Patent Number: 048427730
Section: description

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION In the process diagram shown in FIG. 1, the bentonite 1 passes via a solid material metering device 2 into a dispersing pump 5 and the radioactive water 3 is passed into the pump 5 via a control valve 4. The dispersing pump 5 develops high shearing forces and the two materials bentonite 1 and the radioactive water 3 are mixed in the pump. A bentonite-water suspension 6 produced in this manner is pumped via a conduit 7 into a swelling container 8. The suspension 6 remains in the swelling container 8 between 5 and 25 hours to obtain an optimal absorption of the water by the bentonite. To obtain an improved handling of the thixotropic suspension 6, a circulation with a circulating pump 9 is provided via a circulating line 10. The configuration of the swelling container and of the circulating operation can be varied and can be determined in correspondence with the conditions present at a particular facility and to obtain an optimization of the process. As an alternative, a standing cylindrical container equipped with a stirring unit could be used, for example. After the required swelling time, the bentonite suspension 11 is pumped with the aid of a conduit pump 12 functioning as a metering pump to a mixing device 15 via a conduit 13 equipped with appropriate conduit components 14. Cement 16 is added to the swollen bentonite suspension in the mixing device 15 via a metering device 17. All dry-wet mixing systems are suitable as a mixing device which provide an optimal mixing of both components (bentonite-suspension and cement) such as a screw mixer or dispersing pump. The finished mixed product 18 is pumped into a terminal storage container 22 for curing with the aid of a solid-material pump 19 via a conduit 20 having components 21. The terminal storage container is gas-tight after the charging opening has been welded. The measurement positions 23 shown make possible a balancing of the mass currents. FIG. 2 shows a process diagram for providing a continuous process operation. The swelling container 8 utilized in the discontinuous process as well as the components (9, 10, 12, 14) of FIG. 1 are replaced in FIG. 2 by a retention segment 24. Experiments have shown that a hold-up time in the retention segment of greater than 10 minutes changes the characteristics of the swollen bentonite suspension 11 such that no residual water occurs in the end product 18 after hardening. The shorter swelling time requires an extended hardening time of the product. During a six-week experimental phase, reproducible products were produced with both methods which had a water content of up to 90% by weight without residual water occurring after hardening. For products having a water component portion of 85% corresponding to a volume portion of 93.5%, 80 kg of activated bentonite and 95 kg of portland blast-furnace cement were mixed with 1000 liters of water. The cement is known commercially in Germany as HOZ 35L-NW-HS (DIN). A standardized terminal storage container with a net volume of 7 m.sup.3 was filled up to 92% with the product. It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.