| 摘要 |
A method and apparatus for reconditioning waste solutions of the nuclear industry which contain ammonium nitrate. The waste solution is continuously sprayed from above into a 300 DEG to 600 DEG C. hot zone, from the lower end of which the decomposition products are withdrawn and are separated into condensate and exhaust gas. The NO content is reduced by adding oxygen, especially at the exit of the decomposition zone. By the presence of reducing agents, such as CO(NH2)2 or preferably NH3, in the solution to be sprayed, the NO2 content of the decomposition products and the NH4NO3 residue in the condensate can be practically eliminated and an additional precipitation in the condensate which can be filtered off can be obtained. Optimal contents are 0.25-0.4 Mol NH3 and 0.15-0.25 Mol CO(NH2)2 per Mol NH4NO3. Prior to the thermal decomposition, the waste solution is preferably concentrated, cooled off, and filtered to about 60% or (if a solution containing reducing agents is to be sprayed) about 48% NH4NO3 at about 60 DEG C. in a thin layer evaporator, and is temporarily stored at room temperature. The addition of ammonia to the concentrate offers a precipitation which can be filtered off.
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