System and process for production of magnesium metal and magnesium hydride from magnesium-containing salts and brines
A system and process are disclosed for production of consolidated magnesium metal products and alloys with selected densities from magnesium-containing salts and feedstocks. The system and process employ a dialkyl magnesium compound that decomposes to produce the Mg metal product. Energy requirements and production costs are lower than for conventional processing.
1. A process, comprising the steps of:
forming a dialkyl magnesium compound by reacting an anhydrous magnesium-containing salt with an alkyl-lithium compound at a selected temperature, wherein the alkyl-lithium compound is obtained by reacting lithium metal and an olefin over a hydrometallation catalyst of the form Cp 2 MX 2 or Cp 2 MX(L), where (M) is a selected metal, (Cp) is cyclopentadiene, X is Cl, Br, and/or I, and the ligand (L) is a pyrrole, an amine, or a phosphinimine, or by reacting lithium metal with a phenylbutylthioether immobilized on a solid support; and
decomposing the dialkyl magnesium compound to form magnesium hydride or magnesium metal.
2. The process of claim 1 , wherein the anhydrous magnesium-containing salt is anhydrous MgCl 2 .
3. The process of claim 1 , wherein the alkyl-lithium compound and the dialkyl magnesium compound include an alkyl group with a carbon number selected between about C 2 to about C 8 .
4. The process of claim 1 , wherein the alkyl-lithium compound and the dialkyl magnesium compound include an alkyl group that is a butyl group.
5. The process of claim 1 , wherein forming the dialkyl magnesium compound includes a transmetallation reaction at a selected temperature.
6. The process of claim 1 , wherein decomposition of the dialkyl magnesium compound includes formation of alkene hydrocarbons with a carbon number between about C 2 to about C 8 .
7. The process of claim 1 , wherein the Mg metal product is a fully consolidated (dense) metal product, or a partially consolidated metal product.
8. The process of claim 1 , wherein the MgH 2 product is produced at a yield selected at or above about 90% by weight.
9. A system, comprising:
a hydrometallation stage that reacts lithium metal and an olefin over a selected hydrometallation catalyst forming an alkyl lithium compound;
a metallation stage that reacts an anhydrous magnesium-containing salt with the alkyl-lithium compound at a selected temperature to form a dialkyl magnesium compound; and
a decomposition stage that decomposes the dialkyl magnesium compound received from the metallation stage at a selected temperature to form magnesium hydride or magnesium metal in a selected form.
10. The system of claim 9 , wherein the metallation stage includes a transmetallation catalyst that forms the dialkyl magnesium compound at a temperature above about 250° C.
11. The system of claim 9 , wherein the decomposition stage decomposes the dialkyl magnesium compound in an inert atmosphere or under vacuum at a temperature above 150° C. and forms the consolidated magnesium metal product at a yield greater than or equal to about 90%.
12. The system of claim 9 , wherein the decomposition stage decomposes the dialkyl magnesium compound at a temperature at or below about 250° C. that forms MgH 2 at a yield at or above about 90% by weight that promotes consolidation of the magnesium metal product formed therein.
13. The system of claim 9 , wherein decomposition of the dialkyl magnesium compound in the decomposition stage includes formation of alkene hydrocarbons with a carbon number between about C 2 to about C 8 .