Method for solidifying liquid wastes containing radioactive or toxic material

When aqueous solutions containing radioactive or toxic waste are solidified disturbing heat production or effervescence often occurs. This can be avoided if to such solutions, which may have a relatively high acid or alkali content, a mixture of calcium sulfate and a porous solid substance (e.g. broken stone from ceramic bricks) is added. Mixing ratio solid/liquid is given as 0.7 to 1.3 kg for 500 ml, calcium sulfate to the addition is 1 in about 0.5 to 3. The mixing should take place in stirrers. For calcium sulfate and the addition material exact criteria are given. (orig./PW)