Process for producing sodium sulphate from phosphogypsum
OwnerKhaoula Khaless, Driss Dhibainventors
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Abstract
The present invention relates to a process for producing sodium sulphate from phosphogypsum, comprising: a step (101) of lixiviation of phosphogypsum by means of a basic solution so as to obtain a sodium sulphate solution (S) containing metal impurities, said basic solution comprising a chelating agent suitable for forming complexes with at least one part of said metal impurities, at least one first step (103, 104) of filtration of the sodium sulphate solution by a nanofiltration membrane (NF1, NF2), so as to form a concentrate (C1, C2) containing said complexes and a permeate (P1, P2), a step (105) of evaporation of the permeate (P1, P2) so as to form anhydrous sodium sulphate.
Claims13
A process for producing sodium sulphate from phosphogypsum, comprising:
- a step of lixiviation of phosphogypsum by means of a basic solution comprising a chelating agent so as to obtain a sodium sulphate solution containing metal impurities, wherein at least one part of said metal impurities form complexes with the chelating agent,
- at least one first step of filtration of the sodium sulphate solution by a nanofiltration membrane, so as to form a concentrate containing said complexes and a permeate,
- a step of evaporation of the permeate so as to form anhydrous sodium sulphate.
Dependencies are inferred from the claim text.