Copper smelting operations produce sulphuric acid as a byproduct essential for regional mining.
Two of Zambia’s largest copper smelters — and key producers of sulphuric acid — are set for extended maintenance shutdowns later this year, according to industry sources. The outages are expected to further constrain copper output and reduce supplies of sulphuric acid, a critical chemical used in processing copper and cobalt.
Global sulphuric acid supplies have already been disrupted by geopolitical tensions, including the Iran war, affecting availability of key leaching chemicals. Mines in neighbouring Democratic Republic of Congo (DRC) — the world’s largest cobalt producer and second-largest copper producer — have responded by cutting chemical usage or weighing potential output reductions.
Zambia, Africa’s second-largest copper producer, generates about 2 million metric tons of sulphuric acid annually, primarily as a byproduct of copper smelting, according to the country’s mines ministry. Most of the acid is consumed domestically, with surplus volumes typically exported to the DRC.However, sulphuric acid stocks in Zambia are now so depleted that there is effectively no export capacity, Anthony Mukutuma, Zambia country director for Canada-based First Quantum Minerals, told Reuters. The mines ministry did not immediately respond to requests for comment
Mopani and Chambishi Face Prolonged Maintenance
While copper smelters typically undergo annual maintenance lasting around 30 days, this year’s shutdowns at Mopani Copper Mines and Chambishi — 85% owned by China Nonferrous Metal Mining Group — are expected to be significantly longer.
According to a chemicals trading source, Mopani will close for three days in June, followed by a more extensive shutdown lasting 40 to 45 days between August and mid-September. A mining executive indicated that Mopani’s maintenance has been overdue, contributing to the need for a longer outage.
Chambishi is also scheduled to shut down for roughly two months through August, though specific reasons for the extended outage were not disclosed.
Officials from Mopani and Chambishi did not respond to requests for comment. Sources cited in the report requested anonymity because they were not authorized to speak publicly.
Export Controls Tightened
Sulphuric acid is vital for copper and cobalt leaching operations
Earlier this month, Zambia introduced tighter controls on sulphuric acid exports, requiring traders to obtain permits. The government said the measures are intended to safeguard domestic industry.
Mukutuma of First Quantum described the controls as fair but noted that exports are unlikely in the near term due to depleted domestic inventories.
Global Copper Supply Under Pressure
Years of underinvestment have constrained copper mine output growth globally
The smelter shutdowns come at a time when global copper supply is already expected to tighten, following years of underinvestment that have limited mine output growth.
Zambia produced 890,346 metric tons of copper last year, falling short of its 1 million-ton target. Meanwhile, shipping data reviewed by Reuters showed that Congo’s copper exports declined in the first quarter of this year.
Mopani is currently operating well below its 225,000 metric ton finished copper capacity, after years of underinvestment left it short of copper concentrate, according to a mining executive. The company’s majority owner, UAE-based International Resources Holding, is pursuing simultaneous development and mining activities, resulting in intermittent stoppages.
With extended smelter shutdowns and constrained chemical supplies, both Zambia and the broader central African copper belt face mounting pressure in an already tightening global market.