Selective metal extn. from soln. - by controlled pH variation in cathodic zone of diaphragm cell

Metals are selectively extracted from leach solns. by dividing a d.c. field region into an anodic zone and a cathodic zone through which solns. to be treated are passed simultaneously. The pH of the soln. in the cathodic zone is maintained at a value in the range 1-14 by applying external electric and magnetic fields, the feed rate of the soln. and the rate of pH variation being selected for selective pptn. of (hydr)oxides of different metals at different respective pH values within the pH range. The leach soln. may be passed simultaneously through the cathodic and anodic zones; alternatively, an aq. chloride soln. (e.g. a sylvinite soln.) or an aq. sulphate soln. (e.g. a sodium sulphate soln.) may be passed through the anodic zone instead of the leach soln. The process is useful for selective extraction of non-ferrous metals from natural or synthetic leach solns., chemical etching solns., and waste water and other waters. Addn. of alkali for pptn. of the metals and the provision of activated carbon in the inter electrode space are not required. Metals can be recovered from strong or weak solns. with max. yield and min. energy expenditure. LA PRESENTE INVENTION SE RAPPORTE A UN PROCEDE D'EXTRACTION DES SOLUTIONS DE LIXIVIATION ET A UN DISPOSITIF POUR LA MISE EN OEUVRE DE CE PROCEDE.L'INVENTION EST CARACTERISEE PAR LE FAIT QU'UN ESPACE 5 SOUMIS A L'ACTION D'UN CHAMP ELECTRIQUE CONTINU EST DIVISE EN UNE ZONE ANODIQUE 6 ET UNE ZONE CATHODIQUE 7 PAR LESQUELLES ON FAIT PASSER SIMULTANEMENT LES SOLUTIONS A TRAITER, EN MAINTENANT DANS LA ZONE CATHODIQUE UN PH DE LA SOLUTION DANS UN INTERVALLE DE 1 A 14 GRACE A L'APPLICATION D'UN CHAMP ELECTRIQUE ET D'UN CHAMP MAGNETIQUE EXTERIEURS.L'INVENTION PEUT TROUVER APPLICATION DANS L'HYDROMETALLURGIE DE METAUX NON-FERREUX.