Patent ID: 8900545

Claim:
A process for obtaining magnesium hydroxide from a starting material which is a solid mixture or compound containing magnesium in the carbonate, hydroxide or oxide form, characterized by the steps of: (a) leaching the starting material with an acid; (b) separating precipitated insoluble, inert substances and carbon dioxide from a magnesium solution, all resulting materials from the leaching of step (a); (c) reacting the magnesium solution obtained from the separation step (b) with an alkali; (d) separating the magnesium hydroxide formed as final product from a remaining liquid from step (c); (e) regenerating the acid and the alkali by electrodialysis of the remaining liquid material of step (d); and (f) recycling the regenerated acid to the leaching step (a) and the regenerated alkali to the reaction step (c).