China Sulfuric Acid Export Suspension 2026: What Buyers Must Know begins with the recognition that bulk sulfuric acid is a tonnage industrial intermediate, not a fungible finished chemical across all applications. The suspension affects shipments declared under HS 2807.00 for technical-grade 98% acid, 93% acid, and oleum because a cargo acceptable for phosphate rock digestion may be outside specification for alkylation or battery duty due to iron, organic carbon, chloride, or residue carry-over. Under the 2026 licensing framework, the exporter is required to provide the export licence number, the loading port inspection certificate, and the UN transport classification on the bill of lading. Buyers that do not verify these documents before vessel nomination face berth refusal at discharge terminals where dangerous goods class 8 permits are tied to the importer’s shore-side storage certificate. Contract execution must therefore include a pre-loading survey by a third-party inspection company, a CIQ export inspection certificate, and a materials-compatibility check against the receiving installation’s tank lining, pump metallurgy, and vapour-return system.

Which Sulfuric Acid Grades Fall Inside the 2026 Export Suspension?

The suspension covers concentrated technical acid and oleum sold under Chinese national standard GB/T 534-2014, and battery-grade material conforming to HG/T 2692-2015. A standard 98% technical acid cargo is specified by a minimum H₂SO₄ content of 98.0%, a maximum ignition residue of 0.05%, and a maximum iron content of 0.010%. For 93% acid, the minimum H₂SO₄ content is 93.0%, and the same residue and iron ceilings commonly apply. Oleum grades are specified primarily by free SO₃ content: 20% oleum contains 20.0% free SO₃, and 65% oleum contains 65.0% free SO₃. The table below summarises the main contractual grades and test designations used in pre-shipment inspection.

Compliance verification for spot cargoes under the suspension begins with sampling at the loading port following ISO 3165:1976 and analysis under ISO 910:1977 or ASTM E223-23. The titration methods determine total acidity, and the result is converted to H₂SO₄ or free SO₃ depending on the grade. For oleum cargoes, the free SO₃ value is not a minor specification; it determines the actual equivalent H₂SO₄ mass available for sulfonation or dehydration. A 20% oleum parcel that has absorbed atmospheric moisture during loading may fall below the declared free SO₃ content, shifting the heat balance of the receiving plant. Buyers that do not require loading-port titration against ISO 910:1977 face later shipper disputes because the analytical certificate is the basis for price adjustment and demurrage claims. Independent surveyors should also measure density at 15°C or 20°C as a cross-check against the bill of lading, with correction tables referenced to the measured temperature.

Storage metallurgy when port dwell times exceed normal unloading windows

A 98% acid storage tank is not merely a hold point; it is an active corrosion control system. Carbon steel in concentrated sulfuric acid develops a protective iron sulfate film, provided that the acid concentration remains above approximately 93% and that flow velocity is kept below the threshold that erodes the film. Design guidance in NACE SP0294-2006 for concentrated sulfuric acid and oleum storage at ambient temperatures specifies carbon steel plate, bottom-to-shell weld details that avoid crevices, and internal piping placement designed to prevent acid jet impingement on the shell. When port dwell times increase because of export suspension delays, tanks previously operated at 85% capacity may be held at higher levels for longer periods, and the vapour space becomes the most vulnerable zone. Moisture ingress through atmospheric vents dilutes surface acid, producing local corrosion rates far above the acceptable range. Receiving terminals should therefore use dry-air or inert-gas blanketing with a dew point below -40°C and should maintain vent-line tracing where climatic condensation is possible. For unloading pumps, PTFE-lined or Alloy 20 centrifugal pumps are used where turbulent flow exceeds the velocity limits acceptable for bare carbon steel; published data for this specific configuration is limited and should be confirmed by a materials engineer before a cargo is diverted to an unfamiliar terminal.

Phosphate rock acidulation is the single largest consuming route for technical-grade sulfuric acid, and the 2026 export suspension affects this chain directly because substitution from another acid supplier changes reactor stoichiometry only if the replacement acid has a different concentration or impurity profile. In the dihydrate wet-process, ground fluorapatite is attacked with 93–98% sulfuric acid in a reactor train operating at 70–80°C, with slurry P₂O₅ held at 26–30%. The free sulfate in the reactor is maintained at 20–35 g/L as SO₃ to stabilise gypsum crystal growth and to prevent hemihydrate scaling on the filter cloth. If a buyer is forced to replace 98% Chinese acid with 93% acid from another source, the water addition to the reactor increases, and the operator must reduce filter wash water or raise evaporative capacity in the flash cooler. The critical threshold is not assay alone but the combined sulfate-to-calcium ratio in the feed: local deficiencies produce orthorhombic hemihydrate needles that blind the filter, while excess sulfate produces crusted gypsum that reduces filtration rate. Continuous vacuum filtration on tilting-pan or belt filters requires a crystal slurry that dewaters at a rate compatible with the plant’s P₂O₅ production target; a 10% loss in filtration rate can force a downrate of the entire granulation train.

When oleum substitution changes sulfonation plant heat balances

Oleum is transported under UN 1831 and is used where a strong sulfonating or dehydrating agent is required: linear alkylbenzene sulfonation, dye intermediate production, and methyl ester sulfonation. A sulfonation plant designed for 20% oleum cannot simply switch to 65% oleum without recalculating jacket cooling loads and vent-line capacity because the hydration of free SO₃ is highly exothermic. The heat evolution from free SO₃ absorption is sufficient to vapourise residual water and to form acid mist if local mixing is not immediate. Reactor temperature in detergent sulfonation is controlled below 60°C where product colour and sulfone formation become sensitive to hot spots; a 65% oleum feed raises the local heat release at the point of injection relative to 20% oleum. Static mixers or film sulfonators must be specified for the higher free SO₃ grade, and the exhaust gas system must handle higher SO₃ vapour pressure. Unloading infrastructure for oleum also requires heated trace piping where the ambient temperature is below the freezing point of the specific grade; 20% oleum has a lower freezing point than 65% oleum, so terminal operators must confirm that the steam tracing and insulation are rated for the grade actually supplied.

Battery-grade sulfuric acid is not defined by a single concentration but by impurity ceilings after dilution to 1.280 kg/L electrolyte at 25°C. The concentrated precursor is typically 98% acid with lead, arsenic, chloride, organic carbon, and nitrogen compounds controlled to levels compatible with lead-acid cell service. Verification against HG/T 2692-2015 and IEC 60095-1:2018 is used where the electrolyte is destined for automotive or stationary batteries. The most serious contamination in this duty is chloride, because chloride migrates to the positive electrode and initiates grid corrosion; arsenic and antimony alter hydrogen evolution and can shift float-current demand. A parcel of standard technical acid from a non-battery source may meet 98% concentration but fail battery-grade impurity limits, so the 2026 suspension forces battery producers to require an additional certificate of analysis for trace elements not included in typical technical-grade trade. The certificate should state the test method for each trace element, the detection limit, and the exact sample point, because post-loading contamination from a shared transfer line can invalidate a shore-side sample.

Sulphate-process titanium dioxide feedstock acid quality controls

Sulfate-process titanium dioxide production uses concentrated sulfuric acid to digest ilmenite at 150–180°C, forming titanyl sulfate and iron sulfate. The digestion reactor is acid-resistant brick-lined or constructed with an acid-proof steel shell, and the acid-to-ilmenite ratio is controlled by the total titanium and iron content of the ore. A change in acid concentration from 98% to 93% increases the water load in the digestion step and changes the subsequent hydrolysis behaviour of the titanyl sulfate solution. Iron content in the acid is additive to the iron load from ilmenite, and chloride content above the technical-grade ceiling can promote pitting in the downstream evaporation train. Hydrolysis is conducted at 95–100°C with seeding to control particle size distribution; the seed slurry temperature and the acid-to-titania ratio are the primary variables that determine rutile or anatase crystal form after calcination. A buyer replacing Chinese 98% acid with an alternative 98% supply should still compare the certificate of analysis for chloride and oxidising impurities because the export suspension does not suspend the need for process stability. Filtration of the hydrolysis pulp through rotary vacuum filters is sensitive to the residual iron oxidation state; if ferric iron content is not controlled by scrap iron addition, the filter cloth blinds with colloidal iron hydroxide.

Ocean transport of concentrated sulfuric acid under the 2026 suspension requires compliance with the IMDG Code class 8 packing group II for UN 1830, and with UN 2796 for sulfuric acid not exceeding 51% acid. The compliance matrix below summarises the core transport and shore-side documentation that must be checked before a cargo is accepted.

High-pressure acid leaching of nickel laterite represents the most severe duty for purchased acid. Autoclaves operating at 245–270°C and 4.0–5.0 MPa require a steady acid feed with minimal chloride because chloride-induced pitting of titanium-lined autoclaves becomes a critical maintenance variable. The suspension of Chinese acid exports in 2026 forces nickel producers to revalidate their feed specification against the replacement acid source, with particular attention to silica, chloride, and suspended solids. Silica in acid can combine with leached iron and aluminium to form scale on the autoclave walls, reducing heat-transfer capacity and increasing scheduled descaling frequency. Feed acid is injected through high-pressure quench lines designed for the acid temperature and flash-steam environment; blockages at the quench nozzle result in uneven temperature distribution and reduced nickel extraction. Published data for the combined effect of the 2026 suspension on HPAL autoclave feed quality is limited at the time of writing, so each site must qualify its replacement acid through continuous pilot-scale autoclave testing rather than relying on the standard technical-grade certificate alone.