Turning magnesium phosphate into magnesium and phosphoric acid?

Add sulfuric acid. This will produce magnesium sulfate and phosphoric acid. Melting the magnesium sulfate and electrolyzing is not feasible because MgSO4 decomposes at around 1100 degrees Celsius to MgO and SO3, and the MgO will melt only at 2800 degrees Celsius. Instead, add aqueous sodium hydroxide to the MgSO4, which will precipitate Mg(OH)2, magnesium hydroxide. Remove this precipitate and add hydrochloric acid to it to produce aqueous magnesium chloride. After boiling the water off the MgCl2 can be melted (mp = 714 �C) and electrolyzed to recover pure Mg metal.