Latrobe targets US magnesium supply gap

US Magnesium later sought authority to sell, transfer or abandon remaining assets at the site. Those assets included magnesium metal, brine, salt and equipment.

The US Geological Survey (USGS) said the Utah operation recovered primary magnesium from Great Salt Lake brines. Output fell sharply after equipment failures in September 2021. Limited production then ceased in 2022.

Domestic magnesium production went offline

USGS reported no primary magnesium production in 2023-25. Meanwhile, USGS estimated reported primary consumption at 40,000 metric tons in 2025.

Imports for consumption totaled 77,900 metric tons in 2025, including waste and scrap, magnesium-bearing alloys, and semi-fabricated magnesium, according to the USGS 2026 second-quarter Mineral Industry Survey. Magnesium metal imports totaled 19,800 metric tons, accounting for about a quarter of the total imports for consumption.

Net import reliance exceeded 75% in 2025, according to the USGS, while the domestic share came from 26,000 metric tons of secondary magnesium recovered from old scrap.

Trade cases reshaped primary magnesium supply

Latrobe said China accounts for about 90% of global primary magnesium supply. China’s share does not translate into a similar share of US imports.

US antidumping and countervailing duties have restricted Chinese magnesium metal imports, although China remains a source of magnesium scrap.

Israel also previously supplied a significant share of US magnesium metal imports. US Magnesium later petitioned for antidumping and countervailing duties on imports from Israel. The US Commerce Department recommended a 219% duty rate, and importers faced provisional cash deposit requirements while the case remained pending.

The US International Trade Commission ultimately voted against imposing the duties in late 2019. By then, the trade flow had changed. US imports of unwrought magnesium containing at least 99.8% magnesium from Israel decreased about 90% heading into 2020 and subsequently ceased.

The composition of magnesium imports has also shifted. Metal containing less than 99.8% magnesium now accounts for most metal imports, according to Commerce Department data, after higher-purity metal made up a larger portion of the trade in earlier years.

In 2025, the US imported nearly eight times as much magnesium metal containing less than 99.8% magnesium as metal at or above 99.8%. South Korea supplied slightly more than 60% of the lower-purity imports. The remaining supply was fragmented, with no other country accounting for more than 10% of the year’s volume.

Magnesium scrap provided another source of imported material. Scrap imports in 2025 exceeded the combined volume of both magnesium metal categories. More than two-thirds originated from Canada, China or the Czech Republic.

LOIs cover 64% of Phase 1 capacity

Latrobe has letters of intent (LOI) covering 32,000 metric tons per year. The volume equals 64% of Phase 1 nameplate capacity. The LOIs are nonbinding and are intended to convert into binding offtake agreements alongside project financing.

Metal Exchange accounts for 25,000 metric tons of the announced LOI volume. The company has served as Latrobe’s US distribution partner since 2019. Meridian Lightweight Technologies signed an LOI for 5,000 metric tons. Twin City Die Castings signed one for 2,000 metric tons.

Latrobe also reported North American customer inquiries for up to 110,000 metric tons per year. It described those inquiries as indicative expressions of interest rather than commitments. Global inquiries totaled 285,000 metric tons per year.

The proposed plant would produce 99.9% pure magnesium metal and magnesium alloys for casting and extrusion.

Imported slag would feed the South Carolina plant

Latrobe’s proposed route differs from the brine-based US Magnesium operation. The company plans to use ferronickel slag containing about 33% magnesium oxide. The slag would come from Société Le Nickel (SLN), an Eramet company, in New Caledonia.

Latrobe estimates the South Carolina plant would require about 340,000 metric tons of slag per year. Its binding memorandum of understanding with SLN runs for 20 years from 2026. Latrobe said the agreement includes options that can cover its modelled 30-year project life.

SLN holds an estimated 28 million metric tons of existing ferronickel slag, according to Latrobe. Latrobe also said SLN can generate about 1.8 million metric tons annually.

Latrobe plans to combine its hydrometallurgical process with a thermal reduction process. Its Australian demonstration plant has produced sustained magnesium oxide and other saleable byproducts. Full magnesium metal production there was still expected to begin in the second half of 2026.

South Carolina site selection and operating costs

Latrobe cited port access, rail service, state support and competitive energy costs as reasons for the site selection.

Energy accounts for 22% of Latrobe’s estimated operating cost. The company said Coastal Electric Cooperative has confirmed adequate electrical capacity for the preferred site. Dominion Energy has confirmed sufficient natural gas capacity, according to Latrobe. Supply connections remain under negotiations.

Latrobe estimates reagents will account for 59% of operating costs, while freight and logistics will account for 12%. The preferred site has access to the Port of Charleston and rail infrastructure. Port access matters because the project would import its ferronickel slag.

Maintenance and labor are anticipated to account for the remaining 7% of operating costs.

South Carolina has proposed tax incentives plus cash and in-kind support for the project. The package remains subject to the site purchase and final approvals from the county and state.

Financing the final investment decision

Latrobe estimates it needs $30 million before a final investment decision. The money would cover the feasibility study and land acquisition.

On Sept. 17, Latrobe said it received a nonbinding letter of support for $15 million of equity funding. The funding would go toward the feasibility study. It is conditional on Latrobe receiving another $15 million from a specified US-based entity.

The company estimates total capital costs for construction at $1.1 billion to $1.5 billion. Latrobe derived it from a Bechtel pre-feasibility study for a 100,000-metric-ton international plant. It then adjusted the estimate for a 50,000-metric-ton US project. The company included a 40% contingency for cost uncertainty associated with the early-stage estimate.

The feasibility study is targeted to start by the end of the first quarter of 2027, and is expected to take 12 months. Permitting is targeted to start by the third quarter of 2027 and the company is targeting a final investment decision for March 2028. First production is projected to begin April 2030.

Magrathea advances a second US magnesium supply project

Latrobe is not alone in pursuing new US primary magnesium capacity. California-based Magrathea Metals is developing an electrolytic process to produce magnesium metal from seawater and brines.

Magrathea signed a supply agreement with Cargill in April 2025 for seawater-derived feedstock for its pilot operations. The company later commissioned a 2-metric-ton-per-year research and development pilot plant in Oakland, Calif. Magrathea said the pilot produced magnesium metal with purity above 99.9%.

The company installed its magnesium chloride electrolyzer at the Oakland facility in May 2025. The system uses electricity to split magnesium salts to produce magnesium metal. Magrathea said it planned to use pilot data to develop a commercial-scale plant.

The US government has also supported the development. Magrathea received $19.6 million through the Defense Production Act Title III program in February 2024. A magnesium sample produced at the pilot facility met the program’s purity target in 2025.

Magrathea has since moved toward a commercial project in southwestern Arkansas. The company and TETRA Technologies formed a joint venture called Arkansas Magnesium to develop a plant at TETRA’s Evergreen chemical complex.

Magrathea said in May that it had raised $24 million in a Series A financing round, bringing its total backing from private investment, government funding and commercial partnerships above $100 million. The company also reported memorandums of understanding covering more than $500 million per year in potential future metal sales.

Latrobe would approach the same US primary magnesium supply gap differently. Its South Carolina project would process imported ferronickel slag through hydrometallurgical and thermal reduction processes. Magrathea instead plans to produce magnesium from brine through electrolysis.