Sulfur dye reducer · low Fe
Na₂S·9H₂O for sulfur black dye manufacturers
Sulfur dyes (Sulphur Black 1, Sulphur Blue 7/15, Sulphur Brown) are insoluble until reduced. Our Sodium Sulfide Nonahydrate (CAS 1313-84-4) delivers the consistent S²⁻ ion concentration, low iron and stable alkalinity that denim mills, cotton dye houses and sulfur-dye formulators rely on for deep, repeatable blacks.
Why dye houses choose our Na₂S·9H₂O
Low iron (≤ 30 ppm)
Critical for clean, jet-black shades — iron contamination shifts hue to greenish-brown and dulls denim wash-down.
Stable ≥98% assay
Tight assay control means predictable dye-bath redox potential; you don't re-dose mid-cycle to chase shade.
Fast dissolution
Crystalline nonahydrate dissolves cleanly into the alkaline reducing bath — no dust, no exothermic spikes.
Typical dye-bath usage
- Sulphur Black 1 (denim): 80–120% on weight of dye
- Sulphur Blue 15: 70–100% OWD
- Pad-steam continuous: 25–40 g/L in chemical pad
- Exhaust dyeing: 4–8 g/L bath concentration
| Application | Sulfur / vat dye reduction |
| Assay (Na₂S·9H₂O) | ≥ 98% |
| Iron (Fe) | ≤ 30 ppm |
| Free alkali (as NaOH) | ≤ 0.5% |
| Sulphite + thiosulphate | ≤ 0.1% |
| Appearance | Off-white / pale-green crystals |
| Packing | 25 kg HDPE bag · 1 MT FIBC |
| MOQ | 1 × 20FT FCL (24 MT) |