The IEA's Global Critical Minerals Outlook 2026 has put a number on the unthinkable: full implementation of China's suspended rare earth controls could put $6.5 trillion per year of downstream production at risk. But a quieter crisis, barely discussed in Washington or Brussels, has already arrived. China's near-total suspension of sulphuric acid exports, triggered by Middle East supply shocks in May 2026, is cascading through copper, lithium, cobalt, and rare earth processing chains, rewriting cost structures and exposing the hidden connective tissue of the global minerals economy.
Introduction
On the morning of June 15, 2026, a logistics manager at a copper cathode facility in Chile's Atacama Desert opened a routine supply report and found a number that made no immediate sense. The price of sulphuric acid, the corrosive workhorse chemical that his operation consumed in staggering quantities to leach copper from oxide ore, had crossed one dollar per kilogram. Three months earlier it had been trading at thirteen cents. He read the figure twice, then called his procurement team in Santiago.
The explanation, when it came, arrived in layers. A war-related closure of the Strait of Hormuz had severed the sulphur trade routes that supply a quarter of global demand. China, scrambling to protect its own fertiliser industry from the resulting shock, had imposed an export quota in January, tightened it through spring, and then on April 10 announced a full export ban on sulphuric acid through the end of August, later extended through December 2026. By June, Chinese acid exports had collapsed by ninety-nine percent in a single month. The logistics manager's operation, which imported roughly a third of its acid from China, was competing for spot cargoes with nickel refiners in Indonesia, battery chemical plants in South Korea, and cobalt processors in the Democratic Republic of Congo, all of whom were simultaneously scrambling for the same vanishing supply.
This is the story that has been almost entirely absent from the headline debate over China's export control architecture. While Washington and Brussels have fixed their gaze on rare earth magnets and graphite anodes, a less-visible chokepoint has already tightened. And the International Energy Agency, in its Global Critical Minerals Outlook released on July 16, 2026, offered the clearest quantification yet of just how much economic value hangs on these concentrated, fragile, and increasingly weaponised supply chains.
The Number That Reframes Everything
The IEA's annual outlook has grown in political weight with each successive edition, as the distance between its warnings and real-world disruptions has narrowed. The 2026 report, released in the middle of a summer defined by export control anxiety, contains a figure that has since migrated into ministerial briefings and boardroom presentations across three continents. Full implementation of China's expanded rare earth measures, the agency calculated, could put an estimated six point five trillion dollars per year of downstream production outside China at risk across the automotive, high-tech, defence, and energy sectors. The United States and Europe would account for nearly half of that economic exposure.
To understand the figure properly requires understanding what it measures. It does not represent the value of rare earths themselves, which are traded in volumes that are, by the standards of global commodity markets, almost modest. It represents the value of everything that rare earths make possible: the electric vehicles whose traction motors depend on neodymium-iron-boron permanent magnets, the wind turbines that require dysprosium and terbium to function at high temperatures, the defence systems whose guidance and propulsion depend on magnets that no Western manufacturer yet produces at adequate scale. As IEA Executive Director Fatih Birol put it when the report was published: "Our latest analysis shows that vast amounts of economic value depend on relatively small volumes of critical minerals, whose supply chains remain highly concentrated and are therefore vulnerable."
The agency's Chief Energy Economist, Tim Gould, was blunter during the media briefing that accompanied the launch. He noted that the IEA had been warning of concentrated supply chain risks for years, but that recent developments had made those dangers "even more salient." The 2026 report's central thesis is stated plainly in its executive summary: "2025 marked the year when the economic risks of highly concentrated supply chains materialised at scale." That sentence was written with the April 2025 rare earth controls in mind. By the time it was published, the sulphuric acid export ban had added a new chapter to the same story.
The battery dimension of the risk carries its own sobering arithmetic. If the trade in battery-grade graphite were fully disrupted, the IEA estimates that more than three hundred billion dollars per year of downstream production outside China would be at risk. China currently controls ninety-four percent of battery-grade graphite processing globally, a share so dominant that, as the report notes, supply outside China is currently projected to meet only around ten percent of 2030 demand. No other major industrial mineral presents this level of near-total external dependency.
The Controls That Sleep But Do Not Die
To appreciate the sulphuric acid disruption fully, it helps to understand the export control architecture that surrounds it, and the particular tension that architecture is generating as the calendar moves toward November 2026. As I reported in September in "Sixty-Two Days: The Rare Earth Truce That Never Really Was," China's sweeping October 2025 rare earth controls, which extended proposed restrictions to internationally-made products containing as little as 0.1 percent Chinese-origin rare earths, remain suspended rather than withdrawn. The deadline for that suspension is November 10, with a second deadline for gallium, germanium, and antimony falling on November 27.
The October 9, 2025 announcement was China's most ambitious use of export controls to date, modelled explicitly on the American Foreign Direct Product Rule and designed to assert regulatory authority across global supply chains rather than merely at China's border. It arrived alongside a parallel set of controls on the battery supply chain: cathode materials, cathode precursors, graphite anode materials, and battery and material production equipment. China dominates eighty percent or more of global midstream and downstream battery supply chains, with shares of ninety-five percent or above in cathode precursor and lithium iron phosphate cathode materials. These controls, too, remain suspended but not withdrawn.
The April 2025 controls, which are not suspended, imposed export licensing requirements on seven heavy rare earth elements: samarium, gadolinium, terbium, dysprosium, lutetium, scandium, and yttrium. Their market impact was immediate and severe. European prices for dysprosium and terbium reached up to six times their Chinese domestic equivalent at the peak. Ford temporarily shut its production line in Chicago in June 2025 due to magnet shortages. Processing times for export licences created backlogs that took months to clear. The IEA report documents that market concentration has actually increased since 2020: for copper, lithium, nickel, cobalt, graphite and rare earth elements, the average market share of the top three refining nations rose to eighty-six percent in 2024 from around eighty-two percent in 2020, with almost all supply growth in most minerals accruing to a single dominant supplier.
The stockpiling arithmetic that the IEA offers in response is striking in its modesty relative to the risk it addresses. The agency recommends that countries work multilaterally to stockpile eleven high-risk materials, requiring an initial purchase of nine point two billion dollars and a net annual cost of nine hundred million dollars. The figures are, as the report observes, "quickly dwarfed" by the potential impact of supply disruptions. Nine hundred million dollars a year is less than one day's worth of the six point five trillion dollar annual downstream risk. The gap between the cost of the insurance and the cost of the catastrophe it would prevent is almost impossible to communicate without sounding alarmist, which may explain why governments have been slow to act on the recommendation.
The Acid Chain: From Smelter Byproduct to Strategic Chokepoint
Sulphuric acid does not appear in most critical minerals policy documents. It is not glamorous. It is not a named element on any national strategic materials list. It is, however, the chemical medium through which much of the world's critical mineral processing actually occurs, and its sudden scarcity in 2026 has exposed a layer of supply chain vulnerability that the policy debate had almost entirely overlooked.
The acid is produced primarily as a byproduct of copper and zinc smelting, which means its geography mirrors the geography of those industries. China, the world's largest copper smelter, produces more than forty percent of global sulphuric acid output, with total domestic capacity in 2025 estimated at approximately 177 million tonnes. For years it was also the largest exporter, supplying Chile, Indonesia, and a range of other acid-importing nations that use it for heap leach copper operations, high-pressure acid leach nickel processing, lithium chemical conversion, cobalt refining, and rare earth separation. The acid does not make headlines. It simply flows, quietly and continuously, into the cost structures of the minerals that do.
The disruption of 2026 arrived from two directions simultaneously. The Strait of Hormuz closed to commercial dry bulk traffic on February 28, severing the routes through which approximately half of global seaborne sulphur trade passes. The Middle East supplies around one quarter of global sulphur, and the closure added thousands of nautical miles and weeks of transit time to any alternative routing. China, facing tighter domestic sulphur supply and rising fertiliser prices, responded by imposing a quota of roughly 700,000 tonnes for the January to April period, equivalent to about forty-five percent of exports in the same period the previous year. Then, on April 10, it announced a full export ban through August, later extended through December.
Will Talbot, raw materials research manager at Benchmark Mineral Intelligence, has been tracking the market consequences with particular attention to battery supply chains. "Sulphuric acid is a vital feedstock for many critical minerals, and the disruption to the sulphur market from the ongoing Middle East conflict has had knock-on effects across key markets," he said. "The outstanding risk is that more critical minerals players cut production or even shut down operations entirely." The price data supports his concern. Acid that traded at between thirteen and seventeen cents per kilogram through February 2026 had crossed a dollar per kilogram within two weeks of the May export suspension taking effect, and by July was holding in a range of one dollar twenty-six to one dollar forty-two per kilogram. That represents a price increase of eight to ten times pre-crisis levels, sustained over months rather than resolved in days.
The cost impact on lithium processing is perhaps the starkest illustration of the acid chain's newfound strategic importance. Benchmark analysis found that sulphuric acid previously represented approximately three percent of the cost of producing lithium chemicals from hard rock spodumene sources. By mid-2026, it accounted for twenty-two percent of total hard-rock lithium conversion costs and had become, in Benchmark's characterisation, "the single most volatile and material input" in lithium processing. Battery-grade lithium carbonate prices in China had risen approximately sixty-five percent in US dollar terms year-to-date. The IEA's own report acknowledged the phenomenon directly, noting that China's move to curb sulphuric acid exports in May 2026 had led to its cost overtaking energy costs in the production of several critical minerals.
Geography of Pain: Chile, Indonesia, and the DRC
The geography of the sulphuric acid crisis maps almost perfectly onto the geography of the world's most strategically important mineral production. Chile, which received approximately thirty-two percent of China's acid exports in 2025, is now competing for spot cargoes at prices above four hundred and forty dollars per tonne. Roughly twenty percent of Chile's copper output depends on acid-intensive heap leaching, and the operations most exposed are the oxide deposits in the north of the country, which have no alternative processing route available. "A long-lasting ban could impact copper cathode production in Chile," said Yuya Pan, an energy and commodities analyst at S&P Global. Sarah Marlow, acid editor at Argus, was more explicit about the pricing dimension: "If the suspension is enforced for the full year, the Chileans will be faced with even higher prices than we are seeing today." Peter Harrisson, an acid analyst at CRU, noted that replacing Chinese export volumes under current market conditions is nearly impossible.
Indonesia presents a structurally distinct but equally acute problem. The country now accounts for more than sixty percent of global nickel production, dominated by high-pressure acid leach facilities that require sulphuric acid produced on-site from imported sulphur. Indonesia imports approximately seventy-five to eighty percent of its sulphur from the Middle East, the same supply routes severed by the Strait of Hormuz closure. Its dependency on Chinese acid was already growing rapidly: Indonesia's share of China's acid exports rose from fifteen percent in 2025 to twenty-eight percent in the January to May 2026 period, suggesting that HPAL capacity was expanding faster than the country's ability to source acid from alternative origins. The export ban caught Indonesian operations at a point of maximum exposure.
HPAL plants cannot operate at partial capacity. They are, as one industry observer puts it, on or off. Indonesian buyers are now competing with Chilean copper producers for smelter acid byproduct from Japan and South Korea, markets that have limited spare capacity to absorb both demand streams simultaneously. If Indonesian HPAL output is constrained by acid scarcity, the resulting nickel sulphate shortfall transmits directly into battery cathode manufacturing, ultimately affecting the cost and availability of EV battery cells globally. Nickel processing in Indonesia involves major players including Tsingshan, and disruptions at this stage ripple forward toward battery manufacturers including CATL.
In the Democratic Republic of Congo and Zambia, where copper-cobalt hydrometallurgical operations require on the order of two million tonnes of acid per year, domestic smelter byproduct supply covers only a fraction of that demand. Even at fifteen to twenty percent of cash costs, acid pricing has been sufficient to meaningfully shift the cost curve for solvent extraction-electrowinning copper operations. Sasa Jarvis, a mining partner at McMillan LLP, observed that the acid disruption could "quietly reshape metals markets" in ways that policy discussions had not anticipated, particularly given the simultaneous shipping risks through the Strait of Hormuz. The word "quietly" is doing significant work in that sentence. Benchmark estimates that more than half of global lithium, cobalt, rare earth, and purified phosphoric acid production expected in 2026 is exposed to sulphur and sulphuric acid disruptions. For high-purity manganese sulphate monohydrate, used in manganese-containing batteries, the exposure is effectively one hundred percent.
The Structural Trap: Refining Concentration and the Limits of Optimism
The sulphuric acid episode illuminates a broader structural problem that the IEA report documents with unusual directness: the diversification of critical mineral supply chains has been concentrated overwhelmingly in mining, while refining and downstream processing have remained as Chinese-dominated as ever. Mining capacity is expanding across diverse regions, the report notes, but refining and downstream manufacturing capacity remains limited. In the rare earth sector, announced mining projects outside China could deliver nearly 50,000 tonnes of capacity by 2035, yet planned refining and separation capacity outside China amounts to under 40,000 tonnes, primarily in Malaysia and the United States. Downstream magnet capacity is even more constrained, totalling only around 18,000 tonnes on a rare earth content basis. The IEA's conclusion is pointed: "Diversification focused solely on mining could shift dependence on China for critical minerals down the value chain rather than reducing it."
The investment picture compounds the concern. Critical minerals investment fell by nine percent in 2025, the first substantial decline since 2020. Battery materials specialists drove the decline, with investment falling twenty percent overall and lithium specialists cutting investment by around forty percent after several years of strong growth. Exploration spending dropped more than ten percent, with lithium and nickel seeing approximately forty-five percent declines. Public finance commitments in advanced economies reached around sixty-five billion dollars in 2025, more than four times the 2023 level, but the IEA notes a considerable gap between commitments and actual disbursements. Birol has begun framing the cost of diversification as a "mineral security premium," positioning higher supply chain costs as a form of economic insurance rather than market failure. Whether governments will accept that framing in the face of inflation and fiscal pressure remains one of the central uncertainties of the policy moment.
China, meanwhile, has not been standing still. The IEA estimates that Chinese firms invested roughly one hundred and twenty billion dollars between 2023 and 2025 in foreign mining operations, as well as over fifteen billion dollars in domestic ore exploration in 2024. Even as China restricts exports, it continues to extend its reach over the upstream assets that feed the processing infrastructure it has spent thirty years building. The extraterritorial scope of the October 2025 controls, which would require export licences for foreign-made products containing as little as 0.1 percent Chinese-origin rare earths, represents a logical extension of that strategy: not merely to control what China produces, but to regulate what the world makes with Chinese materials. Last month, Beijing added ten American companies to its export controls list, including rare earth miners and defence contractors, framing the move as a national security measure. The escalation pattern continues to be methodical and cumulative.
The sulphuric acid export curbs occupy a different register in this architecture. Beijing's stated rationale was domestic food security, not geopolitical leverage. Lynn Song, chief economist for Greater China at ING Bank, noted that administrative controls would effectively suspend acid exports from May 2026, emphasising that the contribution of such exports to gross domestic product was far less important than broader food security objectives. That explanation may be entirely sincere. It is also, from the perspective of a copper cathode plant in the Atacama or a nickel refinery in Sulawesi, functionally indistinguishable from a deliberate export restriction. The effect on global mineral processing is the same regardless of intent.
Conclusion: The Acid Test We Were Not Prepared For
On a Tuesday morning in mid-July 2026, a procurement officer at a hard-rock lithium conversion plant in Western Australia completed a quarterly cost review and submitted a budget revision to management. The revision, which ran to eleven pages, contained a single line that captured the past six months with brutal economy: sulphuric acid, previously three percent of conversion costs, now twenty-two percent. The document recommended that the company begin exploring alternative processing routes, a recommendation that the engineering team had already informally concluded would take at least three years to implement at commercial scale. In the meantime, the plant would continue operating, absorbing costs that had not existed in any model built before February 2026.
The IEA's six point five trillion dollar figure is useful precisely because it converts an abstract supply chain argument into a number that finance ministers and chief executives can hold in their hands. But the sulphuric acid episode suggests that the biggest risks in critical mineral supply chains may not be the ones that appear in the scenarios being modelled. The rare earth magnet controls were anticipated for years; entire policy frameworks were constructed around managing their eventual arrival. The acid export ban arrived through a combination of Middle East conflict, domestic Chinese agricultural politics, and the physical chemistry of copper smelting, a causal chain that almost no critical minerals analyst had placed near the top of their risk register.
Fatih Birol, in his foreword to the July report, noted that while diversified supply can come at a higher cost, this should be understood as "a mineral security premium in a time of geopolitical uncertainty, a form of economic insurance against major supply risks." The phrase is carefully chosen. Insurance is most valuable when the risk being insured against is not the one you were expecting. The logistics manager in the Atacama, the procurement officer in Western Australia, and the HPAL plant manager in Sulawesi are all, right now, paying a premium for a risk that nobody had properly priced. The question the IEA report leaves unanswered, and that the next several months will begin to answer, is whether the world's governments will act on the lesson before the next unexpected chokepoint closes.