Sourcing zinc dithionite from China

Zinc dithionite duty and waste controls

Read from the UK Trade Tariff on 29 September 2026, heading 2831 covers dithionites and sulphoxylates. Zinc dithionite falls within the other line, 2831 90 00 00, carrying 0% duty for goods from China. The supplied tariff record lists no anti-dumping or countervailing duty and no suspension.

The tariff attaches import and export waste controls. For a consignment from China to England subject to waste notification controls, shipment can start only after consent from the Environment Agency and the other competent authorities involved. Ask your customs broker to confirm whether the material is waste and which controls apply, including before returning rejected material.

Confirm the composition and product description using our commodity code guide. Only the relevant other line is shown here because the supplied tariff has no separate zinc dithionite subdivisions. For the sodium product within this heading, see sodium dithionite sourcing.

Specify zinc identity and reducing strength

Name zinc dithionite explicitly in the purchase specification. Agree the active dithionite assay, zinc content, moisture, insolubles, particle size and any stabilising ingredients. Require the certificate of analysis to identify the batch, test methods and whether results are reported on a dry basis or as supplied. Approve a sample in your intended process before accepting production stock.

For Great Britain, check your UK REACH registration position, particularly when annual imports reach one tonne. Before placing the chemical on the market, ensure correct labelling and packaging. A safety data sheet is required for a hazardous chemical supplied for use at work. Ask the supplier for the sheet covering the actual composition, then agree handling, storage and transport arrangements with the receiving warehouse and freight provider.

Worked duty example

Illustrative example, not a quote: Illustrative order: one tonne of zinc dithionite in sealed drums under 2831 90 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: match the zinc dithionite specification, invoice, drum labels and batch certificate; investigate any description that names only a generic reducing agent.

Assay: arrange representative sampling by a suitably equipped laboratory and compare active content, zinc, moisture and insolubles with the agreed specification.

Packaging: check seals, closures, liners, net weight and batch markings; record leakage, damaged drums and visible moisture.

Documents: compare hazard labels with the safety data sheet and match the certificate to the delivered lot. Set the sampling scope through our quality inspection guide.

What goes wrong

A generic chemical description can hide a different reducing agent or an undeclared blend. Other possible failures include assay below the agreed value, excess insolubles, damaged seals and certificates that belong to another batch. A zinc content result alone does not establish the active dithionite content.

Keep suspect stock separate from accepted batches while the supplier and laboratory investigate. Agree acceptance tests and how rejected material will be handled before ordering. Check the waste controls with your broker before arranging a return shipment.

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.