Phosphoric acid from China

Zero duty, reported as P2O5

Read from the UK Trade Tariff on 26 September 2026, diphosphorus pentaoxide (2809 10 00 00) and phosphoric acid and polyphosphoric acids (2809 20 00 00) carried 0% duty on goods from China, with no anti-dumping measure. The supplementary unit for phosphoric acid is kilograms of P2O5, so an 85% acid, which contains about 61.6% P2O5 by weight, is declared by its P2O5 content as well as its gross weight.

Phosphate salts such as sodium tripolyphosphate are covered in our phosphates guide, and fertilisers made from the acid in our NPK, DAP and MAP guide.

Grades and handling

Technical grade is used in metal treatment, cleaning products and fertilisers; food grade is additive E 338 in soft drinks and processed foods, and must meet the purity criteria on the [FSA food additive authorisations register](https://data.food.gov.uk/regulated-products/food_authorisations), including limits for arsenic, lead and fluoride; electronic grade for etching needs trace metals in the parts per billion range, set in the buyer's specification.

Phosphoric acid solution is a class 8 corrosive, UN 1805, shipped in UN-marked IBCs, drums or lined ISO tanks, and needs a safety data sheet. An importer of more than one tonne a year should check UK REACH registration.

Worked duty example

For a made-up shipment of 20 tonnes of 85% technical-grade phosphoric acid in IBCs under 2809 20 00 00, add the £2,600 of freight and insurance to the £14,000 free-on-board price and customs sees £16,600. Duty on phosphoric acid is zero, leaving import VAT of £3,320, 20% of the customs value. For a VAT-registered buyer that is a cash-flow cost rather than a lasting one. The declaration also reports the quantity in kilograms of P2O5, the supplementary unit for this code. The duty and VAT guide walks through the calculation.

Inspection checklist

Strength: assay checked by acid-base titration and density measured with a calibrated hydrometer at the stated temperature on a sample from each IBC or tank, compared with the certificate, and the P2O5 content worked out from the assay so the supplementary unit on the declaration matches the goods.

Impurities: arsenic, lead, cadmium and mercury measured by ICP on each batch against the grade, fluoride by ion-selective electrode, sulphate and chloride by ion chromatography, iron against the specification, and colour on the platinum-cobalt scale by ISO 6271; electronic grade tested for trace metals by ICP-MS and filled in clean containers.

Containers: IBCs and drums UN-marked for class 8 packing group III, IBCs within their periodic test date, valves and lids sealed and tamper-evident, corrosive labels and GB CLP hazard labels in English, and a safety data sheet matching the grade shipped.

What goes wrong

Acid lots fail on strength, impurities and containers. Concentration is below the contracted 75% or 85%, so you pay for water; wet-process acid carries iron, sulphate, fluoride and heavy metals above a food or electronic specification; colour and turbidity show poor purification; and IBCs crack or leak when the wrong grade of polyethylene or an old cage is used.

Check assay by titration and density on each batch, test arsenic, lead, cadmium, fluoride, iron, sulphate and chloride against the grade, ask whether the acid is thermal or purified wet-process, inspect IBCs for UN marks, date and valve seals, and keep the certificate of analysis with the entry.

Cambridge China Bridge sources phosphoric acid for cleaning, metal finishing, food and fertiliser producers, including regular IBC or ISO tank programmes. See our container programmes.