MEANS FOR THE CONDITIONING OF RADIOACTIVE OR TOXIC WASTE IN CEMENT AND ITS PRODUCTION PROCESS

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.