Means for the conditioning of radioactive or toxic waste in cement and its production process
AssigneeCommissariat a l'Energie Atomique
InventorPascal Bouniol
Life of this patent
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Abstract
A process for conditioning radioactive or toxic waste which can contain boron in a cement-based matrix comprises mixing the waste in a drum in the presence of water with non-aluminous cement, aluminous cement and optionally a siliceous compound and/or a boron-containing compound, in order to form a cement matrix containing stable phases of the straetlingite, calcium monoboroaluminate and borated ettringite type and, if desired, placing around the drum a mortar layer, which can be prepared from cement, deflocculated fumed silica, siliceous sand, smectic clay and water.
Claims16
A process for the conditioning of radioactive or toxic waste which can contain borate ions in a cement-based solid matrix with a view to the storage thereof, which comprises the following successive steps:
- (a) mixing the waste, in the presence of water, with aluminous cement, non-aluminous cement and optionally a compound containing either or both silicon and boron in proportions such that a mixture is formed, which gives rise to the crystallization of at least one stable mineral phase selected from the group consisting of the type straetlingite, calcium monoboraluminate and borated ettringite phases, apart from the standard hydrates of the non-aluminous cement, and
- (b) allowing the mixture to harden in order to form the solid matrix containing at least one of these phases.
Dependencies are inferred from the claim text.