When most people think about what it takes to produce copper, the metal in our wiring, our EVs, our data centers, and the entire electrification push the world is banking on they picture drills, blasting, and giant open-pit mines. Few think about sulphuric acid. Yet this unglamorous industrial chemical is, for a fifth of the world's copper supply, just as essential as the ore itself. And right now, a geopolitical crisis unfolding thousands of miles from any copper mine is threatening to choke off the acid that keeps that production running.

Copper doesn't come out of the ground as shiny wire-ready metal. It comes in two broad ore families, and each demands a completely different extraction chemistry.

Sulphide ores, the deeper, harder rock that makes up the majority of the world's copper reserves, are processed through smelting. The ore is crushed, concentrated, and then roasted at extreme temperatures to separate copper from the sulphur and iron it's chemically bound to. This is where things get interesting: smelting sulphide ore actually produces sulphuric acid as a by-product, because the sulphur released during roasting is captured and converted into acid rather than vented as pollution. Large integrated smelters can become net sellers of acid rather than buyers.

Oxide ores are a different story. These sit closer to the surface, are typically lower-grade, and cannot be smelted economically. Instead, producers use a process called heap leaching (or in some cases in-situ leaching): crushed ore is stacked into massive heaps, and dilute sulphuric acid is sprayed over the top. As the acid trickles down through the pile, it dissolves the copper minerals into a copper sulphate solution, which is collected at the base. From there, the "pregnant leach solution" moves through solvent extraction and electrowinning (the SX-EW process) to produce cathode copper, the 99.99% pure copper that actually gets traded and used industrially.

Roughly one in five tons of copper produced worldwide depends on this acid-leaching pathway. For countries like Chile and Peru, where oxide and mixed ores make up a substantial share of national output, sulphuric acid isn't a minor input line on a spreadsheet, it's a rate-limiting reagent. No acid, no leaching. No leaching, no copper cathode. It's that direct.

What makes sulphuric acid such an unusual commodity is that almost nobody produces it because they want sulphuric acid. It's overwhelmingly a by-product of smelting copper, zinc, and other metals, and of refining sour crude oil and natural gas, which contain sulphur that must be stripped out before the fuel can be sold. That sulphur is burned to make sulphuric acid, largely because it's easier and more profitable to sell it than to dispose of it.

This means the global acid market is fundamentally a by-product market layered on top of two completely unrelated industries: metallurgy and petroleum refining. When something disrupts oil and gas operations in a major sulphur-producing region, the knock-on effect on copper mining on the other side of the planet can be severe, even though oil and copper have nothing to do with each other on the surface.

That's precisely the mechanism now playing out with the Strait of Hormuz.

The Strait of Hormuz is best known as the world's most important oil chokepoint, historically carrying around a quarter of global seaborne oil trade and roughly a fifth of global LNG. What is far less appreciated is that the Gulf region through sour gas processing in the UAE, Qatar, and Saudi Arabia. It is also one of the largest sources of elemental sulphur and sulphuric acid feeding world markets, normally accounting for a substantial share of global seaborne sulphur exports.

Since the escalation of the Iran war beginning in late February 2026, that route has become a warzone. Iran's Revolutionary Guard Corps has laid mines, boarded and struck merchant vessels, and repeatedly declared the strait closed, while the United States has run a parallel military campaign and a naval blockade of Iran aimed at keeping the passage open. The result has been a chaotic back-and-forth: some days a trickle of traffic moves along a southern route hugging the Omani coast; other days shipping "grinds to a halt" entirely amid renewed strikes and confirmed mines in the waterway. As of mid-July 2026, commercial transits remain a small fraction of pre-crisis levels, even as the US and Iran publicly dispute whether the strait is "open" or "closed."

For sulphur markets, the practical effect has been described starkly by industry figures: with roughly half of global seaborne sulphur supply effectively cut off, sulphur and sulphuric acid markets have become extremely tight. Cargoes that would normally have loaded and sailed have instead queued up in the Middle East Gulf with nowhere to go, while buyers downstream, specifically mining companies in Chile, Peru, and elsewhere, have scrambled for alternative sources.

If the Hormuz disruption were the only shock, the market might have absorbed it through alternative suppliers and drawn-down inventories. Instead, it has collided with a second, unrelated supply shock. China, the world's second-largest sulphuric acid exporter and a critical supplier to Chile in particular, moved from a 700,000-tonne annual export quota to a complete export ban on sulphuric acid effective through August 2026, announced in stages between April and May. China had typically exported around 2.7 million tons of sulphuric acid a year, with Chilean copper operations as one of its principal destinations.

The combination is what analysts have called a "triple shock": the Hormuz closure, China's export ban, and a Russian sulphur export ban layered on top of a structural supply deficit that already existed in Asian sulphur markets. Alternative producers — Kazakhstan, Qatar (via routes outside the strait where possible), and others — have not been able to fully offset the shortfall, partly because a meaningful share of their spare capacity is already tied up in long-term contracts with buyers in India and Morocco, chiefly for fertilizer production.

The market impact has been immediate and visible. Spot sulphuric acid prices, which traded at more ordinary levels before the crisis, pushed past $500 a ton in the early stages of the disruption and have remained elevated as the conflict has dragged on through the northern summer. Copper prices themselves have responded: COMEX copper futures surged toward historic highs in May 2026, with analysts explicitly linking the rally to sulphur-driven acid scarcity rather than to the more traditional demand-side stories that usually move copper.

Not every copper producer is equally exposed. Integrated smelter-refiner operations, especially those that produce their own sulphuric acid as a smelting by-product have found themselves in an unusually strong position. Ivanhoe Mines' Kamoa-Kakula complex in the Democratic Republic of Congo, home to Africa's largest copper smelter, produced well over 100,000 tons of high-strength sulphuric acid in the first quarter of 2026 alone, comfortably exceeding its own operational needs and allowing it to sell surplus acid to other copper operations across the Congolese Copperbelt. That kind of self-sufficiency has become a genuine competitive advantage almost overnight, turning what used to be a secondary by-product stream into a strategic asset.

Even so, no operation is fully insulated from a crisis of this scale. Ivanhoe itself has trimmed its 2026 copper anode production guidance and taken contingency measures including forward-purchasing diesel to keep operations running through a broader logistics environment strained by the wider war.

Pure leach operations dependent on imported acid are in the more precarious position, particularly in Chile, which is both the world's largest copper producer and historically one of the largest importers of Chinese sulphuric acid. With that channel closed and Middle Eastern supply severely constrained, Chilean and Peruvian SX-EW producers are the segment of the industry most exposed to the acid crunch, facing rising input costs and, in prolonged scenarios, genuine production constraints rather than just margin pressure.

Analysts tracking the situation have generally framed the risk in terms of duration rather than severity alone. Under roughly six weeks of disruption, alternative sulphur sourcing and existing inventories can bridge the gap, and the effect shows up mainly as price volatility rather than actual production losses. Stretch the closure to somewhere between six and twelve weeks, and leaching operations begin to face genuine acid supply constraints, with downstream manufacturing pipelines starting to register real shortfalls and copper prices facing sustained upward pressure rather than a temporary spike.

Given that the Hormuz crisis began on February 28, 2026, and remains active with mines confirmed in the strait, both sides disputing whether it is even open, and daily transit counts still running at a small fraction of normal the industry is now well past the point where this can be treated as a short-term blip. It has moved into the territory where structural effects on copper supply become plausible rather than theoretical.

The situation is a useful reminder that modern commodity markets rarely move on a single variable. Copper prices have traditionally been read as a barometer for global industrial activity, the so-called "Dr. Copper" effect. What the events of 2026 have illustrated is that copper pricing now also has to account for geopolitical risk in entirely unrelated sectors, chemical input scarcity, energy market disruption, and the compounding effect of policy decisions made in Beijing as much as events in the Persian Gulf.

For an industry central to the energy transition electric vehicles, grid infrastructure, renewable generation all depend heavily on copper the fact that its supply chain runs, in part, through a contested 33-kilometre-wide waterway between Iran and Oman is a sobering illustration of how interconnected and fragile these systems have become. Sulphuric acid may never get the headlines that oil does, but as 2026 has shown, it deserves far more attention than it usually receives.