Production of magnesium metal

Abstract

A process of producing magnesium metal includes providing magnesium carbonate, and reacting the magnesium carbonate to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The carbon dioxide is used as a reactant in a second process. In another embodiment of the process, a magnesium silicate is reacted with a caustic material to produce magnesium hydroxide. The magnesium hydroxide is reacted with a source of carbon dioxide to produce magnesium carbonate. The magnesium carbonate is reacted to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The invention also relates to the magnesium metal produced by the processes described herein.

1 . A system for producing magnesium metal comprising:
 a supply of a magnesium silicate entering the system;   reaction apparatus which converts the magnesium silicate to magnesium metal, with substantially no net production of carbon dioxide or chlorine;   the magnesium metal exiting the system as a product; and   the reaction apparatus in a later step of the process produces carbon dioxide that is recycled back to an earlier step of the process so that the overall process has substantially no net production of carbon dioxide.   
     
     
         2 . The system according to  claim 1  wherein the magnesium silicate comprises serpentine and/or olivine. 
     
     
         3 . A system for producing at least one of magnesium carbonate and magnesium metal comprising:
 a first subsystem comprising: (a) a supply of a magnesium silicate entering the first subsystem; (b) reaction apparatus that converts the magnesium silicate to magnesium hydroxide and an alkali-metal silicate with the use of a caustic material; (c) reaction apparatus that converts the magnesium hydroxide to magnesium carbonate with the use of carbon dioxide; and (d) apparatus for exiting the magnesium carbonate from the first subsystem in order to sequester the carbon dioxide in the magnesium carbonate; and   a second subsystem comprising: (a) apparatus for conveying the magnesium carbonate from the first subsystem to the second subsystem; (b) apparatus for reacting the magnesium carbonate to produce a magnesium-containing compound and carbon dioxide; (c) apparatus for recycling the carbon dioxide from the second subsystem to the first subsystem; and (d) apparatus for reacting the magnesium-containing compound to produce magnesium metal.   
     
     
         4 . The system according to  claim 3  wherein the second subsystem is turned on to produce the magnesium metal, and turned off to produce the magnesium carbonate. 
     
     
         5 . The system according to  claim 4  wherein, when the second subsystem is turned on, the system results in substantially no net production of carbon dioxide. 
     
     
         6 . The system according to  claim 3  wherein the magnesium silicate comprises serpentine and/or olivine.