Patent ID: 8846999

Claim:
A method for treating a nitric aqueous liquid effluent containing nitrates of metals or metalloids, comprising the steps of: adding a dilution adjuvant to the effluent; and a step for calcination of the effluent in order to convert the nitrates of metals or metalloids into oxides of said metals or metalloids, at least one compound selected from the nitrates of metals or metalloids and the other compounds of the effluent leading upon calcination to a tacky oxide, wherein the dilution adjuvant comprises at least one nitrate of metal or metalloid leading upon calcination to a non-tacky oxide, the dilution adjuvant being added to the effluent prior to the calcination step in order to give a mixture of effluent and dilution adjuvant, in which the mixture meets the two following inequations (1) (2): mass ⁢ ⁢ of ⁢ ⁢ sodium ⁢ ⁢ nitrate ⁢ ⁢ of ⁢ ⁢ the ⁢ ⁢ mixture expressed ⁢ ⁢ in ⁢ ⁢ terms ⁢ ⁢ of ⁢ ⁢ oxide ⁢ ⁢ Na 2 ⁢ O mass ⁢ ⁢ of ⁢ ⁢ all ⁢ ⁢ the ⁢ ⁢ compounds ⁢ ⁢ of ⁢ ⁢ the mixture ⁢ ⁢ expressed ⁢ ⁢ in ⁢ ⁢ terms ⁢ ⁢ of ⁢ ⁢ oxides ≤ 0.3 ( 1 ) mass ⁢ ⁢ of ⁢ ⁢ all ⁢ ⁢ the ⁢ ⁢ compounds ⁢ ⁢ of ⁢ ⁢ the ⁢ ⁢ mixture leading ⁢ ⁢ upon ⁢ ⁢ their ⁢ ⁢ calcination ⁢ ⁢ to ⁢ ⁢ tacky ⁢ ⁢ oxides , expressed ⁢ ⁢ in ⁢ ⁢ terms ⁢ ⁢ of ⁢ ⁢ oxides mass ⁢ ⁢ of ⁢ ⁢ all ⁢ ⁢ the ⁢ ⁢ compounds ⁢ ⁢ of ⁢ ⁢ the ⁢ ⁢ mixture expressed ⁢ ⁢ in ⁢ ⁢ terms ⁢ ⁢ of ⁢ ⁢ oxides ≤ 0.35 . ( 2 )