COMPOSITE MATERIAL FOR IMMOBILISATION OF TOXIC RADIOACTIVE CHEMICAL WASTES (VERSIONS) Russian patent published in 2010 - IPC G21F9/16 

FIELD: nuclear physics.

SUBSTANCE: invention relates to nuclear technology and processing radioactive wastes of low and medium level of activity. The composite material for immobilisation of radioactive and chemical toxic wastes based on magnesia cement contains a hardener solution which consists of tempering liquid, magnesia cement and filler, where the tempering liquid is an aqueous magnesium sulphate solution with density of 1.1-1.3 g/cm³, wherein the magnesia cement in the hardener solution is in form of caustic magnesia powder. The composite material additionally contains a catalytic carbon-containing additive with the following ratio of components, wt %: caustic magnesia powder - 30-50; filler - 30-50; catalytic carbon-containing additive - 0.01-0.5; aqueous magnesium sulphate solution - the rest. The magnesium sulphate solution used is an espmite solution with density 1.1-1.3 g/cm³. To achieve the objective, the composite material for immobilising toxic radioactive and chemical wastes in accordance with the second version is similar to the first version except that, the tempering liquid in the hardener solution is an aqueous magnesium chloride solution with density of 1.2-1.35 g/cm³, with the following ratio of components, wt %: caustic magnesia powder - 30-50; filler - 30-50; catalytic carbon-containing additive - 0.01-0.5; aqueous magnesium chloride solution - the rest. In both versions the catalytic carbon-containing additive used is pyrocarbon, white soot or schungite rock. Also the filler in the composite material is metallic slag with particle size of up to 0.074 mm or ash from burning organic and/or inorganic substances. The composite material also contains a vitrifying additive in form of bentonite clay in amount of up to 0.5 wt %.

EFFECT: high and uniform degree of filling the compound with wastes with formation of a surface layer on the compound which is low-permeable by radioactive nuclides, high mechanical strength and moisture resistance of the compound for long periods of time.

15 cl, 6 ex