Vat dyes are applied by using Sodium Hydrosulphite (sodium dithionate) as reducing agent and sodium hydroxide as an alkali. Some by-products of sodium hydrosulphite are acidic in nature, necessitating overdosing of sodium hydroxide over stoichiometric requirement. A few of the by-products formed are sulphur compounds like Na2S and NaHS, which pollute air through the formation of H2S. At the same time, the salts of sulphur in the form of sulphate and Sulphites (Na2SO3, NaHSO4, Na2SO4, Na2S2O3) contaminate sewage, lower its pH and show corrosive action on concrete pipes. Other problems associated with the use of sodium hydrosulphite are its cost and low storage stability.
Molecular formula: Na2S2O4
Appearance: Sodium Hydrosulfite is also known as sodium dithionite, and is white crystalline powder or yellowish. It is soluble in sodium hydroxide solution and slightly soluble in ethanol.Powdered anhydrous sodium hydrosulfite with a small amount of water may ignite in air by the heat of decomposition.
Product specifications:
| INDEX | 90% | 88% | 85% | Food Grade |
| Na2S2O4 | ≥90% | ≥88% | ≥85% | ≥85% |
| Fe | ≤20ppm | ≤20ppm | ≤20ppm | ≤20ppm |
| Zinc(Zn) | ≤1ppm | ≤1ppm | ≤1ppm | ≤1ppm |
| Other heavy metal
(calculated as Pb) | ≤1ppm | ≤1ppm | ≤1ppm | ≤1ppm |
| Water Insolubles | ≤0.05% | ≤0.05% | ≤0.05% | ≤0.05% |
| Shelf Life(month) | 12 | 12 | 12 | 12 |
Application:
1. Widely used in textile industry for vat dyeing, reduction cleaning, printing and stripping, textile textile bleaching.
2. It is also used in bleaching paper pulps, especially mechanical pulps, it’s the most fitable bleaching agent in pulps.
3. It is used in bleaching kaolin clay, fur bleaching and reductive whitening, bleaching of bamboo products and straw products.
4. It is used in mineral, the compound of thiourea and other sulphides.
5. It is used as reducing agent in chemical industry.
6. Sodium hydrosulfite food additive grade is used in foodstuffs, as bleaching agent and preservative in dried fruits, dried vegetable, vermicelli, glucose, sugar, rock sugar, caramel, candy, liquid glucose, bamboo shoots, mushrooms and canned mushrooms.
Packing: 50kg net in iron drums with double inner polybags.
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Product Categories : Sodium Hydrosulfite
