Order yellow flakes, 60% Na2S minimum, in 25/50kg PP bags with PE liner (or 1000kg jumbo bags) for copper ore flotation and tanneries. Check COA: Na2S 60% min, water insoluble 0.5% max, Na2CO3 2% max, and Fe 50 ppm max on low-iron lots. Sodium sulfide is UN 1849 Class 8 corrosive, so DG booking is mandatory. A 20ft container takes about 25-28 tons, and shipping runs 20-45 days depending on your port.
Sodium sulfide (Na2S) is the reagent that makes a copper flotation plant run: it is the most common depressant used to separate copper from iron sulphides, and it is the traditional unhairing chemical in leather tanneries. China is the world's largest producer, which is why buyers across Africa and South America import sodium sulfide from Chinese plants. This guide covers the grade to order, the lab values that decide quality, and the dangerous-goods details that surprise first-time buyers.
1. Which grade to order
The commercial standard is yellow flakes, 60% Na2S minimum. Two sub-grades are commonly quoted:
| Grade | Typical spec | Who should order it |
|---|---|---|
| Standard yellow flakes | Na2S 60% min, Fe ≤ 200 ppm | Copper / cobalt flotation, dyeing, general reagent use |
| Low-iron yellow flakes | Na2S 60% min, Fe ≤ 50 ppm | Tanneries and hide processors - iron stains leather |
If you run a mine concentrator, standard grade is fine. If you run a tannery, order the low-iron grade — iron contamination turns wet-blue hides grey and is very hard to fix after the bath. When in doubt, tell your supplier your end use.
2. The COA values that decide quality
- Na2S ≥ 60% — the active content. Below this, you are paying for soda and water instead of reagent.
- Water insoluble ≤ 0.5% — suspended sludge that blocks flotation feed lines and dulls tanning liquor.
- Na2CO3 ≤ 2% — soda impurity; high levels change the alkalinity balance of your process bath.
- Fe ≤ 50 ppm (low-iron lots) — iron is the number that stains leather; never skip this line for tannery orders.
- Colour: clean yellow — black or grey flakes usually mean oxidation or long storage; reject them.
Always request the batch COA before payment, and a sealed sample before loading. Sodium sulfide degrades if moisture gets in, so also check the bags visually at loading.
3. HS code, dangerous-goods rules and packaging
Sodium sulfide (hydrated) is classified under HS 2830.10 and is a regulated dangerous good: UN 1849, Class 8 (corrosive). That means:
- DG booking is mandatory — most carriers treat it as a full DG shipment, with MSDS, proper marks and fumigation-compatible packaging
- It reacts with moisture and acids to release hydrogen sulfide gas (H2S) — toxic and flammable, so cargo must stay sealed and dry
- Warehouses at both ends need dry, ventilated storage, never stacked near acids
Packaging is 25/50 kg PP woven bags with PE liner, or 1000 kg jumbo bags. A 20ft container takes about 25–28 tons. Budget extra days at the port for DG documentation.
4. Shipping time to your port
- West Africa (Lagos, Tema, Abidjan, Cotonou): about 25–35 days
- East Africa (Mombasa, Dar es Salaam): about 20–30 days
- South America (Callao, Santos, Cartagena): about 35–45 days
Because it is Class 8, confirm with your line that your port accepts DG discharge — a few minor ports require trans-shipment or special notice periods.
5. The three most common problems
(1) Moisture damage en route — wet cargo releases H2S and cakes the flakes; insist on PE liners and dry container survey before loading. (2) Low active content — cheaper traders stretch Na2S with sodium carbonate; the Na2S line on the batch COA is non-negotiable. (3) Iron staining — for tanneries, a standard (not low-iron) lot will ruin hides; specify Fe ≤ 50 ppm in your purchase order, not just on a conversation.
SAIFENG supplies sodium sulfide 60% yellow flakes in standard and low-iron grades alongside sodium hydrosulfide (NaHS) 70% and gold-leaching reagents — the complete reagent package for concentrators and tanneries — to buyers across Africa and South America. Every inquiry is answered within 2 working hours.
View sodium sulfide & mining reagents Get a quote for your port