Workers service a brine-extraction well at the Hombre Muerto salt lake in the highlands of Salta, Argentina.
SALTA, Argentina — The Hombre Muerto salt flat, set high in the foothills of the Andes at 4,000 meters above sea level, stretches out as endless dry, reddish-ochre earth, belying its name as a “salt lake.” As deep as 600 meters underground lie deposits of highly concentrated brine containing lithium. Just as oil is pumped up, large wells for extracting groundwater are drilled to draw the brine to the surface.
The Hombre Muerto salt flat holds an average of 921 milligrams of lithium dissolved per liter, the highest concentration among Argentina’s existing salt flats. Reserves are estimated at 15 million tons on a lithium carbonate basis, making it a prime asset in both quantity and quality. After POSCO Holdings (005490.KS) first acquired the mining rights to the Hombre Muerto salt flat in 2018, continued exploration secured 13.5 million tons of lithium resources — six times the initial estimated reserves of 2.2 million tons — and the additional purchase of the mining rights to the Hombre Muerto North salt flat added another 1.5 million tons. Factoring in mining feasibility and yield, production of about 3 million tons of lithium is projected, enough to make batteries for roughly 70 million electric vehicles. At current prices of $20,000 per ton, that amounts to a simple calculation of $60 billion (about 82.8 trillion won) worth of lithium.
Around the salt flat, ponds of shimmering emerald-green water have been built. They function like salt-drying fields, evaporating and concentrating brine that has pooled underground by exposing it to sunlight. The salt flats POSCO Holdings has secured cover a total area of 287 square kilometers — about half the size of Seoul (roughly 47%) and 99 times the size of Yeouido. Of that, the ponds alone span 8.92 square kilometers, equivalent to 1,250 soccer fields combined. Several rectangular ponds together form one string. Three strings have been built, 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 the water course, the brine is concentrated to an average lithium content of 4,000 milligrams per liter.
The first brine lithium plant, which applies POSCO’s independently developed “POSCO-type lithium extraction technology,” produces lithium phosphate (LP) near the salt flat (upstream process) and then converts it into lithium hydroxide in the lower-lying city of Güemes (downstream process). Lithium hydroxide is used mainly in high-performance electric-vehicle batteries. The demand comes from South Korea’s three battery makers, which mainly produce NCM (nickel, cobalt, manganese) cathode materials. The technology selectively extracts lithium using the principle of electrodialysis and allows phosphoric acid and sulfuric acid, key subsidiary raw materials, to be recovered and reused during production. It is also notable for using little sodium hydroxide, improving both operational efficiency and cost-effectiveness.
The second brine lithium plant, set for completion this October, has enhanced production stability by adapting a commercialized chemical-based technology verified by leading global companies. This marks the first time POSCO Argentina’s second brine lithium plant, now in the final stages of trial operation, has been shown to South Korean media.
Its pond-concentration period of nine months is somewhat longer than the first plant’s, but it offers strong cost-effectiveness by harnessing natural forces such as sunlight and wind without adding subsidiary raw materials. The downstream plant that converts the lithium carbonate produced at the second brine lithium plant (upstream process) into lithium hydroxide is being built at the Yulchon Industrial Complex in South Jeolla Province.
Artificial ponds are set up at the Hombre Muerto salt lake in the highlands of Salta, Argentina. The ponds concentrate underground brine by drying it in the sun.
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 from the Argentine government under its Incentive Regime for Large Investments (RIGI). Coming just before a summit between President Lee Jae-myung and Argentine President Javier Milei, it was cited as a symbolic example of cooperation between the two countries to strengthen critical-resource supply chains. The measure is seen as a key driver for boosting the profitability of the local business and the efficiency of its fund management, including more than $900 million in tax benefits over 30 years, such as corporate tax cuts and tariff exemptions, as well as permission to hold export proceeds in foreign currency on a phased basis.
Aboard the presidential jet heading to Argentina on the 31st of last month, President Lee personally highlighted the achievement through social media, saying he had heard that the name of the lithium development project a Korean company (POSCO Holdings) is pursuing in Argentina is “Sal de Oro,” or “golden salt,” and that he hoped the cooperation between the two countries would, like gold, bear precious and shining fruit through the summit. In step with this, POSCO Holdings has also moved up its construction schedule for the third and fourth brine lithium plants. Each will have the same production capacity as the first and second plants at 25,000 tons; the third plant is targeted for investment approval in 2027 and completion in 2030, and the fourth for investment approval in 2030 and completion in 2033. This will give POSCO Holdings a total lithium production capacity of 100,000 tons in Argentina.
POSCO Holdings is also focusing on introducing artificial intelligence (AI), robotics and renewable energy to raise productivity and cut carbon emissions. The plan is to catch two birds with one stone — safety and efficiency — by building an AI model and a remote robot control system to replace workers who are prone to altitude sickness in the low-oxygen environment. It will also expand the share of clean energy by switching the operating power for the high-altitude plant, which goes into full operation next year, from existing liquefied natural gas (LNG) generation to solar power. Through this, the company expects to be able to meet the RE100 (100% renewable energy use) requirements of its end customers, the global automakers.