Process and apparatus for electrolytic extraction of magnesium hydroxide from seawater, brines or concentrated solutions uses a two-zone cell at high pH with membrane separation

摘要

Extraction of magnesium hydroxide involves (A) introducing a salt solution or brine into both the cathode (1) and anode (2) zones of a 2-chamber electrolytic cell, the zones being separated by a membrane (3); (B) applying a direct current between cathode (4) and anode (5) of a strength giving a high pH in the salt electrolyte in the cathode zone (1); and (C) loosening the accreted material (9) and removing it from cathode zone (1). An independent claim is also included for an apparatus for the extraction comprising (1) a membrane (3)-separated electrolytic cell with one or more anodes (5) and cathodes (4) near the membrane (3); (2) an inlet (6) for introducing the solution into cathode zone (1) and an outlet (7) for removing used process electrolyte and the Mg(OH)2; (3) an opening (8) in the anode zone (2) introducing and removing the solution; (4) a device removing the Mg(OH)2 (9) from cathode (4); and (5) a conveyor (11) transporting the Mg(OH)2 from the cathode zone (1).