While attention is focused on the closure of the Strait of Hormuz and its impact on oil markets, another, less visible crisis is unfolding behind the scenes: sulfuric acid, a chemical compound essential to part of global copper production.

Among the many figures Ivanhoe Mines released Monday in its first-quarter 2026 results, those related to its copper smelter in the Democratic Republic of Congo stood out. Alongside anode production, the facility at the Kamoa-Kakula copper mine produced 117,871 metric tons of sulfuric acid during the period, a byproduct of smelting sulfide concentrates.

The volume comes at a critical time for Congolese copper producers, who are bracing for a global sulfuric acid shortage partly driven by the war in Iran.

No acid, no copper

To understand what is at stake, it is essential to grasp the central role sulfuric acid plays in copper extraction. About 20% of global production of the red metal relies on a hydrometallurgical process known as leaching, in which acid is applied to oxidized ores to extract copper. Without acid, there is no copper, at least from this category of deposits, which accounts for a significant share of Congolese output.

The war in Iran and the near-closure of the Strait of Hormuz to sulfur traffic, the raw material from which sulfuric acid is made, has cut off nearly half of shipments from the Middle East to world markets. According to S&P Global, Africa depended on the region for about 48% of its sulfur imports in 2025. The situation benefits Ivanhoe Mines, as its mining operations do not require sulfuric acid, and the company does not have to look far to find buyers for what it produces.

"Our on-site copper smelter produces high-strength sulphuric acid as a by-product, which we sell to oxide copper mining operations in the DRC Copperbelt," said Robert Friedland, founder and co-chairman of the Canadian company. Chief Executive Officer Marna Cloete told Reuters that Swiss miner Glencore and Kazakhstan's Eurasian Resources Group are already among its customers.

An insufficient cushion given the scale of needs

The Kamoa-Kakula smelter, which only came online at the end of December 2025, has an annual copper production capacity of 500,000 metric tons, making it the largest in Africa. At full capacity, its sulfuric acid output is expected to be higher, between 600,000 and 700,000 metric tons. Significant as those volumes are, they would not fill the emerging shortfall. The Congolese sulfuric acid market alone represents approximately 2 million metric tons per year, according to Cloete's estimates.

Even running at full capacity, the Kamoa-Kakula smelter would cover only one third of that demand, leaving a shortfall that imports will need to fill. Signs of strain are emerging on international markets. Several copper producers in the DRC have reportedly had orders for essential chemicals canceled or withdrawn by suppliers in recent weeks.

Further pressure could come from Beijing

According to Bloomberg, China is preparing to suspend sulfuric acid exports starting in May to protect its own agricultural needs during the planting season. Sulfuric acid is also used in fertilizer production. The restriction, which could extend through all of 2026, would tighten an already strained market. In South America, acid prices rose 44% in a single month in Chile, the world's largest copper producer, just ahead of the DRC.

In the central African country, miners are now reportedly reducing their chemical consumption to stretch existing stockpiles, a move that is likely to affect copper output volumes. While Friedland said there will be repercussions for global copper production, the full extent of the impact on output forecasts at several Congolese mines remains unclear.

Emiliano Tossou