PROCESS FOR REMOVING SOLUBLE BORON COMPOUNDS FROM AQUEOUS EFFLUENTS

A process for removing boron compounds from aqueous effluents comprises contacting the effluent, under stirring, with a divalent metal sulphate MeISO4 and a divalent metal hydroxide MeII(OH)2, the sulphate-hydroxide couple being selected from BeSO4-Ba(OH)2, BeSO4-Sr(OH)2, BeSO4-Ca(OH)2, MgSO4-Ba(OH)2, MgSO4-Sr(OH)2, MBgSO4-Ca(OH)2, CaSO4-Ba(OH)2, CaSO4-Sr(OH)2, SrSO4-Ba(OH)2, ZnSO4-Ba(OH)2, ZnSO4-Sr(OH)2, ZnSO4-Ca(OH)2, CdSO4-Ba(OH)2, CdSO4Sr(OH)2 and CdSO4-Ca(OH)2. Sulphate MeISO4 and hydroxide MeII(OH)2, by reaction with each other, cause sulphate MEIISO4 and hydroxide MeI(OH)2 to precipitate. The amount of MEII(OH)2 is at least stoichiometric with respect to the amount of MeISO4 and the precipitation pH is within the range of 7 to 10 when MeISO4 is ZnSO4 and 10 to 13 in the other cases. At the end of the precipitation the effluent is decanted and filtered or centrifuged, thus separating the boron-containing precipitate from the purified effluent.