CERAMIC SPONGE FOR CONCENTRATION AND HARDENING OF LIQUID EXTRAHAZARDOUS WASTE AND METHOD FOR ITS PRODUCTION Russian patent published in 2001 - IPC

FIELD: processing of liquid extrahazardous waste containing heavy metals and/or radionuclides, in particular, hardening of waste by inclusion of them in artificial ceramic compounds, applicable at radiochemical plants of nuclear power and nuclear-armory complexes, as well as in chemical and metallurgical industries. SUBSTANCE: for concentration and hardening of liquid extrahazardous waste use is made of a ceramic sponge based on hollow aluminosilicate microspheres, more than 20 μm in diameter, wall thickness exceeding 0.3 g/cu.cm, characterized by thermal stability and mechanical strength exceeding 2 MPa, as well as possessing an open porosity with an accessible unconfined space up to 70%. For its production hollow aluminosilicate microspheres are extracted from the flash obtained after burning of coals, mixed with a wetting agent and silicate binder at a ratio of weight of the components within 1:0.012-0.29:18 with formation of moulding mass, gas inclusions are removed from it with simultaneous moulding of blocks of preset dimensions and sintered at a temperature exceeding 800 C, but lower than the softening temperature, and at atmospheric pressure. EFFECT: enhanced mechanical strength while in transit, at rehandling and in storage, as well as acid resistance and thermal stability. 4 cl