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HS Code |
602476 |
| Chemicalname | Sodium Hydrosulfite |
| Chemicalformula | Na2S2O4 |
| Molarmass | 174.10 g/mol |
| Appearance | White or pale yellow crystalline powder |
| Odor | Faint sulfurous odor |
| Solubilityinwater | Soluble |
| Density | 2.19 g/cm3 |
| Meltingpoint | Decomposes before melting |
| Stability | Unstable in air |
| Casnumber | 7775-14-6 |
| Ph | 9-11 (1% solution) |
| Commonuses | Reducing agent in textile, paper, and photographic industries |
As an accredited Sodium Hydrosulfite factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Sodium Hydrosulfite is packaged in a 50 kg net weight blue plastic drum, featuring hazard labels and a tightly sealed lid. |
| Shipping | Sodium Hydrosulfite is shipped in tightly sealed containers, typically drums or bags, to protect against moisture and heat. Ensure proper labeling as a hazardous material. Transport in a cool, dry, and well-ventilated environment, away from oxidizers and acids. Follow regulations for chemical safety and emergency procedures during transit. |
| Storage | Sodium hydrosulfite should be stored in a cool, dry, and well-ventilated area, away from heat sources, moisture, and direct sunlight. Keep it in tightly sealed containers, protected from incompatible materials such as acids and oxidizers. Store away from combustible substances, and ensure emergency procedures and proper labeling are followed to minimize risk of fire or decomposition. |
Applications of Sodium Hydrosulfite in Industrial ManufacturingSodium hydrosulfite serves as a reducing agent in multiple industrial manufacturing segments. Our integrated production processes deliver reliable supply to customers in textile processing, paper pulping, leather finishing, kaolin clay bleaching, and chemical synthesis. We formulate and control quality based on the demands of downstream processes where this raw material directly impacts end-product appearance and performance. 1. Textile Dyeing and Textile PrintingTextile mills often use sodium hydrosulfite in vat dye reduction, indigo denim dyeing, and discharge printing for cotton, viscose, and blended fabrics. The powdered formulation enables robust color yield and repeatable results in open winch, jet, or pad-steam dyeing lines. As a reducing agent, it lowers vat dye to the soluble leuco state, ensuring complete fiber penetration and fast wash-off, especially in dark shades. In discharge printing, it creates design motifs by locally destroying pre-applied color. Appropriate use minimizes residual reducing agent, facilitates wastewater compliance, and supports high-throughput automatic dosing systems. Industry compliance standards
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2. Paper and Pulp BleachingPulp and paper mills utilize sodium hydrosulfite for brightness improvement and color stripping during mechanical pulp and deinked pulp processing. By reducing chromophoric groups such as quinones and lignin derivatives, it enhances optical whiteness and minimizes yellowing in printed newsprint, packaging paper, coated stock, and tissue paper. Our supplied grades enable stable slurry feeding to high-shear bleaching towers and continuous reactors, responding well to controlled pH and temperature adjustments for optimal brightness gain. Integration into mill operations requires full compliance with effluent discharge parameters to control sulfite load and AOX levels. Industry compliance standards
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3. Leather ProcessingSodium hydrosulfite provides reliable reduction in the bleaching of crust and vegetable-tanned leathers, removal of iron stains, and neutralization of oxidized patches during beamhouse and post-tanning operations. Tanners benefit from its high solubility, consistent performance at low temperatures, and compatibility with other auxiliary chemicals. The product enters aqueous float baths, supporting controlled lightening processes that enhance uniformity and minimize batch-to-batch shade variation. Proper dosage management prevents fiber damage or over-bleaching. Waste streams require attention to total reducing agent residues before discharge or recycling within water-saving tanneries. Industry compliance standards
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4. Kaolin Clay BleachingCeramic and pigment manufacturers rely on sodium hydrosulfite for the reductive bleaching of kaolin clays. The chemical effectively removes ferric iron stains and organic coloring matter present in crude kaolin, producing high-brightness pigment for paper coating and plastics compounding. It supports slurry-based bleaching under controlled agitation and automatic pH regulation, which is essential for uniform color improvement and minimal reversion. The reduction step enables downstream filtration, drying, calcining, or dispersion based on final pigment specifications. Our production lines supply consistent bulk quantities for integration with high-volume kaolin processing plants. Industry compliance standards
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5. Chemical Synthesis Intermediate in Pharmaceutical and Agrochemical IndustriesProcess development teams incorporate sodium hydrosulfite in reductive transformations, cleavage reactions, and sulfonation/deoxygenation steps for fine chemicals, pharmaceutical intermediates, and crop protection actives. Controlled use supports product purity in the multi-step synthesis of dye precursors, active pharmaceutical ingredients (APIs), and certain fungicides or herbicides. The reducing power under specified pH and temperature enables selective reaction of sensitive functional groups while minimizing side-product formation. We supply GMP-grade materials for regulated manufacturing flows where trace-level impurities, heavy metals, and variation in reduction rate all require close monitoring and documentation for regulatory submissions. Industry compliance standards
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Competitive Sodium Hydrosulfite prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8615371019725 or mail to sales7@bouling-chem.com.
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Tel: +8615371019725
Email: sales7@bouling-chem.com
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Sodium hydrosulfite, also called sodium dithionite, keeps finding its way into industrial processes for one reason: reliability. In textiles, it pulls double duty as both a reducing agent and a color remover. It takes a careful hand to craft sodium hydrosulfite that stands up to the needs of dye houses, paper mills, and the many corners of the chemical world that rely on it. The process starts at the reactor, and it only ends once the powder meets our specification checks and goes out the warehouse door.
We’ve been working directly with this product for years. Experienced operators watch color and reduction potential from every batch. This isn’t something that can be left to automation—there’s always a feel for how the slurry’s running when the temperatures spike during the reduction. Too much variation in the raw sodium formate, and you’ll chase your tail on consistency. Add a little excess to the process water and you get caking or unwanted side-reactions. Getting it right each time means closely managing the feedstock and the reaction’s temperature slope. Our sodium hydrosulfite consistently delivers a white, free-flowing powder, which signals purity and minimal oxidation.
We mainly offer two sodium hydrosulfite specifications: 85% and 90%. Both come as powders, but the 90% grade contains less moisture, which is crucial if transport or storage conditions might be rough. Factories that need more staying power in reducing action—like denim laundries or large-volume pulp bleaching lines—reach for the 90%. It dissolves more easily and leaves fewer residues in mixing tanks, especially in colder climates where moisture control is tricky.
Choosing between 85% and 90% comes down to budget, process sensitivity, and storage duration. Some customers save money by using 85% if their application tolerates a bit of moisture or they run everything in a climate-controlled facility. Others, handling huge runs or trickier dyes with variable wash loads, find the 90% grade quickly pays off by keeping reduction potential above the threshold for color removal, even after long storage. Process engineers tend to ask us for practical details: flow rates, dissolution rates, or impurity levels. We show them records of test-run results, not just stamped certificates.
This compound built much of its reputation in the world of textiles, especially for indigo dyeing and vat dyeing. Indigo’s stubbornness isn’t news to anyone who’s worked denim lines. Faced with tight color consistency, reduction strength matters more than broad specifications or marketing words. Sometimes it feels like half your yield depends on the right dissolve, the other half on the absence of metallic contaminants picking up unwanted shades. Sodium hydrosulfite gets the indigo into its leuco form so the fiber takes up dye, then a quick oxidation delivers that famous blue.
Factories running rotary drum machines or open-width ranges rely on the batch-to-batch predictability of reduction. Operators appreciate powder that pours, flows, and dissolves clean into process water. If clumps or dust slow the charge, costly downtime and scrap reprocessing follow. By controlling both crystal size and moisture during our own finishing, we ensure clean handling on the floor. We take pride in how many of our partners keep our packaging stacked in their prep rooms, trusting it for dozens of colors, not just indigo.
Paper and pulp industry workers know what a tough battle it is to get a uniform, bright product from recycled fiber. Sodium hydrosulfite enters at the de-inking and whitening stage, going after oxidized lignins and leftover dyes. Pulp lines need steady reduction over hours; a flash in the pan won’t do. Whether you're running deinking for newsprint, or brightening delicate high-grade office papers, reduction stability across shifts counts for more than any headline claim.
Our 90% grade, dust-free and bulk packed, typically goes into larger mills. Customers have told us they see faster decolourization, less residue, and fewer problems with product storage, especially during humid seasons when sticking and clumping have cost older operations lost batches before. All sodium hydrosulfite grades react with dissolved oxygen so packaging matters—our laminated sacks address both dust and moisture, cutting waste and exposure risk for everyone from warehouse to process floor. No manufacturer wants to see piles of hardened powder or residue plugging feeder systems. Real-world usage has shown our process control at packing makes a difference each season, not just in a sales brochure.
Municipal water treatment plants and specialty chemical users sometimes need reducing agents that work reliably in a wider range of pH and temperature. Sodium hydrosulfite finds a home in oxygen removal, heavy metal precipitation, and certain environmental cleanups where classical agents like sulfur dioxide introduce unwanted byproducts or require large-scale gas handling. In these settings, the compound’s short shelf life becomes important: enough reduction for the job, not left on the shelf to degrade.
Working directly with plant managers and technicians over the years, we’ve seen sodium hydrosulfite favored for its clean reduction pathway and limited odor profile compared to alternatives. Users demand quick dissolution—especially in remote or unmanned stations—so our 90% product, with lower water content, simplifies batch prep and reduces scaling, especially for small-scale water remediation jobs. Feedback led us to adapt our production, prioritizing easy opening and pourable powder. Over the years, fewer call-backs and better field reports on both our packaging and actual reactivity have pushed us to stick with these improvements.
In practice, some customers ask why sodium hydrosulfite, not sodium bisulfite or sulfite, for their application. The difference often comes down to how much reduction you need and how persistently you want to maintain that environment. Sodium hydrosulfite’s two active hydrogens give it a stronger push, which matters for challenging dyes, tough inks, or highly oxidized pulp. Sulfites or bisulfites have their place in less demanding applications or where mild reduction suffices.
For those managing iron or manganese removal in water, the choice sometimes leans toward sodium bisulfite. Paper makers and textile dyers, though, rarely see consistent results at the high throughput expected if they switch away from hydrosulfite. Sulfite or bisulfite solutions eventually bring about yellowing in cellulose, a problem our sodium hydrosulfite avoids due to its rapid reactivity. Steel pickling lines and electronics recyclers, on the other hand, sometimes lean on sodium hydrosulfite for clean, thorough reduction of mixed oxides, and for its lower tendency to introduce foreign anions.
Every product has trade-offs. We see firsthand that hydrosulfite, especially at higher purities, delivers repeatable results, provided storage conditions stay dry and cool. A sealed drum of our powder, kept below 25°C and away from moisture, will hold up for months without appreciable loss in reduction potential. Once opened, it handles day-to-day plant variations without fuss, while bulk solutions of other reductants often shift unpredictably over time.
Down on our floor, sourcing and selection of raw materials remain constant priorities. The sodium formate, sulfur dioxide, and caustic soda we pipe into our reactors have to hit strict purity targets—not just averages over time. Cheap sulfur dioxide loaded with trace metals or contaminated water ruins yield and muddy reduction ability. Our lab keeps a running check on key impurities, and years of fine-tuning batch composition have led to robust, trouble-free production at scale.
Grain shape, moisture absorbency, dust creation: these seem like shop floor trivia to outsiders but turn into headaches for operators who need to move tonnes a week without stoppages. Our operators regularly feed back on powder flow, clump resistance, and dissolve clarity. Over the years, we have upgraded mill screens twice, swapped bagging styles three times, and continually adjust time-at-temperature to deliver a predictable pour. Subtle gains in process handling show up in operator reports with fewer clogging and less powder loss.
Once batches scale above unit tonnage, plant managers expect every kilogram to perform. Sodium hydrosulfite’s sensitivity to air and moisture pushes manufacturers to invest in controlled environments. We run dedicated dehumidification and nitrogen blanket systems, not just for the finished product, but throughout bagging and loadout. Years ago, we learned the hard way: open-air packing meant shortened shelf life and more returns. Today’s system delivers what our QA team records at the mill: low-residual oxidized sulfur, few off-colour particles, and a clean break on every bag out the door.
Handling safety matters. Everyone using sodium hydrosulfite knows its reactivity with water calls for secure, correctly labeled packaging and dry storage. We fit every outbound ton with a tightly clamped liner and reinforced outer bag. This doesn’t just make life easier at the receiving dock—it keeps transport compliant with most major shipping requirements for reducing agents. Plant safety audits often point to proper segregation and quick cleanup protocols for spilled powder. Instructions stay simple: store in a cool, dry area away from acids and oxidizers. We avoid overpromising: this isn’t a benign material, but it’s a critical tool, and proper education plus packaging keeps risks low.
Field operators rely on product traceability as much as on published SDS or generic safety data. We code every lot with date, plant, and shift of production, and track samples back to the actual reaction record. Any real-world issues come back to us for post-mortem, with in-person visits, not just paperwork. This is what builds the long-term trust we see from our largest partners—real transparency, not just compliance paperwork.
Users keep driving our process development. The rapid shift to water-saving textile processes, for instance, cut old consumption volumes but raised the bar for reduction strength and purity. Higher dyeing temperatures and closed-loop washing bring more dissolved solids to manage, putting pressure on every ingredient in the reduction bath. Our lab and process engineers monitor how trace iron, copper, or organic residues from raw materials influence reduction, and we adjust our purification protocols accordingly. We stay in conversation with plant engineers charting unexpected results: a pallet kept next to a steam line, a month with sudden humidity swings onsite, or changes in incoming dye chemistry. These conversations shape our continual refinements to bulk packaging and storage recommendations.
Waste and sustainability questions now impact every chemicals workflow. We’ve moved aggressively to reduce fugitive emissions in the plant, minimize wastewater from our own lines, and partner with shipping agents who recover used packaging wherever regulations allow. We deal frankly with end users about realistic disposal options and the challenges of high-salt effluent inherent to powder reduction chemistry. Simple tricks, like metering powder into closed systems or increasing storage turnover to prevent caking, have reduced both waste and operating cost for many downstream users.
Global logistics have brought new headaches lately. Supply chain shocks, tighter transport regulations, and sharper traceability audits cut down on available margin but also favor true manufacturers. Because we control every step from incoming raw to outbound lot, we can respond faster to requests for trace documents, sudden changes in customer demand, or rerouted shipments. Working next to technical teams rather than far from the floor helps us catch problems before they scale. Keeping reliability up under pressure draws repeat business, not just price cuts.
Today’s users demand more than chemical performance; they look for partners in troubleshooting, efficiency, and compliance. We invest in pilot trials and laboratory simulation of client processes for every proposed formula tweak or packaging change. Test data from textile and pulp lines using our material feed directly back to process controls at the manufacturing plant. We don’t just run “typical” specs—we look at outliers, odd failures, and customer downtime, then adjust handling, crystal habit, or impurity cut-points accordingly.
Waste minimization, carbon footprint tracking, and digital inventory links are moving out of theory and now appear on client obligations daily. It’s not enough to promise sodium hydrosulfite of a certain grade by theory alone; every lot has to prove its value in real application, measured by downstream performance, operator feedback, and lifecycle cost. We see requests for collaboration on powder alternatives, safer bulk handling equipment, and even hybrid blending right on customer premises. While raw chemistry stays at the core, it’s the knowledge and flexibility from years of direct manufacturing experience that lets us meet new demands in an evolving market.
In the end, the true test is whether factories keep the lines moving, get the right shades, the right pulp brightness, or clean water to spec every shift. That kind of trust isn’t built by broad guarantees, but by solving real problems side by side—with the confidence that every drum leaving our plant represents not just specification compliance, but hard-won, daily-tested reliability.
