Sodium Metabisulfite Export to Africa: Grades, Packaging, Ports and Documents

Buying sodium metabisulfite (Na₂S₂O₅, CAS 7681-57-4) for an African mine, utility or food processor is mostly a logistics and paperwork exercise once the specification is fixed. This article covers the grades and specifications you should confirm, the packaging and container options, the ports and trade terms we quote against, and the documents you should expect on delivery.

1. Grades and specifications

Confirm the grade and the parameters you actually need – not every application needs the highest assay or the tightest impurity limits.

Parameter	Typical industrial grade	Typical food grade
Assay (Na₂S₂O₅)	96 – 98% min	97% min (per monograph)
SO₂ content	About 65% min	About 65% min
Appearance	White to pale-yellow crystalline powder	White crystalline powder
pH (5% solution)	About 3.5 – 5.0	About 3.5 – 5.0
Iron	Per industrial specification	Low, tightly limited
Heavy metals (as Pb) / arsenic	Per industrial specification	Strictly limited to food-grade levels
Water-insoluble matter	Low	Low, tightly limited

Ask for a specification sheet and confirm that the batch COA reports the parameters that matter for your process – for mining, assay and iron; for food, heavy metals and arsenic.

2. Packaging and container loading

Packaging	Notes
25 kg PP/PE woven bags	Standard export packing; palletised or loose. Good for multi-site distribution and smaller dosing points.
1000 kg jumbo bags	Efficient for plant-scale dosing at mines and utilities; fewer handling steps.
Full container loads (20 ft / 40 ft)	Port-to-port supply; container load depends on packaging and palletisation – confirm the exact loaded tonnage per container.

Metabisulfite is hygroscopic and reacts with moisture and air, so packaging must be intact and the material kept dry through the supply chain. For food-grade material, confirm the packaging is suitable for food use.

3. Ports and trade terms

We quote to African discharge ports on an FOB or CIF basis. Common ports include:

Region	Example ports
Southern Africa	Durban, Cape Town, Beira, Maputo, Walvis Bay
East Africa	Mombasa, Dar es Salaam
West Africa	Tema, Takoradi, Lagos/Apapa, Cotonou, Abidjan
North Africa	Ports quoted case by case

Tell us the discharge port, the volume and whether you need FOB or CIF, and we will quote accordingly. For repeat buyers we can quote against an annual or quarterly volume so the grade, packaging and COA are consistent.

4. Documentation

Certificate of analysis (COA) per batch – the specification you agreed against.
Safety data sheet (SDS) – for handling, transport and compliance.
Certificate of origin where required for customs or preferential treatment.
Third-party inspection (for example SGS or BV) on request, for pre-shipment quality and quantity.
Transport classification – sodium metabisulfite is classified as a corrosive solid; the exact UN entry and class are given on the SDS.

5. Payment terms and lead time

Typical arrangements are a deposit by T/T with the balance against documents, or a letter of credit for larger projects. Lead time depends on the packaging and volume, plus transit time to your port; confirm both on the quotation. For mines and utilities running continuous processes, we recommend a schedule that keeps a safety stock at site, so a shipping delay never stops the plant.

6. Choosing a supplier for African projects

Confirms the grade, assay and impurity limits in writing.
Supplies per-batch COA and SDS.
Offers the packaging, ports and trade terms you need.
Can quote an annual or quarterly volume for consistent supply.
Is upfront about lead time and transit to your port.

Frequently Asked Questions

What grade of sodium metabisulfite do mines use?

Industrial grade, normally 96-98% assay, is the standard choice for cyanide destruction and flotation. Food grade (tighter heavy-metal limits) is used where a site also runs food or beverage operations.

What packaging is best for African mine sites?

1000 kg jumbo bags are usually the most efficient for plant-scale dosing; 25 kg bags suit smaller dosing points and multi-site distribution. Both can be shipped in full container loads.

Which African ports do you quote to?

Durban, Cape Town, Beira, Maputo, Walvis Bay, Mombasa, Dar es Salaam, Tema, Takoradi, Lagos/Apapa, Cotonou, Abidjan and others, on FOB or CIF terms.

What documents come with the shipment?

Certificate of analysis and safety data sheet per batch, certificate of origin where required, and third-party inspection on request.

Do you offer annual supply contracts?

Yes – we can quote against an annual or quarterly volume so the grade, packaging and COA stream stay consistent for your plant.