PROCEDIMENTO PER L'ELIMINAZIONE DEI COMPOSTI SOLUBILI DI BORO DAGLI EFFLUENTI ACQUOSI

Soluble boron cpds. are removed from aq. effluents by adding with stirring a divalent metal sulphate M'SO4 and a divalent metal hydroxide M2(OH)2, the cpds. being chosen as they react to form insoluble pptes. M'(OH)2 and M2SO4, and the amt. of M2(OH)2 being at least stoichiometric with the amt. of M'SO4. The effluent is allowed to settle, the filtered or centrifuged to remove the ppte. contg. the boron. The sulphate-hydroxide couples are BeSO4-Ba(OH)2, BeSO4-Sr(OH)2, BeSO4-Ca(OH)2, MgSO4-Ba(OH)2, MgSO4-Sr(OH)2, MgSO4-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, CdSO4-Sr(OH)2 and CdSO4-Ca(OH)2. The pH is 7-10, when ZnSO4 is used, and 10-13 in all other cases. The sulphate and the hydroxide may be added in either order, to the continuously stirred water. The temp. is not critical. The quantity of one of the cpds. used may be adjusted if necessary if the water already contains one or more of the ions participating in the reaction. The method leaves a very low final B concn. and can handle waters of high or low B content.