Sourcing sodium dithionite from China

Sodium dithionite duty and tariff controls

Read from the UK Trade Tariff on 29 September 2026, sodium dithionite falls within heading 2831, dithionites and sulphoxylates, under the sodium line 2831 10 00 00. Goods from China carry 0% duty, with no anti-dumping or countervailing duty and no suspension recorded. The table shows applications sharing this commodity line, rather than separate tariff subdivisions.

The UK Trade Tariff attaches import and export waste controls. If a proposed shipment from China is waste subject to notification controls, the exporter must apply to the competent authority in China for consent. Ask your customs broker to confirm whether the waste controls apply to the consignment and what documents are required; confirm export requirements separately for any waste return.

Confirm the composition and product identity using our guide to finding your commodity code. For other products within the heading, see dithionites and sulphoxylates.

Specify active assay and packaging

Specify sodium dithionite, also called sodium hydrosulphite, by active assay, agreed test method, insoluble matter and impurity limits relevant to your process. Ask the factory to declare stabilisers or other additives. Agree powder condition, pack material, closure, net weight and batch identification rather than accepting a trade name alone.

Ask for a batch certificate of analysis and the safety data sheet before ordering. Safety data sheets are required by UK REACH. Confirm the UK REACH registration position for your annual imports with HSE. Check the hazard classification and labelling before selling the product in Great Britain. Give the carrier the safety data sheet to review the proposed shipment arrangements.

Worked duty example

Illustrative example, not a quote: 25 tonnes of sodium dithionite for an industrial chemical distributor, illustrative only under 2831 10 00 00, invoiced at £15,000 free on board, with £2,000 of freight and insurance to the UK. The customs value is £17,000. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £17,000, so it is £3,400. With no duty, the only import tax is the VAT, which a VAT-registered importer can usually reclaim. The import duty and VAT guide explains each step.

Inspection checklist

Identity: check that the purchase specification, safety data sheet, batch certificate and package labels describe the same chemical and declared additives.

Assay: arrange independent analysis of representative batch samples against the agreed active assay, impurity limits and test method.

Packaging: check closures, liners, moisture damage, leakage, corrosion and caking before shipment and again on arrival.

Traceability: match package batch marks to the analysis certificate, check net weights and retain inspection records. Use an agreed sampling plan for the quality inspection.

What goes wrong

A batch can meet a generic grade description yet fail your process because its active assay, additives or insoluble matter differ from the approved sample. Moisture damage and caking are reasons to investigate before releasing stock. Agree arrival testing and how disputed batches will be held and assessed.

HSE warns that adding sodium dithionite to process vessels can cause serious injuries. Review handling arrangements against the safety data sheet before a production trial. A trial should establish process suitability as well as checking the certificate; an acceptable assay alone does not establish safe handling.

Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For repeat volumes, see container programmes.