases, such as chlorine, nitrogen oxides, sulfur dioxide. As the solvent used dipolar aprotic solvent or a mixture of chlorine-containing compound. Dipolar aprotic solvent can be trialkylphosphine, dialkylphosphate, trialkylphosphines, amides, organic acids, diallylsulfide, NITRILES, esters. As chlorinated compounds using trichloroethylene at a concentration of 0-90%. The dissolution is carried out at 10-90C. the Invention allows quickly and completely dissolving uranium metal and uranium-containing materials in the absence of water using cheap oxidants in fire conditions. 5 C.p. f-crystals, 1 table.

The present invention relates to methods of dissolution of uranium and can be used to extract uranium from spent nuclear that is ASS="ptx2">There is a method of dissolving materials containing metallic uranium, including the oxidation of uranium metal with a mixture of tributyl phosphate-kerosene containing nitric acid [U.S. Patent No. 3288568, 1966].

The disadvantages of this method associated with an increased destruction of the organic solvent from the use of nitric acid and increased Flammability of the system due to the use of kerosene.

One of the most intimate ways of dissolving uranium metal is a process involving the oxidation of uranium metal with a solution of bromine in ethyl acetate when heated [Larsen R. P. Dissolution of uranium metal and its alloys. Analit. chem. V. 31, No. 4, p.545-549].

The disadvantages of this method is the use of volatile flammable solvent, brainwashes when used temperatures (70-80C). Also the disadvantages include use as an oxidant rather expensive bromine.

The technical result of the invention consists in the rapidity of dissolution of uranium-bearing materials, the lack of allocation of explosive gases, used as oxidant cheap gases - chlorine, nitrogen oxides, sulfur dioxide in fire conditions.

Tehnicheskiiy uranium in the solvent, where the oxidant is used, the gases dissolved in the solvent, and the solvent is a dipolar aprotic solvent or a mixture of a dipolar aprotic solvent and a chlorinated solvent. As the oxidant used chlorine, nitrogen oxides, sulfur dioxide, with the dissolution is conducted at 10-90C. as the dipolar aprotic solvent used trialkylphosphine, dialkylphosphate, trialkylphosphines, amides, organic acids, diallylsulfide, NITRILES, esters. As a chlorinated solvent use tetrachlorethylene, in the concentration range 0-90% vol.

Using trialkylphosphates, dialkylphosphate, trialkylphosphines, amides, organic acids, diallylsulfide, NITRILES, esters dramatically increase the concentration in the liquid phase oxidant is chlorine, nitrogen oxides, sulfur dioxide, which increases the dissolution rate of uranium. Use as an oxidizer such waste products as chlorine, nitrogen oxides, sulfur dioxide allows the use of cheap oxidants to dissolve the uranium. Use as diluent tetrachloroethylene can improve fire safety system, makes Providence uranium metal, equal to 10C, due to the fact that at a lower temperature dissolution of uranium and uranium-containing materials is slow. The upper temperature limit is due to the high intensity of removal of gaseous oxidant from the reaction mixture.

According to the invention the method is as follows.

In a heated reactor equipped with a reflux condenser, was placed a mixture of organic solvent and diluent, to produce saturation of the organic solvent with gaseous oxidant to a certain concentration, then add uranium-containing raw material and the mixture is stirred for a certain period of time.

Example 1.

10.2 g of waste uranium metal in the form of chips were treated for 60 minutes with 100 ml of a 1.2 M solution of chlorine in a mixture of DMF (30 vol.%) - TAE (70% vol.) in a reactor with a stirrer and heated at 40C. the Flakes have dissolved completely.

The results of the other samples are summarized in table.

The invention allows quickly and completely dissolving uranium metal and uranium-containing materials in the absence of water using cheap oxidants in fire conditions.

1. The way non-aqueous dissolution of uranium Elites use gases, dissolved in the solvent, and the solvent is a dipolar aprotic solvent or a mixture of a dipolar aprotic solvent and chlorine-containing diluent.

2. The method according to p. 1, characterized in that as the oxidant used chlorine, nitrogen oxides, sulfur dioxide.

3. The method according to p. 1 and 2, characterized in that the dissolution is carried out at 10 - 90S.

4. The method according to p. 1, characterized in that as the dipolar aprotic solvent used trialkylphosphine, dialkylphosphate, trialkylphosphines, amides, organic acids, diallylsulfide, NITRILES, ethers.

5. The method according to p. 1, characterized in that as a chlorinated solvent use tetrachlorethylene.

6. The method according to p. 1 and 4, characterized in that the concentration of tetrachloroethylene is 0 - 90%.

 

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