Extracting Magnesium from Seawater

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Project Term:
01/01/2014 - 06/30/2016

Critical Need:

Primary production of lightweight metals such as magnesium is an energy-intensive and expensive process that results in significant carbon dioxide (CO2) and other emissions. Lowering the energy consumption, cost, and emissions associated with processing magnesium and its alloys would make it competitive with incumbent structural metals such as steel. Enabling its widespread use in vehicles in particular—without compromising performance or safety—would substantially reduce fuel consumption and CO2 emissions from transportation.

Project Innovation + Advantages:

Pacific Northwest National Laboratory (PNNL) is developing a radically new process to produce magnesium from seawater. Today’s methods are energy intensive and expensive because the magnesium concentration in seawater is so low that significant energy is needed to evaporate off water and precipitate magnesium chloride salt. Further, conventional technologies involve heating the salt to 900°C and then using electric current to break the chemical bond between magnesium and chlorine to produce the metal. PNNL’s new process replaces brine spray drying with a low-temperature, low-energy dehydration process. That step is combined with a new catalyst-assisted process to generate an organometallic reactant directly from magnesium chloride. The organometallic is decomposed to magnesium metal via a proprietary process at temperatures less than 300°C, thus eliminating electrolysis of magnesium chloride salt. The overall process could be significantly less expensive and more efficient than any conventional magnesium extraction method available today and uses seawater as an abundant, free resource.

Potential Impact:

If successful, PNNL would enable a low-cost, low-energy metal-organic process for producing magnesium from seawater without the energy intensive steps associated with conventional processes.


Light-weighting vehicles to improve fuel efficiency could reduce U.S. dependence on foreign fossil fuel resources used in the transportation industry.


Efficiencies in magnesium extraction technologies could offer a 50% reduction in energy consumption and result in substantially fewer CO2 emissions over conventional methods.


Seawater represents a virtually unlimited source of magnesium, which could supply worldwide demand for centuries given an economic and environmentally sound method for its extraction.


ARPA-E Program Director:
Dr. Eric Rohlfing
Project Contact:
Dr. Peter McGrail
Press and General Inquiries Email:
Project Contact Email:


US Magnesium LLC
Global Seawater Extraction Technologies LLC

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