As the US-Israel war in Iran drags into its third month, sulphuric acid – a chemical ingredient critical for fertiliser production and metal processing that has seldom grabbed global headlines – has become a keenly watched commodity.
The military conflict in the Gulf and the effective blockage of the Strait of Hormuz initially triggered a squeeze on sulphuric acid, with prices on the rise after shipments in the region – which accounts for a quarter of global production – were largely stalled since military strikes began on February 28.
But the second shock wave came after reports surfaced of an export ban on sulphuric acid from China that would take effect in May. The country accounted for 45 per cent of the nearly 10 million tonnes of the chemical shipped from Asia last year and about 23 per cent of global exports.
As the putative start date approaches, overseas buyers in industries ranging from fertiliser to battery manufacturing are struggling to find a substitute, and many wonder whether similar freezes are being planned.
This, analysts said, would have “significant implications” for the chemical’s global supply and prices, but also serves to show China had quietly made itself a “linchpin” in the trade of sulphuric acid, as well as other critical metals and chemicals.
David Argyle, partner of Arlington Innovative Partners, which focuses on critical minerals and advanced manufacturing supply chains, said that China has done “a very good job” growing its economy within the global framework.
Total export value of China’s sulphuric acid last year reached US$290 million, according to the Observatory of Economic Complexity data platform. The main destinations for these shipments included Chile, Indonesia, Saudi Arabia, Morocco and India. In 2024, the total export value of China’s sulphuric acid was US$349 million, with the United States being one of the top importers.
For the first three months of this year, China’s sulphuric acid exports dropped to 528,000 tonnes, according to customs data, a 50 per cent decrease from the same period last year.
“China’s main priority has tended to be food security and hence the domestic fertiliser industry,” said Sarah Marlow, global editor for fertilisers at Argus Media. “Sulphur and sulphuric acid are crucial raw materials for the production of phosphate fertilisers.”
China already imposed export quotas to around 700,000 tonnes for January to April before the ban was reported, just over half the volume exported versus the same period last year, according to Peng Yang, founder and managing director at Moco Tech which focuses on chemical, fertiliser and petrochemical engineering.
“What has happened is that – around April 9 to 10, several sulphuric acid producers and smelters in China received internal notifications (or directives), telling them to stop exporting the by-product acid from copper and zinc smelting,” Peng said.
“The [reported ban] goes further: it stops exports outright to prioritise domestic needs, especially fertiliser production, amid global sulphur supply disruptions from the Iran war and Strait of Hormuz issues,” he added. “The restriction is expected to last through at least the end of 2026, or until domestic priorities ease.”
He noted that at least one major international buyer was directly informed of the change by its Chinese supplier.
So far the Chinese government has kept silent regarding the anticipated measure. The Ministry of Commerce did not immediately respond to a faxed request for confirmation of the ban.
An export suspension could remove at least 3 million tonnes from the seaborne market if it is fully implemented, according to Argus Media, as China exported 3.33 million tonnes of sulphuric acid from May to December.
“There are no meaningful substitutes to the loss of Chinese supply, given that China is also the world’s largest sulphuric acid exporter,” it said in a report released on April 14. “Most volumes came from China, South Korea and Japan.”
Sulphuric acid is the core raw material for the production of phosphatic fertiliser, which directly determines the grain yield for agricultural land, according to the Hangzhou-based Sunsirs Commodity Data Group.
“When the cost of upstream raw materials doubles, fertiliser factories can only raise prices, and in the end, these costs will all be reflected in the weight of the vegetables in the market,” it explained.
The export restriction is a “key constraint” on global supply, Peng noted, adding it would have downstream effects on related products such as monoammonium phosphate (MAP) and diammonium phosphate (DAP) – fertilisers which use sulphuric acid in their first steps of production.
Other low-grade fertiliser products such as single superphosphate and nitrogen-phosphorus-sulphur will also see an impact, he said.
The spot price of sulphuric acid had risen to nearly 1,800 yuan (US$263) per tonne as of Tuesday, according to market researcher SunSirs, surging from below 1,000 yuan per tonne in January.
A ban on the chemical could have motives aside from food security, already a major priority.
The reported restriction could be part of a “national project” intended to secure raw materials and technology for batteries exported from China because the chemical is also used in lead-acid car batteries, said a company executive, who asked for anonymity due to the sensitive nature of the issue.
There is an expectation that more chemicals and raw materials related to the battery trade might be banned in the future if deemed necessary, the person added.
While sulphuric acid is most commonly used to manufacture fertiliser, a shortage would also disrupt copper, nickel and silver mining operations, particularly those which rely on hydrometallurgical processing, or leaching.
Sulphuric acid is an essential input for the copper mining industry, crucial to extracting copper from oxide and low-grade ores. The chemical is also used for extracting nickel from laterite ores to create battery-grade nickel.
Amid heightened global geopolitical tensions, China has even more cause to prioritise the stability of its strategic materials, elevating the supply and domestic stockpiling of critical resources to a matter of national security.
China’s near-monopoly on the supply and refining capacity for rare earth elements has already provided an advantage in its wide-ranging rivalry with the United States; the export controls Beijing enacted on the minerals helped to bring last year’s heated bilateral trade war to an uneasy peace, and the metals continue to be a major sticking point in the technological arms race between the world’s two largest economies, as they are vital components in a number of advanced products.
Zheng Shanjie, head of the National Development and Reform Commission (NDRC), earlier this week warned external risks were mounting and said China had to reinforce its strategic reserves and response capabilities.
“The evolution of the international situation is profoundly affecting China as we enter a period where strategic opportunities coexist with risks and uncertainties,” Zheng wrote in an article published on Monday in Communist Party mouthpiece People’s Daily.
The American Chamber of Commerce in China said last week that US enterprises operating in China lauded improvements in the country’s regulatory environment and “openness”, but long-standing concerns over access and Beijing’s emphasis on security continue to weigh on optimism, with expectations for US President Donald Trump’s looming China visit also muted.
Western original equipment manufacturers are also worried about the ripple effect of a sulphuric acid export ban, according to Argyle of Arlington Innovative Partners. Some, he said, have started to question whether magnesium will be the next element suspended.
“There’s already some partial restrictions of magnesium,” he added. “China now needs magnesium for advanced engineered equipment – cars, computers, robotics.”
Chinese researchers said in 2023 that they had developed supersized magnesium alloy auto parts that could significantly reduce the cost of making cars and promote lightweight vehicle designs.
“So why would you sell a semi-finished product?” Argyle asked. “Why would China sell a product that they can use themselves and actually create more [gross domestic product]?”
China’s primary magnesium production accounted for over 90 per cent of the global supply in 2025, according to industry data platform Shanghai Metals Market, with foreign buyers accounting for 40 to 45 per cent of the country’s output. -- SOUTH CHINA MORNING POST
