Magnesium metal is a critical ingredient for aluminum alloys and it is widely used for desulfurization in steelmaking processes. Most magnesium metal is produced in China via high-energy-consumption processes.
Now, technology company Magrathea (San Francisco, Calif.; www.magratheametals.com) has developed a next-generation electrolyzer for magnesium metal production that makes the process more environmentally friendly and offers a U.S.-based supply of the metal.
The new electrolyzer was recently started in the company’s pilot facility in Oakland, Calif., where it is now producing magnesium metal from anhydrous MgCl2.
The electrolytic route to Mg requires a dehydration step in which water is removed from MgCl2 before an electric current is applied. “What we have done is to carefully engineer a drying process for the MgCl2 that improves efficiency and lowers the costs for making anhydrous MgCl2,” explains Magrathea CEO Alex Grant. To do this, the company uses excess heat from the electrolyzer, where Mg is separated from chlorine, to dry the MgCl2. In addition, the process generates a co-product (MgO), which can trap CO2 in air or seawater to make MgCO3, further reducing emissions.
As Magrathea collects data from the pilot-scale facility, it is planning to build a 1,000-ton/yr demonstration plant starting next year. “We expect that the development will significantly reduce carbon footprint and operating expenses for the process,” Grant says, offering a climate-friendly and cost-competitive alternative to foreign-produced magnesium.