There are two major ways of producing magnesium [1]:<p>1) Electrolytic production from anhydrous magnesium chloride, similar to the electrolytic production of aluminum.<p>2) The Pidgeon process, which currently dominates Chinese (and world) magnesium production. It distills magnesium vapor under vacuum from a heated mixture of ferrosilicon and magnesium-calcium oxide (calcined dolomite).<p>The Pidgeon process has a high global warming potential because of the coal used to produce the ferrosilicon input and to heat the retorts. The electrolytic process has a lower global warming potential, especially if using low-carbon electricity, but historically sulfur hexafluoride has been used as a protective cover gas for the metal during electrolytic production. This gas has a staggering global warming potential 23,900 times that of CO2 [2] so incidental leakage of even small quantities can have a high climate impact.<p>The "without mining" part is not novel. Dow Chemical produced electrolytic magnesium from seawater without mining at Freeport, Texas from 1941-1998, until lower cost foreign magnesium made it uneconomical:<p><a href="https://www.chemicalonline.com/doc/dow-to-exit-magnesium-business-0001" rel="nofollow">https://www.chemicalonline.com/doc/dow-to-exit-magnesium-bus...</a><p>Reading the company's rather sparse public info, it looks like this is a revival of the same basic kind of process as Dow used. But since it's focused on certifying a low GWP for its magnesium, the company will not use sulfur hexafluoride. ("We’re piloting a new generation of electrolytic production technology that is inherently carbon neutral, removing the need for coal and carbon-intense reagents like FeSi and SF6.")<p>They don't say it directly but they also must be using clean electricity for the electrolysis, otherwise the metal would still be fairly CO2-intensive.<p>Unfortunately, the latest news item from their news page is about a threat to their business:<p>"State of Utah denies US Magnesium’s request to extend canals into the Great Salt Lake threatening shutdown of the only American magnesium producer"<p><a href="https://sltrib.pressreader.com/article/6830844853434424" rel="nofollow">https://sltrib.pressreader.com/article/6830844853434424</a><p>[1] <a href="https://ro.uow.edu.au/cgi/viewcontent.cgi?article=2295&context=engpapers" rel="nofollow">https://ro.uow.edu.au/cgi/viewcontent.cgi?article=2295&conte...</a><p>[2] <a href="https://en.wikipedia.org/wiki/Sulfur_hexafluoride#Greenhouse_gas" rel="nofollow">https://en.wikipedia.org/wiki/Sulfur_hexafluoride#Greenhouse...</a>