Magnesium chloride production method from seawater

摘要

A method for producing a solution enriched in magnesium chloride (MgC12) from seawater comprises passing seawater 3 through a desalination process 4 to produce a magnesium-enriched brine 6 which is then fed to a cation resin exchanger 7 which adsorbs the magnesium ions from the seawater and then extracting the magnesium chloride into a regenerant solution 8. The method may further comprise the use of a pre-treatment stage 2 which may comprise a screening or filtering stage designed to prevent fouling of the desalination process (eg by sand). The desalination process may be conducted by the use of Multiple Stage Flash distillation (MSF), Multiple Effect Distillation (MED), Thermo-Vapour Compression Multiple Effect Distillation (TVC-MED), Mechanical Vapour Compression Multiple effect Distillation or a reverse osmosis membrane process. The regenerant solution may be an aqueous solution of hydrochloric acid or sodium chloride. Magnesium Chloride may be released from the regenerant solution and/or further concentrated by evaporation, which may be of the thermal or solar type. In use, the concentrated magnesium chloride produced by this process may be used to produce manganese steel or magnesia (MgO).