Published on: 2026-05-12
The energy transition’s overlooked bottleneck is not only a metal. It is the acid needed to process one. The Sulfur Pincer is tightening because copper leaching, phosphate fertilizer and crop nutrition all depend on sulfuric acid, while much of the sulfur supply chain still comes from petroleum refining, natural gas processing and smelting byproducts.
In 2026, reported restrictions on Chinese sulfuric acid exports, Gulf-linked sulfur disruption and elevated fertilizer input costs turned that contradiction into a live market problem. (1)(2)(3)
The market is mispricing sulfur as a commodity input when it increasingly behaves like a systems constraint. A sulfur balance can look comfortable globally while failing locally at a copper mine, fertilizer plant or food-importing economy. World sulfur production was estimated at 84 million tonnes in 2025, barely above 83.9 million tonnes in 2024, while new demand was expected from phosphate fertilizer projects and high-pressure acid leach projects for battery materials. (4)
The sulfur squeeze has shifted from structural risk to current market pressure, as restrictions on Chinese sulfuric acid exports, Gulf-linked disruptions, and rising sulfur input costs affect metals, fertiliser, and phosphate supply chains. (1)(2)(3)
Sulfur supply is less flexible than headline resource estimates imply because recovered sulfur comes mainly from petroleum refineries, natural gas processing plants and coking plants, while byproduct sulfuric acid comes from nonferrous-metal smelters. (4)
Copper leaching converts electrification demand into sulfuric acid demand, especially in Chile, where China supplied 37.1% of sulfuric acid imports in 2025, leaving the copper sector exposed to shifts in export availability. (2)
Fertilizer markets connect sulfur to food security through phosphoric acid, DAP, MAP and TSP. Liquid sulfur prices nearly tripled from the end of 2024, while DAP prices were projected to rise 26% in 2025 before easing. (3)
Cleaner fuels have reduced an unintended sulfur input to farmland. Atmospheric sulfur deposition to agricultural soils is projected to decline by 70% to 90% across much of the Northern Hemisphere under cleaner energy scenarios. (5)
The sulfur story has shifted from balance-sheet risk to physical-market stress. Lower availability of Chinese sulfuric acid exports has tightened supply for import-dependent buyers, while Gulf disruptions have raised concerns about sulfur flows used to produce acid. Chile and Indonesia face supply pressure, with copper and nickel output exposed if alternative supply cannot be secured. (1)(2)
The stress is also visible in fertilizer. Fertilizer prices eased in late 2025 but remained constrained by rising input costs, export restrictions and shifting trade flows. Liquid sulfur prices nearly tripled from the end of 2024, keeping phosphate fertilizer exposed even as some benchmark prices softened. (3)
The transmission is direct. Copper mines need acid to leach ore. Phosphate fertilizer producers need sulfuric acid to make phosphoric acid. Food-importing countries need affordable fertilizer to protect yields. When sulfur and sulfuric acid tighten together, the pressure moves across mining costs, fertilizer margins and food-security budgets.
The common mistake is to treat sulfur as a low-value byproduct with limited strategic relevance. That view misses the transmission mechanism. Sulfur does not need to become globally scarce to influence markets. It only needs to become unavailable in the right chemical form, at the right port, for the right buyer.
Copper analysis usually focuses on ore grade, power, water, permitting and capex. Fertilizer analysis usually focuses on ammonia, phosphate rock, potash, gas prices and subsidies. Food-security analysis often centers on crop yields, grain trade and currency pressure. Sulfur sits between these models. It enters copper through leaching, fertilizer through phosphoric acid and food systems through crop nutrient replacement.
That gap creates the pincer. A reduction in the availability of Chinese sulfuric acid exports is not only a trade-flow story. A Red Sea or Gulf disruption is not only a freight story. A liquid sulfur price spike is not only a fertilizer input story. Each can transmit into copper operating costs, phosphate fertilizer margins and sovereign fertilizer bills through the same chemical system.
Sulfur’s strategic risk begins with its supply chain. The market does not behave like copper, lithium or nickel, where higher prices can pull forward primary mine supply. Recovered sulfur is produced mainly because another industry is processing oil, gas, coke or sulfide ores.
In the United States, about 90% of sulfur consumed in 2025 was in the form of sulfuric acid, and 34% of domestic sulfur consumption came from imported sulfur and sulfuric acid. Most production remains tied to fossil-fuel processing, and sulfur may be recovered far from the country where the original hydrocarbon resource was extracted. (4)
Copper demand is typically discussed in terms of electrical grids, electric vehicles, renewable energy, and mine permitting. The chemical input chain receives less attention. In leaching-heavy copper systems, sulfuric acid is a core production input rather than a peripheral expense.
Chile is the clearest case. The country produced 23.8% of global mined copper in 2024, and analysts estimate that about one-fifth of the world’s copper is extracted using sulfuric acid-based methods. China accounted for 37.1% of Chile’s sulfuric acid imports under HS 2807 in 2025, leaving Chile exposed to any reduction in Chinese export availability. (2)
The copper market may be underestimating the risk posed by chemical inputs. Ore grade, power access, water supply and permitting remain central to copper forecasts. Sulfuric acid availability should sit on the same dashboard for oxide-heavy and solvent extraction-electrowinning operations.
Fertilizer production transforms sulfur from an industrial input into a food-security variable. Sulfuric acid processes phosphate rock into phosphoric acid, which then feeds DAP, MAP and TSP production. Constraints in sulfur or sulfuric acid supply can affect phosphate fertilizer availability before the pressure appears in crop prices.
The fertilizer market entered 2026 with affordability still strained. Prices moderated in late 2025 but remained about 17% higher than a year earlier. Affordability indexes stayed elevated compared with the pre-2022 period, and the DAP affordability index remained above its early-2022 peak. (3)
India, Bangladesh and selected Sub-Saharan food-deficit economies are particularly vulnerable.
India combines high fertilizer demand, sulfur-linked input exposure and widespread sulfur-deficient soils.
Bangladesh is sensitive to fertilizer affordability because of import dependence and subsidy burdens.
Sub-Saharan food-deficit economies face limited fertilizer-use buffers and ongoing nutrient depletion.
Improvements in air quality have altered the sulfur balance in agriculture. For decades, sulfur from fossil-fuel combustion and industrial emissions was deposited onto soils. Pollution controls reduced acid rain and improved air quality, but they also lowered atmospheric sulfur inputs to agricultural land.
Research in Communications Earth & Environment projects sulfur deposition declines of 70% to 90% across agricultural soils in Asia, North America and Europe by the end of the century under cleaner-energy scenarios. (5)
The agronomic impact is a transition from incidental sulfur supply to intentional sulfur management. Nearly 70% of Indian soil samples analysed through ICAR-linked and industry programmes were found to be either deficient or marginal in plant-available sulfur. (7)
Most sulfur analysis treats industrial demand, fertilizer production, crop nutrition and shipping risk as separate factors. The Sulfur Pincer Exposure Index integrates these elements into a single country-level stress screen.
A country scores higher when sulfur stress can transmit through multiple channels at once. The index does not rank countries by sulfur consumption. It ranks where sulfur disruption can translate most directly into economic pressure. Each channel is scored from 0 to 5 and weighted into a 0 to 100 composite score: import and acid exposure at 25%, fertilizer exposure at 25%, copper acid demand at 20%, shipping chokepoint risk at 15% and soil sulfur deficiency risk at 15%.
| Rank | Country/Region | Import/Acid Exposure | Fertilizer Exposure | Copper Acid Demand | Shipping Risk | Soil Risk | Index Score | Exposure Band | Data Confidence |
|---|---|---|---|---|---|---|---|---|---|
| 1 | India | 4/5 | 5/5 | 1/5 | 4/5 | 5/5 | 76 | Very High | High |
| 2 | Bangladesh | 5/5 | 5/5 | 0/5 | 4/5 | 3/5 | 71 | Very High | Medium |
| 3 | Chile | 5/5 | 1/5 | 5/5 | 4/5 | 2/5 | 68 | High | High |
| 4 | Morocco | 5/5 | 5/5 | 0/5 | 4/5 | 1/5 | 65 | High | Medium-High |
| 5 | Sub-Saharan food-deficit basket | 4/5 | 5/5 | 1/5 | 3/5 | 5/5 | 63 | High | Medium-Low |
| 6 | Peru | 2/5 | 2/5 | 4/5 | 2/5 | 2/5 | 48 | Moderate | Medium |
Methodology note: The index is a relative exposure screen, not a price forecast. A score of 0 indicates minimal exposure, and 5 indicates high exposure. Scores are based on sulfur and sulfuric acid import reliance, fertilizer import dependence, phosphate fertilizer exposure, copper leaching intensity, shipping-route vulnerability and available evidence of soil sulfur deficiency.
The Sub-Saharan food-deficit basket refers to selected fertilizer-import-dependent economies with documented nutrient depletion, limited affordability buffers and high crop-yield sensitivity to nutrient stress. The basket captures a regional channel of exposure to food security. It does not treat Sub-Saharan Africa as a single commodity market.
India ranks in the highest exposure band because sulfur risk reaches the economy through fertilizer demand, import routes and soil sulfur depletion.
Bangladesh also ranks in the highest band because USDA describes the country as heavily dependent on imports of urea, TSP, DAP and MOP, with limited domestic production and a significant subsidy burden. (7)(8)
Chile ranks highest in copper-related sulfur risk. Its total score is lower than India's and Bangladesh's because exposure is narrower, but the copper channel is more acute.
Morocco ranks highly because sulfur is essential for phosphate conversion.
Sub-Saharan food-deficit economies rank highly in terms of agronomic and affordability exposure rather than industrial acid demand.
FAO’s cropland nutrient-balance work shows Africa has low nitrogen surplus and phosphorus and potassium deficits per hectare of cropland, reinforcing the low-buffer food-system risk. (2)
Sensitivity check: Chile rises under a copper-heavy weighting. Morocco rises under a phosphate-conversion weighting. India and Bangladesh remain in the highest exposure group under a food-security weighting. The stable finding is that sulfur risk is not one market. It is a transmission channel across mining, fertilizer and food systems.
Sulfur risk manifests regionally before becoming a global issue. A market may appear balanced in aggregate, yet delivered sulfuric acid can become scarce at a mine, port or fertilizer plant.
UNCTAD’s 2025 maritime review describes a shipping environment defined by uncertainty, volatility and rising costs, with freight-rate volatility and weaker supply-chain reliability. For sulfur and sulfuric acid, logistics are embedded in the commodity. Acid is hazardous, heavy and harder to redirect than many bulk cargoes. Disruptions in the Suez Canal, the Red Sea, the Strait of Hormuz, or the Panama Canal can alter landed costs before benchmark prices respond. (6)
If sulfuric acid supply remains tight in the Pacific basin, copper producers with leaching exposure face a broader input-risk premium through 2026 and beyond. The first pressure point is not necessarily mine closure. It is ore sequencing, acid procurement, working capital and marginal cathode output.
If sulfur-linked input costs stay elevated, phosphate fertilizer producers face tighter conversion economics. The pressure can move through phosphoric acid into DAP, MAP and TSP, even when headline fertilizer benchmarks soften. Import-dependent food systems then absorb the shock through higher subsidy costs, weaker affordability or lower application rates.
If shipping disruption persists across the Red Sea, Suez, Panama or Gulf-linked routes, sulfur stress becomes a delivered-cost problem rather than a benchmark-price problem. Countries that import fertilizer, rely on seaborne sulfur supply or depend on copper export revenues face different versions of the same exposure.
Sulfur is transitioning from background chemistry to strategic exposure. Its supply chain was established around byproducts from fossil-fuel processing, refining and smelting, while demand is increasingly driven by copper leaching, phosphate fertilizer production and soil nutrient replacement.
The next signal may not come solely from sulfur prices. It may appear first in copper operating costs, phosphate fertilizer margins, shipping premiums or sovereign fertilizer subsidies.
Final Takeaway: Sulfur is not becoming scarce. It is becoming mispriced as a regional, logistical and systems risk.
(1) https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-sulfur.pdf
(4) https://www.nature.com/articles/s43247-021-00172-0
(5) https://unctad.org/publication/review-maritime-transport-2025
(6) https://www.sulphurinstitute.org/about-sulphur/india/status-of-indian-soils/
(7) https://www.fas.usda.gov/data/gain/2026/03/bangladesh-fertilizer-situation-bangladesh
