When President Trump signed a preliminary ceasefire agreement with Iran on the sidelines of the G7 summit in June 2026, the immediate headlines focused on nuclear timelines and frozen assets. But buried in the 14-point memorandum was a provision with profound consequences for the global critical minerals industry: the reopening of the Strait of Hormuz, through which roughly half of the world's seaborne sulfur trade flows. For mineral processors from Chile to Indonesia who had spent four months rationing their most essential chemical input, the deal's significance had little to do with uranium enrichment.
Introduction
The dinner at the Palace of Versailles on the evening of June 17 was, by most accounts, a moment of considerable theatre. President Donald Trump sat across from French President Emmanuel Macron in one of the world's most ornate dining rooms, having just spent two days at the G7 summit in nearby Evian-les-Bains negotiating commitments on rare earth supply chains and dependency targets. What he signed over dessert, according to accounts from multiple officials present, was something none of the summit's official agenda items had anticipated: a 14-point memorandum of understanding with Iran committing both countries to a 60-day ceasefire, a framework for nuclear negotiations, and the reopening of the Strait of Hormuz.
The headlines the following morning concentrated on the geopolitics: the $300 billion reconstruction fund, the promise of sweeping sanctions relief, the question of whether Iran's nuclear programme could be meaningfully constrained within sixty days. What received considerably less attention was the immediate downstream consequence for a stretch of industrial chemistry that underpins the production of nearly every critical mineral the West has spent the past two years scrambling to secure.
For four months, since Iranian Revolutionary Guard Corps forces began boarding merchant vessels and laying sea mines in the strait's narrow 34-kilometre passage, roughly half of the world's seaborne sulfur trade had been effectively frozen. Sulfur, a byproduct of petroleum refining that few outside the chemicals industry think about, is the primary feedstock for sulfuric acid, the single most produced industrial chemical on earth and the essential reagent for processing lithium, nickel, copper, cobalt, and rare earths. When the strait closed, the economics of critical mineral processing did not merely tighten. In some corners of the market, they collapsed.
The Chokepoint Nobody Planned For
On February 28, 2026, the day the United States and Israel launched air strikes against Iran and assassinated Supreme Leader Ali Khamenei, the Strait of Hormuz was carrying approximately 20 million barrels of oil per day, representing roughly a fifth of global seaborne energy trade. What virtually no emergency planning document had adequately modelled was what would happen to the sulfur that travelled alongside it.
Middle Eastern oil refineries generate approximately 70 percent of the world's elemental sulfur as a byproduct of petroleum processing. About a quarter of global sulfur supply originates in the region, and roughly half of the world's seaborne sulfur trade passes through the strait. When Iran closed the waterway and the United States simultaneously blockaded Iranian ports from April 13 onward, major shipping lines including Maersk, CMA CGM, and Hapag-Lloyd suspended transits entirely. Sulfur, which had no internationally coordinated strategic reserve and no emergency release mechanism equivalent to the International Energy Agency's oil protocols, simply had nowhere to go.
The price response was swift and severe. According to CSIS analysts writing in June 2026, sulfur prices rose by more than 50 percent from the outbreak of the conflict, while sulfuric acid prices more than doubled in some regional markets. The Soufan Center had noted as early as March 25 that since the start of Operation Epic Fury, sulfur prices had nearly doubled; The Oregon Group documented spot prices for sulfuric acid tripling in certain markets. Gaurab Chakrabarti, co-founder of the US-based chemical manufacturer Solugen, distilled the crisis in a post on X that circulated widely through the industry: "Sulfur, semiconductors, food. Three supply chains, one 21-nautical-mile chokepoint, and zero domestic alternatives at scale."
The compound effect was worse than any single price spike suggested. Beijing, citing domestic industrial needs and strategic security, responded to the Hormuz closure with a unilateral ban on all sulfuric acid exports, stripping countries that had relied on Chinese acid as a backup supply of their last available buffer. Jack Lifton, co-chair of the Critical Minerals Institute, described the combined impact with characteristic bluntness. Sulfuric acid, he said, is "one of the key reagents in all processing of metals, minerals, and the manufacturing of chemicals," and China's export restriction was going to have a "tremendous impact on the non-Chinese chemical industry and metal processing industry." He was not wrong.
Acid Test: How the Shortage Hit the Mine Floor
The consequences moved quickly from commodities markets to physical operations. Indonesia, the world's largest nickel producer, sources approximately 75 percent of its sulfur from the Middle East. By April, several Indonesian nickel processors had begun limiting output. High-Pressure Acid Leach plants, the dominant industrial pathway to battery-grade nickel sulphate for electric vehicle batteries, consume enormous quantities of sulfuric acid at every stage of the laterite ore processing cycle; with acid scarce and expensive, the economics of the entire pathway deteriorated.
In Chile and Peru, copper mines began rationing their most critical chemical input. Chile produces roughly 1.1 million tonnes of refined copper per year through solvent-extraction leaching of oxide ores, a process entirely dependent on sulfuric acid. The Democratic Republic of the Congo, the world's second-largest copper producer and the dominant source of cobalt, saw its processing economics similarly squeezed. Fertilizer plants in India and Brazil scrambled for alternative suppliers and found few. As Vijay Chakravarthy, chief risk officer at Louis Dreyfus Company, told the Financial Times, industrial uses of sulfur such as copper smelting and nickel production command higher monetary value than fertilizer production, meaning agricultural processors found themselves "at the back of the queue."
The scale of output reduction was not trivial. Industry analysts estimated that sulfur shortages were already driving 20 to 30 percent output reductions for critical mineral processors in the most affected regions by the time the ceasefire was announced. Lynas Rare Earths, one of the few significant rare earth producers outside Chinese control, reported a 20 percent production miss at its new Kalgoorlie processing facility and specifically cited sulfur shortages as a constraint factor. A company that had been positioned as a cornerstone of Western rare earth supply chain resilience was, in effect, being undermined by a maritime crisis on the other side of the Indian Ocean.
The CSIS analysts who quantified the price spikes were careful to note the systemic logic underlying them. Sulfuric acid, they observed, is a key input not only in nickel and copper processing but also in lithium refining and rare earth separation, meaning that "price spikes have immediate implications for production economics" across virtually every mineral category that Western governments had spent two years designating as strategically critical. The Oregon Group had made the same point with stark precision months earlier: "If you wanted to look for a single point of failure across such a broad range of metals produced, sulfuric acid would be that single point of failure."
What the MOU Unlocks: Relief and the Iranian Mineral Opportunity
The immediate significance of the ceasefire for critical mineral supply chains is, in the near term, largely about price relief rather than new supply. CSIS analysts writing on June 18, the day after the Versailles signing, were direct on this point: the reopening of the strait "should help bring down sulfur and sulfuric acid prices, which have sharply increased the costs across critical mineral supply chains." The physical logic is straightforward. With shipping lanes reopened and the American blockade of Iranian ports lifted, Middle Eastern sulfur production that has been unable to reach Asian and South American buyers will begin moving again. The supply tightness that drove prices to crisis levels should ease, though the speed and completeness of the recovery will depend on how durably the ceasefire holds.
That durability is not guaranteed. On June 20, just three days after the Versailles signing, Iran announced the closure of the strait again, citing Israeli actions as a violation of the MOU's terms, a claim the US military denied. The episode illustrated what CFR analysts have called the deal's fundamental character: it is "just a start, creating a process for opening the Strait of Hormuz in the short run and laying out a sixty-day timetable to address many of the remaining issues." For mineral processors who had hoped to immediately recommit to long-term procurement contracts, that volatility introduces a complication that price relief alone cannot resolve.
The longer-term opportunity, however, is more structurally significant. CSIS analysts noted that the ceasefire agreement "may offer an opportunity to advance Iran's economic relationship with the West, particularly within the mining sector," and the scale of what has been inaccessible to Western capital for decades is considerable. Iran is ranked among the world's top 15 mineral-rich nations, possessing what Tehran's Chamber of Commerce values at an estimated $27.3 trillion in resource base. The country hosts 68 different types of minerals across approximately 6,000 active mines, with proven reserves placing it sixth globally in zinc, seventh in copper, and ninth in iron ore. A 2023 discovery of 8.5 million tonnes of lithium reserves in Hamadan province, based on hectorite clay, positioned the country as a potentially significant future player in the battery supply chain.
Yet the gap between geological endowment and productive capacity is wide. Iranian analyst Dalga Khatinoglu has noted that the mining sector accounts for just around 1 percent of Iranian GDP despite the country's vast reserves, a figure he describes as clearly reflecting its "underdevelopment." Mohammad Hassan Goodarzi, vice president of the Iran Chamber of Commerce, identified a persistent constraint: the lack of access to Western equipment following the reimposition of US sanctions during Trump's first presidency. Nandini Roy Choudhury of Future Market Insights framed the structural problem precisely: "The bottleneck is not resource availability, but conversion efficiency. Without access to modern technology, stable energy and global markets, the sector will remain operational but inefficient." The MOU, if it holds and progresses to a final agreement, changes those conditions materially.
The Venezuela Template: How Washington Has Done This Before
The framework for understanding how the United States might approach Iranian mineral sector access already exists. It was constructed, with less fanfare, over the preceding months in Venezuela.
On March 27, 2026, the Treasury Department's Office of Foreign Assets Control issued amended and new general licenses significantly expanding the scope of authorised activity in Venezuela's minerals sector. General License 51A replaced its predecessor to extend authorised trading activities from Venezuelan-origin gold specifically to Venezuelan-origin minerals generally, covering the exportation, sale, storage, purchase, and transportation of all Venezuelan minerals by established US entities. Interior Secretary Doug Burgum had visited Caracas to meet with Venezuelan officials and representatives from more than two dozen American mining and minerals companies. The message from Washington was explicit: by selectively authorising activity necessary to stabilise Venezuela's metals and mining sectors, the United States was preserving influence over a strategically significant supply while mitigating the risk that production capacity would shift toward American adversaries.
The Venezuelan licenses contain a restriction that, given the ceasefire, may now read as a relic of a different diplomatic moment. GL 51A clarifies that the processing or refining of Venezuelan-origin minerals is authorised outside of Venezuela, except in Russia, Iran, North Korea, Cuba, or China. Iran's inclusion on that exclusion list was, until last week, unremarkable. Its status in a post-ceasefire, post-sanctions-waiver environment is rather less clear, and the question of whether OFAC will update that language is one that trade lawyers at firms with Middle East practices are already asking.
The Venezuela parallel also points to an element of the Iran MOU that has received little attention in the critical minerals context. As part of the agreement, Iran is expected to regain access to frozen assets that could amount to tens of billions of dollars. Mohsen Rezaei, military adviser to Supreme Leader Mojtaba Khamenei, has publicly stated Iran wants to see the release of $24 billion. One of the assets that becomes relevant with sanctions relief is Iran's 15 percent stake in Namibia's Rössing Uranium Mine, acquired through a 1976 investment. With Western uranium supply chains under sustained pressure, that stake's re-entry into global markets is a detail that mine finance teams will be tracking closely.
Building on my analysis of the Venezuela minerals authorisations in the context of the broader US sanctions architecture, in "The New Expropriation" last month, there is a recognisable logic operating here. Washington is learning to use sanctions relief as an instrument of supply chain construction rather than purely of geopolitical pressure. The goal is not merely to punish adversaries but to redirect mineral flows toward American entities and allied processing networks, and to do so before Chinese capital fills the vacuum that sanctions have created.
A Sixty-Day Window and the Architecture of Uncertainty
The ceasefire agreement's most important single number, for the minerals industry, is sixty. The MOU starts a sixty-day negotiating clock to resolve remaining issues around Iran's nuclear programme, the scope of sanctions relief, and the financial architecture of reconstruction. The immediate oil sanctions waivers, which allow Iran to resume crude oil, petrochemical, and derivatives exports with associated banking and insurance services, are operationally significant for global energy markets. But the full suite of sanctions termination, including UN and IAEA sanctions as well as unilateral measures, is contingent on a final agreement that has not yet been negotiated.
For the minerals industry, this creates a layered set of conditions. The near-term relief on sulfur and sulfuric acid prices flows primarily from the Strait's reopening, which should occur regardless of whether the sixty-day nuclear negotiation succeeds. The longer-term opportunity to direct Western capital into Iranian copper, zinc, lithium, and uranium assets is contingent on a final deal and a detailed sanctions unwind that OFAC would have to architect with considerable care, particularly given the complexity of existing UN-level restrictions.
Mona Yacoubian of CSIS captured the scale of what the Strait's reopening alone represents: "Perhaps the most significant element of the deal is that it will result in the reopening of the Strait of Hormuz, after now nearly four months of being closed with enormous negative repercussions for energy markets and economies, really, around the world." That assessment is correct as far as it goes. But the Hormuz crisis has also functioned as a diagnostic, revealing structural vulnerabilities in critical mineral supply chains that sulfur price relief alone will not fix. The absence of a strategic sulfur reserve, the lack of any coordinated emergency release mechanism comparable to the IEA's oil protocols, and the extreme geographic concentration of processing reagent supply all predate the February conflict and will persist after the ceasefire is formalised.
As I reported in "Sixty Percent and Falling" last week, the G7 summit in Evian produced a commitment to reduce dependence on any single non-G7 supplier of rare earths and permanent magnets to below 60 percent by 2030. The Hormuz crisis has demonstrated that the supply chain resilience problem extends well beyond the rare earth refining capacity that the 60 percent target addresses. A country that controls none of the rare earth mine output and none of the refining capacity can still bring critical mineral processing to a halt simply by controlling a maritime chokepoint through which the processing chemistry travels. That lesson, more than the specific terms of any MOU, is the one that minerals policy architects will be working through long after the Versailles dinner is forgotten.
Conclusion: The Price of an Open Strait
On the morning of June 22, five days after the Versailles signing, a sulfur cargo that had been anchored near Fujairah waiting for passage clearance was reported to have successfully transited the strait. It was, according to those tracking vessel movements, the first confirmed commercial sulfur shipment to complete the crossing since February. The news travelled quickly through the community of mineral processors who had spent four months watching prices double and output fall.
The broader picture remains complicated. Iran closed the strait again two days earlier before reopening it, demonstrating the fragility of any arrangement that depends on the sustained goodwill of a government still engaged in a nuclear negotiation with sixty days on the clock. The $300 billion reconstruction fund, whose financing Vice President Vance has attributed to Gulf Arab nations rather than the US Treasury, remains an aspiration rather than a commitment. Former Secretary of State Antony Blinken's pointed observation that the ceasefire's primary achievement was the likely reopening of a strait that was open before the war began is not entirely unfair, however politically charged the framing.
But for the Indonesian nickel processor who has been rationing acid since April, for the Chilean copper miner who has been managing a processing backlog, and for the Lynas metallurgist in Kalgoorlie who has been explaining production misses to investors, the practical significance of an open strait is not abstract. The sulfur starts moving again, the acid price begins to fall, and the 60-day window that began at a dinner table in Versailles becomes the most closely watched negotiating clock in the critical minerals world. What it produces, and whether Western capital will ultimately find its way into Iran's underdeveloped mines, will determine whether the deal is remembered as the moment the minerals supply chain found a new frontier, or simply as the night a president signed a complicated piece of paper over dessert.