METHOD FOR TREATING WASTE MATERIAL

Abstract

The present invention relates to a method for treating waste material comprising organic components and low and/or medium level radioactive agents. The method comprises encapsulating the waste material into a matrix, gasifying the waste material at a temperature between 600 and 950° C. to form a gaseous fraction and a solid fraction comprising low and/or medium level radioactive agents and combustion residues of the organic components and encapsulating the solid fraction by a geopolymer matrix comprising metakaolin.

Claims

1. A method for treating waste material comprising organic components and low and/or medium level radioactive agents, the method comprises encapsulating the waste material into a matrix, wherein the method comprises gasifying the waste material at a temperature between 600 and 950° C. to form a gaseous fraction and a solid fraction comprising low and/or medium level radioactive agents and combustion residues of the organic components and encapsulating the solid fraction by a geopolymer matrix comprising metakaolin.

2. The method according to claim 1, wherein the method comprises mixing the solid fraction with metakaolin.

3. The method according to claim 2, wherein the method comprises adding aqueous solution of a silicate or a mixture of silicates and a hydroxide or a mixture of hydroxides to the mixture of the solid fraction and metakaolin.

4. The method according to claim 3, wherein the method comprises adding a sodium silicate or a potassium silicate or both.

5. The method according to claim 3, wherein the method comprises adding sodium hydroxide or potassium hydroxide or both.

6. The method according to claim 3, wherein the method comprises agitating the mixture until a homogenous paste is achieved.

7. The method according to claim 6, whereinwherein the method comprises heating the homogenous paste in humid or autogeneous conditions in order to initiate a polysialate polymerization process.

8. The method according to claim 6, wherein the method comprises settling the homogenous paste at room temperature.

9. The method according to claim 7, wherein the method comprises heating in order to remove water.

Description

DETAILED DESCRIPTION OF THE INVENTION

Example

[0029] Radioactive ion exchange resins are treated with a gasification technique in a temperature of 850° C., i.e. they are treated according to the first method step of the invention. A solid fraction having a reduced volume is obtained from the first method step. The solid fraction resembles at this stage fine ash.

[0030] The gasified solid fraction is mixed with metakaolin (e.g. Metamax, BASF). Aqueous solution of sodium silicate (NaSiO, e.g. Zeopol 33, Huber Engineered Materials) and potassium hydroxide (KOH) is added to the mixture. The mixture is agitated until a homogenous paste is achieved. Mixing can be performed with known mixing devices usually used in connection with encapsulation processes.

[0031] After the solid blank has adequate mechanical properties, it may heated. Thus a finished product to be stored in the bed rock has been formed. The finished product has a loading factor from 75% to above 100%.

[0032] It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.