Patent ID: 7048843

Claim:
A process for the preparation of metal hydroxides or basic metal carbonates by anodic dissolution of corresponding metals and precipitation of the hydroxides or basic carbonates in an aqueous medium, said process comprising: (a) providing a three-chamber electrolytic cell comprising an anode chamber, a cathode chamber and an intermediate chamber interposed between said anode chamber and said cathode chamber, said intermediate chamber being separated from each of said anode chamber and said cathode chamber by a porous membrane, said anode chamber having an outlet and an anode fabricated from at least one metal that is to be anodically dissoluted, said intermediate chamber having an inlet, and said cathode chamber having an outlet; (b) providing a precipitation reactor that is in fluid communication with said outlet of said anode chamber and said outlet of said cathode chamber, said precipitation reactor being separate from said three-chamber electrolytic cell and not being an electrolytic cell; (c) performing the anodic dissolution of the metals in said anode chamber of said three-chamber electrolytic cell; (d) feeding an aqueous auxiliary salt solution continuously into said intermediate chamber by means of said inlet of said intermediate chamber, wherein said aqueous salt solution consists of water and an auxiliary salt selected from the group consisting of alkali metal chlorides, alkaline earth metal chlorides, alkali metal nitrates, alkaline earth metal nitrates, alkali metal sulfates, alkaline earth metal sulfates, alkali metal acetates, alkaline earth metal acetates, alkali metal formates, alkaline earth metal formates and combinations thereof; (e) removing an at least non-alkaline metal salt solution continuously from the outlet of said anode chamber, (f) removing an alkaline auxiliary salt solution continuously from the outlet of said cathode chamber, and (g) combining, the at least non-alkaline metal salt solution removed from said outlet of said anode chamber, and the alkaline auxiliary salt solution removed from said cathode chamber, in said precipitation reactor, thereby forming precipitated metal hydroxides or basic metal carbonates and a precipitation solution.