METHOD OF RADIOACTIVE SALT WASTE DEACTIVATION IN PROCESS OF RARE-EARTH TITANIUM NIOBATES CHLORINATION Russian patent published in 2008 - IPC G21F9/00 

FIELD: chemistry.

SUBSTANCE: invention concerns metallurgy, particularly metallurgy of rare, trace and radioactive metals, and can be specifically applied in processing, neutralisation and deactivation of radioactive salt waste obtained during chlorination of rare-earth titanium niobates, also known as loparite concentrates containing rare-earth elements, Nb, Ta, Ti, admixtures of Fe, Al, up to 0.6% of thorium and up to 0.1% of uranium, daughter decay products and others. The method includes water dissolution of exhausted salt reflux filter melt by hydro-erosion, salt solution neutralisation with an alkali reagent, slurry filtration separation of mother solution from radioactive sediments. According to the invention, source radioactive solutions are diluted in 1.5-2.5 times with workfloor washing water before processing in alkali reagent, processing of the diluted solution by sodium hydroxide till pH is 11-13. Further aluminium chloride solution is added to the slurry at the amount of 8.5-11.5 g (kg) Al³⁺ per 1 dm³ (m³) of the source solution and stirred, the pulp is continuously stirred and tempered at pH of 10-11 for 1-2 hours, an filtered, radioactive sediment of total metal oxyhydrates is separated from the mother solution, which is drained down to workfloor sewers.

EFFECT: streamlining and efficiency boost of deactivation technology.

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