China has slammed the brakes on sulphuric acid exports to Chile, delivering a severe blow to the world’s largest copper producer and raising fears of significant production cuts in the critical red metal.
In a dramatic development, Chinese customs data reveals that sulphuric acid shipments to Chile collapsed to zero tonnes in March 2025 — the first total cutoff in nearly two years. The South American nation, which relies heavily on the chemical to produce roughly half of its refined copper, now faces an acute supply crunch at a time when global copper demand is surging.
Just weeks earlier, China had shipped 31,870 tonnes to Chile in February. One year ago, in March 2024, that figure stood at a robust 151,268 tonnes. The sudden halt has sent shockwaves through Chile’s mining industry.
The crisis stems from a toxic combination of geopolitical tension and domestic priorities in China. The ongoing war in the Middle East has triggered a global sulphur shortage, forcing Beijing to protect its own fertiliser industry. Reports now indicate China is preparing to impose a complete ban on sulphuric acid exports starting in May 2025.
Chile, which was China’s single largest overseas customer for the acid, is being hit hardest. The country lacks sufficient domestic production and has depended on Chinese imports for 37% of its total sulphuric acid supply.
Sulphuric acid is the unsung hero of Chile’s copper industry. It is essential for the leaching process used to extract copper from oxide ores and secondary sulphides — a method responsible for approximately 1.1 million tonnes of Chile’s refined copper output each year.
Analysts are sounding the alarm. Morgan Stanley warned that Chile’s entire annual leached copper production of 1.1 million tonnes could be under threat. That represents over half of Chile’s total refined copper output and nearly one-fifth of its overall copper production of 5.5 million tonnes.
Alexis Urbani, a sulphuric acid trader at Incotrade Chile, didn’t mince words:
“If sulphur supply tightens, acid availability becomes more constrained and expensive. That can directly impact cathode production, especially for operations relying on secondary sulphides or lower-grade ores, where acid consumption is higher.”
Bold Baatar, Chief Commercial Officer at Rio Tinto and co-owner of the giant Escondida mine, was equally blunt, telling a conference this week:
“The most exposed country is Chile in terms of need for sulphuric acid imports, because that’s where the highest amount of leached copper is.”
As China redirects its remaining acid exports to countries like the Philippines, India, and Indonesia, Chile is scrambling to secure alternative supplies in an increasingly tight global market. Higher costs and potential delays now loom over some of the world’s most important copper mines.
With the world racing toward net-zero goals and explosive demand for copper in EVs, renewables, and AI infrastructure, any disruption to Chilean supply could have far-reaching consequences for global copper prices and the clean energy transition.