SALTA, Argentina — Perched 4,000 meters above sea level on the flanks of the Andes, the Hombre Muerto salt flat belies its name as a salt lake: an endless stretch of dry, reddish-ochre earth. Dig as deep as 600 meters and high-concentration brine containing lithium lies below. Like pumping oil, large wells are drilled to draw the brine to the surface.
The Hombre Muerto salt flat holds an average of 921 milligrams of lithium per liter, the highest concentration among Argentina's salt flats. Reserves are estimated at 15 million tons on a lithium carbonate basis, making it a prime asset in both volume and quality. POSCO Holdings first acquired mining rights to Hombre Muerto in 2018 and, through continued exploration, secured 13.5 million tons of lithium resources — six times the initial estimate of 2.2 million tons — before adding 1.5 million tons more with the purchase of mining rights to the Hombre Muerto North salt flat. Factoring in extraction feasibility and yield, roughly 3 million tons of lithium production is expected to be possible. That is enough to make batteries for about 70 million electric vehicles. At current prices of $20,000 a ton, the deposit translates into $60 billion (about 82.8 trillion won) worth of lithium.
Ponds of shimmering emerald water have been built around the salt flat. They function like salt farms, using sunlight to dry and concentrate brine drawn from underground. The salt flats POSCO Holdings has secured cover 287 square kilometers, roughly half the area of Seoul (about 47%) and 99 times the size of Yeouido. Of that, the ponds alone account for 8.92 square kilometers, equivalent to 1,250 soccer fields combined. Several rectangular ponds are grouped into a single string. Three strings have been built so far, with one more under development. Moving from one pond to the next takes about a month, and over three to four months of slowly flowing along this water route, the brine is concentrated to an average of 4,000 milligrams of lithium per liter.
The No. 1 brine lithium plant, which applies POSCO's proprietary lithium extraction technology, produces lithium phosphate near the salt flat in the upstream process, then converts it into lithium hydroxide in the lowland city of Guemes in the downstream process. Lithium hydroxide is used mainly in high-performance electric vehicle batteries. Buyers include the three Korean battery makers, which primarily produce nickel-cobalt-manganese cathode materials. The technology uses electrodialysis to selectively extract lithium and allows phosphoric acid and sulfuric acid, key secondary raw materials, to be recovered and reused during production. It also uses less sodium hydroxide, improving both operational efficiency and cost competitiveness.
The No. 2 brine lithium plant, set for completion in October, applies an improved version of a commercial chemical-based technology validated by leading global companies, raising production stability. This marks the first time POSCO Argentina's No. 2 brine lithium plant, now in the final stages of trial operation, has been opened to Korean media.
Pond concentration takes nine months, somewhat longer than at the No. 1 plant, but requires no secondary raw materials and instead harnesses natural forces such as sunlight and wind, giving it strong cost competitiveness. A downstream plant that will convert lithium carbonate produced at the No. 2 brine lithium plant into lithium hydroxide is under construction at the Yulchon Industrial Complex in Jeollanam-do.
POSCO Holdings has also secured an institutional foundation to underpin the stability of the business. Late last month, POSCO Argentina became the first Korean company to receive final approval under Argentina's Large Investment Incentive Regime, known as RIGI. The approval came just before a summit between President Lee Jae-myung and Argentine President Javier Milei, and was seen as a symbolic example of cooperation between the two countries to strengthen critical resource supply chains. It includes tax benefits exceeding $900 million over 30 years, such as a lower corporate tax rate and tariff exemptions, as well as phased permission to hold export proceeds in foreign currency — measures assessed as a key driver in improving the profitability and funding efficiency of the local business.
On the 31st of last month, aboard his presidential jet en route to Argentina, Lee highlighted the achievement himself on social media, writing that he had heard the lithium development project POSCO Holdings is pursuing in Argentina is named "Sal de Oro," or golden salt, and that he hoped the summit would allow cooperation between the two countries to bear fruit as precious and brilliant as gold. In step with that, POSCO Holdings has moved up its construction timeline for the No. 3 and No. 4 brine lithium plants. Each will have the same capacity as the first two plants, 25,000 tons, with the No. 3 plant targeting investment approval in 2027 and completion in 2030, and the No. 4 plant targeting investment approval in 2030 and completion in 2033. That will give POSCO Holdings a total lithium production capacity of 100,000 tons in Argentina.
POSCO Holdings is also focusing on raising productivity and cutting carbon emissions by adopting artificial intelligence, robotics and renewable energy. The plan is to build AI models and remote robot control systems to replace workers who are vulnerable to altitude sickness in the thin air, achieving both safety and efficiency. The company will also switch the operating power of its high-altitude plant, which goes into full operation next year, from liquefied natural gas generation to solar power, expanding the share of clean energy. That is expected to help meet demands from its end customers, global automakers, to comply with RE100 commitments to use 100% renewable energy.
