When sourcing sodium sulfite for industrial applications, understanding the detailed sodium sulfite specification is one of the most critical steps in the procurement process. Whether you are buying for a power plant boiler system, a textile finishing line, or a pulp mill, the wrong specification can lead to costly equipment corrosion, product defects, or even safety incidents. At Hailei Chemical, we have seen too many buyers overlook key quality parameters, only to face batch rejections and supply chain disruptions. This comprehensive guide breaks down everything you need to know about sodium sulfite specifications, chemical structure, application-driven requirements, and how to select a reliable sodium sulfite supplier that consistently delivers the quality you need.
Sodium sulfite (Na₂SO₃) is a white, crystalline or powdered inorganic reducing agent widely used across multiple heavy industries. It is available in two main solid forms: anhydrous (water-free) and heptahydrate (seven water molecules). The compound is moderately soluble in water, producing an alkaline solution, and is valued for its ability to react readily with oxygen, chlorine, and peroxides. This oxygen-scavenging property makes it indispensable in boiler water treatment, while its reducing strength supports pulp processing, textile bleaching neutralization, and photographic developing.
When you request a quote or review a certificate of analysis, the sodium sulfite specification will typically include a set of physical and chemical parameters. While exact requirements vary by application, the following core specifications are essential for every industrial buyer to understand.
The primary measure of quality is purity, expressed as percent sodium sulfite (Na₂SO₃) content. Typical industrial technical-grade anhydrous sodium sulfite specifications range from 96.0% to 98.0%. For applications demanding higher purity, photographic and analytical grades can exceed 99.0%. However, for most boiler water treatment and pulp applications, 96–98% purity is perfectly adequate. Hailei Chemical’s standard anhydrous sodium sulfite is consistently within this range, with typical batch results at 97% or above. The heptahydrate form naturally carries a lower Na₂SO₃ content (typically 60–62% due to water of crystallization), and the purity is calculated based on dry basis or as-is weight, so always confirm which reporting basis your supplier uses.
Sodium sulfite hydrolyzes in water to produce an alkaline solution. A 1% solution at 25°C typically has a pH between 9.0 and 10.5. This alkalinity is important for corrosion inhibition in boiler systems, but it can also affect processes where neutral conditions are required. Always specify the acceptable pH range if your process is sensitive. A narrow pH specification (e.g., 9.5–10.0) indicates a well-controlled manufacturing process with minimal free alkali contamination.
For power plant applications, iron content is a critical specification. Dissolved iron can deposit on heat exchanger surfaces and catalyze pitting corrosion. A typical industrial-grade sodium sulfite specification limits iron (Fe) to a maximum of 0.002% (20 ppm). High-purity grades may specify iron below 0.0005%. Heavy metals (as Pb) are usually limited to ≤0.001%. Chloride content is another concern, especially for stainless steel boiler systems where chloride-induced stress corrosion cracking is a risk. Many suppliers will specify chloride as ≤0.01% for boiler-grade sodium sulfite. Hailei Chemical’s standard product meets or exceeds these limits, and we provide full impurity profiles on every batch certificate.
For liquid formulation users, water-insoluble residues can clog injection nozzles and cause system fouling. The specification typically limits water-insolubles to ≤0.01% for high-grade material. Even technical grades should stay below 0.05%. Always confirm this parameter if you will be preparing on-site liquid solutions.
Sodium sulfite slowly oxidizes to sulfate when exposed to air and moisture. Proper packaging in sealed polyethylene-lined kraft paper bags (25 kg) or super sacks (500–1000 kg) is essential to preserve the product’s specification until point of use. Shelf life is generally 12 months under cool, dry storage conditions. Specification sheets often include a recommendation to retest after 6 months if long-term storage is expected.
Understanding the sodium sulfite structure helps explain why it performs so predictably in oxygen-scavenging and reducing applications. The anhydrous molecule consists of two sodium cations (Na⁺) and one sulfite anion (SO₃²⁻). The sulfite ion has a trigonal pyramidal geometry with the sulfur atom at the apex, bonded to three oxygen atoms. This structure makes the sulfur atom relatively electron-rich, giving sodium sulfite its strong reducing character. In aqueous solution, sulfite ions readily donate electrons to oxygen molecules, converting to sulfate (SO₄²⁻):
2 Na₂SO₃ + O₂ → 2 Na₂SO₄
This reaction is the cornerstone of boiler water deoxygenation. At elevated temperatures (above 100°C), the reaction is rapid, making sodium sulfite an effective and economical oxygen scavenger. In the heptahydrate form (Na₂SO₃·7H₂O), the same sulfite anion is surrounded by water molecules in the crystal lattice, which increases the formula weight and lowers the effective Na₂SO₃ content. For industrial buyers, the structural difference translates directly into shipping and handling considerations: anhydrous product delivers more active sulfite per kilogram shipped, reducing freight costs.
Different end uses demand different emphasis on specification parameters. Knowing which parameters matter most can save you money by avoiding over-specifying purity and under-specifying critical impurities.
In power plants and industrial boiler systems, the primary purpose of sodium sulfite is to remove dissolved oxygen down to parts-per-billion levels to prevent pitting corrosion. The key specifications here are:
Sodium sulfite is used in the sulfite pulping process and as a reducing agent in bleaching stages. Specification requirements include consistent purity, low heavy metals (to avoid discoloration of paper), and controlled pH. Sulfite liquor in pulping requires a specific ratio of free and combined SO₂, which is influenced by the sodium sulfite purity. Pulp mills often work with a narrow acceptance range of 96.5–97.5% purity to maintain process uniformity. Impurities like chloride and iron are less critical than in boiler water but still must be monitored to avoid process upsets.
After hydrogen peroxide bleaching of cotton and cotton-blend fabrics, residual peroxide can cause dyeing defects and fabric damage. Sodium sulfite neutralizes the excess peroxide quickly and without producing acidic byproducts. For this application, the textile finishing plant needs a product that dissolves completely and leaves no insoluble residues that could stain fabric. Water-insoluble matter is therefore the most strictly controlled specification, often capped at ≤0.02%. Purity can be in the 96–98% range, but the absence of foreign particles is critical.
In black-and-white photographic developing solutions, sodium sulfite acts as a preservative for the developing agent, preventing oxidation. Photographic-grade sodium sulfite specifications demand extremely high purity (≥99.0%) with strict limits on heavy metals, iron, and organic contaminants that could fog the film. This grade is not interchangeable with industrial boiler-grade material; attempting to use technical-grade sulfite in photography will lead to inferior image quality. For buyers in this sector, sourcing from a sodium sulfite supplier that can consistently deliver analytical-grade material is non-negotiable.
Sodium sulfite is sometimes added to lime-sulfide dehairing baths to improve hair removal efficiency and reduce sulfide demand. Leather processing facilities typically use technical-grade anhydrous sodium sulfite with a minimum purity of 96%. The main specification concerns are heavy metals (which could end up in finished leather) and the absence of insoluble particles that would mar leather surfaces.
While this buyer’s guide focuses on industrial specifications, a frequently asked question deserves a brief mention. What is sodium sulfite in shampoo? In personal care products, sodium sulfite functions as a reducing agent and antioxidant, helping to prevent color fading and extend shelf life by scavenging dissolved oxygen. The cosmetic-grade sodium sulfite specification is far more stringent than industrial grades: purity must be ≥99%, heavy metals essentially undetectable, and the material must meet pharmacopeia or cosmetic ingredient monograph standards. Industrial buyers should note that this is a completely different product category with a significantly higher price point, and it is not suitable for industrial applications due to cost. Hailei Chemical supplies industrial-grade sodium sulfite; for cosmetic-grade inquiries, we recommend specialized fine chemical distributors.
When you ask “where can i buy sodium sulfite,” you are likely looking for more than just a vendor with stock availability. You need a supplier that can provide consistent quality, full documentation, and reliable logistics. Here are six criteria to use when vetting a sodium sulfite supplier.
Every shipment should come with a certificate of analysis (CoA) that lists actual test results against the specification. Avoid suppliers that only provide a generic “typical properties” sheet. The CoA should include assay, iron, heavy metals, water-insolubles, pH, and any other parameters agreed in your purchase contract. Hailei Chemical issues a detailed CoA with every order, allowing your quality control team to verify the sodium sulfite specification before offloading.
Ask if the supplier is a manufacturer or a trader. Manufacturers generally have better control over specification consistency because they can adjust reaction conditions (sulfur dioxide absorption into sodium carbonate/sodium hydroxide solution) and purification steps. Hailei Chemical produces sodium sulfite at our modern plant in Weifang, Shandong, with full traceability from raw material reception to finished product shipping.
Look for ISO 9001 (quality management), ISO 14001 (environmental management), and applicable chemical industry certifications. For exports to Europe, REACH registration is mandatory. Our facility maintains these certifications and can accommodate customer-specific audits. Ask your potential supplier if they have recent audit reports available.
Industrial sodium sulfite is typically shipped in 25 kg woven polypropylene bags with inner polyethylene liners, or in 500–1000 kg flexible intermediate bulk containers (FIBCs). Confirm that the packaging is suitable for ocean freight if you are importing. Proper palletizing and shrink-wrapping prevent moisture ingress. Ask about stuffing density and container loading capacity to optimize freight costs. Hailei Chemical loads a maximum 25 tons of sodium sulfite per 20-foot container without pallets, or 20 tons with palletized packaging for easier unloading.
Given international shipping lead times of 4–8 weeks, you need a supplier with consistent production output and flexible inventory management. Inquire about minimum order quantities (MOQs), typical lead times, and the supplier’s track record for on-time delivery. Hailei Chemical maintains a buffer stock of anhydrous sodium sulfite, allowing us to ship within 7–10 working days from receipt of order and payment, subject to prior coordination.
A true partner will help you optimize specification selection and troubleshoot application issues. When contacting a potential supplier, ask whether they have chemists or application specialists who can advise on dosage rates for your boiler system or compatibility with other process chemicals. For buyers new to sodium sulfite, a knowledgeable sodium sulfite supplier can help you avoid costly specification mistakes.
The anhydrous form contains no water of crystallization, while heptahydrate contains seven water molecules per Na₂SO₃ unit. Anhydrous sodium sulfite has a higher effective sulfite content (96–98%) and is preferred where high reactivity and low shipping weight are needed. Heptahydrate crystals are larger, store with slightly better stability in humid environments, but contain only about 60% Na₂SO₃. For boiler water treatment, anhydrous is the standard.
No. Food-grade sodium sulfite (often used as a preservative and antioxidant) requires compliance with food chemicals codex standards and must have very low heavy metals. Industrial-grade product, even at 98% purity, is not safe or permitted for food use. Always specify the correct grade for your intended use.
Store in a cool, dry, well-ventilated area away from moisture and acids. Keep containers tightly sealed when not in use. Even under ideal conditions, gradual oxidation to sulfate will occur. Retesting is recommended after 6 months of storage. If the product has hardened or become lumpy, it may have absorbed moisture and partially oxidized, and its assay should be verified before use.
Yes. The CAS number for anhydrous sodium sulfite is 7757-83-7, and for sodium sulfite heptahydrate it is 10102-15-5. EINECS number is 231-821-4 for anhydrous. These identifiers are important for customs documentation and safety data sheets.
Sodium sulfite is classified as an irritant under GHS. It can cause respiratory irritation if inhaled as dust, and skin or eye irritation upon contact. Safety data sheets (SDS) should be reviewed and PPE (dust mask, gloves, safety glasses) used during handling. Specification-wise, this means your supplier should provide an up-to-date SDS and ensure the product is not excessively dusty if that poses a workplace hazard. Some customers request a maximum dusting potential specification, which we can address through granular product options.
Getting the sodium sulfite specification right from the start protects your processes, your equipment, and your bottom line. Whether you need technical-grade anhydrous sodium sulfite for high-pressure boilers, a controlled particle size for textile bleaching neutralization, or photographic-grade purity, the specification details matter. At Hailei Chemical, we take pride in delivering consistent quality backed by full documentation and expert support. Our team can help you navigate the specification maze and ensure you get exactly the right product for your application.
Ready to source sodium sulfite that meets your exact specification? Visit our sodium sulfite product page for more technical details, or request a quote directly. Our sales engineers will respond within one business day with a tailored offer, including a detailed specification sheet for your batch.
When sourcing industrial reducing agents, procurement professionals often face the decision: sodium hydrosulfite vs sodium sulfite. Both chemicals serve as powerful reducing agents, but their distinct chemistries, handling requirements, and application profiles make each suited to very different processes. Choosing the wrong product can lead to efficiency losses, safety incidents, and inflated operating costs. In this comprehensive buyer’s guide, we break down the key differences, examine technical specifications, review safety data sheets (SDS), and provide practical procurement insights to help you make an informed choice.
At the molecular level, sodium hydrosulfite (also called sodium dithionite, Na₂S₂O₄) and sodium sulfite (Na₂SO₃) differ fundamentally. Sodium hydrosulfite contains sulfur in an oxidation state of +3, while sulfite has sulfur at +4. This difference gives hydrosulfite a much stronger reducing capability, but also makes it more reactive, unstable, and hazardous. Sodium sulfite is a milder, more stable reducing agent that is easier to handle and store.
Key chemical properties at a glance:
These chemical profiles directly impact how each product is used in industrial settings. Hydrosulfite’s aggressive reactivity is essential for rapid bleaching operations, while sulfite’s stability and controlled release of sulfite ions make it ideal for long-duration processes like boiler water deoxygenation.
Sodium hydrosulfite is the reducing agent of choice when high reduction power and speed are critical. It is widely used in:
Its ability to reduce dyes and colored impurities rapidly makes it indispensable in these color-sensitive sectors. However, the instability of hydrosulfite demands stringent storage (cool, dry, airtight conditions) and short shelf life.
Sodium sulfite’s moderate and stable reducing action finds a different set of heavy industrial uses:
A procurement manager for a power plant will find sodium sulfite essential for corrosion control, while a textile finishing plant manager may need both chemicals for different steps in their workflow. Understanding these specific roles is critical when comparing sodium hydrosulfite vs sodium sulfite.
When procuring sodium sulfite, technical buyers must verify that the offered grade meets their process tolerances. Typical industrial grade sodium sulfite specifications from a reliable supplier like Weifang Hailei Fine Chemical Co., Ltd. include:
| Parameter | Specification (Typical) |
|---|---|
| Purity (Na₂SO₃) | ≥ 96.0% (anhydrous), ≥ 98.0% for certain grades |
| Iron (Fe) | ≤ 0.005% |
| Water Insoluble Matter | ≤ 0.03% |
| pH (5% aqueous solution) | 9.0 – 10.5 |
| Heavy Metals (as Pb) | ≤ 0.002% |
| Appearance | White to slightly yellowish crystalline powder or granules |
Buyers should pay special attention to iron content and water insolubles, as these can foul boiler internals or discolor pulps. Sodium sulfite is available in anhydrous (Na₂SO₃) and heptahydrate (Na₂SO₃·7H₂O) forms, with the anhydrous grade offering higher active content and lower shipping weights—a key logistics consideration. For detailed technical data, download the full specification sheet on our sodium sulfite product page.
Understanding how sodium sulfite in water behaves is essential for safe and effective use. Sodium sulfite is highly soluble: about 28 grams dissolve in 100 mL of water at 20°C, forming a clear, mildly alkaline solution (pH ~9.5 for a 5% solution). The dissolution process is slightly endothermic, causing a minor temperature drop.
In boiler water treatment, the sulfite ion (SO₃²⁻) reacts with dissolved oxygen to form sulfate (SO₄²⁻), a stable and non-corrosive byproduct. The reaction is fast at elevated temperatures (>80°C), making sulfite an excellent oxygen scavenger. A typical maintenance dosage is 30-60 mg/L of sodium sulfite, depending on feedwater oxygen levels and system metallurgy. Overdosing can increase boiler water solids, so precise control is recommended.
When preparing solutions, always add sodium sulfite to water slowly with agitation, wearing appropriate PPE. Avoid direct contact with acids, as this can release toxic sulfur dioxide gas. For large-volume users, Hailei Chemical can provide soluble bag or pre-dissolved delivery advice to simplify handling.
Industrial safety managers rely on the Safety Data Sheet (SDS) to assess hazards and establish safe handling protocols. The sodium sulfite SDS classifies the product as a skin and eye irritant, as well as a respiratory irritant. Typical GHS hazard statements include H315 (Causes skin irritation), H319 (Causes serious eye irritation), and H335 (May cause respiratory irritation). The corresponding GHS pictogram is the exclamation mark.
In contrast, sodium hydrosulfite carries more severe hazards: it is classified as a self-heating substance (H251), can ignite spontaneously if exposed to moist air, and releases toxic sulfur dioxide fumes upon decomposition. Its SDS will show both the flame (GHS02) and exclamation mark (GHS07) pictograms, along with stricter storage and handling requirements.
Key safety recommendations for sodium sulfite:
The SDS should always be consulted before use. Hailei Chemical provides compliant SDS documentation with every shipment, ensuring full regulatory transparency for importers and end-users.
While this guide focuses on industrial technical grades, the keyword sodium sulphite in food frequently appears in procurement conversations. Sodium sulfite is recognized as food additive E221 and functions as a preservative and antioxidant in certain foods such as dried fruits, fruit juices, and wine making. It prevents browning and microbial growth. However, food-grade sodium sulfite must meet strict purity criteria (typically ≥ 98.5%, heavy metals < 5 ppm, etc.) and is supplied under a separate certification program.
Hailei Chemical’s standard sodium sulfite is a technical grade product intended for industrial applications like water treatment, pulp, and textiles. If your facility requires food-grade material, please contact our technical team to discuss feasibility and custom specification options. We always advise buyers to clearly state intended use to ensure you receive the appropriate grade, avoiding costly rejections at customs.
When evaluating sodium hydrosulfite vs sodium sulfite, total cost of ownership often tips the scale toward sulfite for many applications. Sodium hydrosulfite is typically 2–3 times more expensive per ton, has tighter storage constraints (often requiring air-conditioned warehousing), and a shorter shelf life (6-12 months) compared to sodium sulfite’s 2-year shelf life when stored properly. Shipping also differs: hydrosulfite is classified as a hazardous material (Class 4.2 self-heating substance) under international transport regulations, triggering stricter packaging and handling surcharges. Sodium sulfite is generally classed as non-dangerous for transport (unless mixed with certain additives), simplifying logistics and lowering freight costs.
From a supply security perspective, sodium sulfite benefits from a more mature and diversified global production base. Chinese manufacturers like Hailei have robust capacity, ensuring stable quarterly pricing and reliable container lead times. For high-volume consumers such as power plants or pulp mills, the consistent quality and cost stability of sodium sulfite make it a safer long-term procurement choice.
Weifang Hailei Fine Chemical Co., Ltd. has been a trusted partner for industrial chemical buyers worldwide for over a decade. Our sodium sulfite is produced in modern ISO-certified facilities to consistent purity levels, with regular third-party testing. We offer flexible packaging options—25 kg woven bags, 1,000 kg supersacks, or custom requests—and assist with all export documentation, including Certificate of Analysis (CoA) and MSDS in multiple languages.
Our technical support team can help you optimize dosage, compare material cost per unit of active reducing power, and even arrange trial samples for your plant trials. Visit our dedicated sodium sulfite page for full product details and a downloadable preliminary specification.
Whether you are finalizing your boiler water treatment program, scaling up a textile desizing line, or evaluating alternative suppliers, the right choice between sodium hydrosulfite and sodium sulfite begins with accurate technical data and reliable supplier support. Hailei Chemical is ready to deliver the high-quality sodium sulfite you need, on time and on spec.
Request a competitive quote today or speak with one of our industrial chemical specialists for personalized assistance in selecting the optimal reducing agent for your process.
When purchasing industrial chemicals, precision is everything. For boiler water treatment specialists and power plant chemical buyers, the sodium sulfite molecular weight is not just a number on a data sheet—it is the foundation of accurate dosing, cost control, and system protection. Sodium sulfite (Na₂SO₃) acts as a highly effective oxygen scavenger, but its performance hinges on understanding stoichiometric ratios that begin with its molecular weight. Whether you are comparing it to sodium metabisulfite vs sodium sulfite or clarifying a search for what is sodium sulfate potas, the data behind the formula matters when you are deciding where to buy sodium sulfite in bulk. In this article, we examine how molecular weight influences real-world procurement and application decisions.
Sodium sulfite is an inorganic sodium salt of sulfurous acid, represented by the chemical formula Na₂SO₃. It appears as a white crystalline powder that is highly soluble in water, with a slightly sulfurous odor. The compound is available in two primary forms: anhydrous sodium sulfite (Na₂SO₃) and sodium sulfite heptahydrate (Na₂SO₃·7H₂O). Each has a distinct molecular weight due to the water of crystallization.
The anhydrous form is the commercial standard for most industrial applications because it offers higher active content per unit mass. For procurement, knowing the correct molecular weight is critical when calculating the amount of active oxygen-scavenging substance you receive per shipment, especially if you are comparing prices between suppliers who may provide different hydrates.
In boiler water treatment, sodium sulfite functions as an oxygen scavenger through a direct chemical reaction with dissolved oxygen:
2Na₂SO₃ + O₂ → 2Na₂SO₄
From this stoichiometry, one mole of oxygen (O₂, molecular weight 32.00 g/mol) reacts with two moles of sodium sulfite. Therefore, to remove 1 g of dissolved oxygen, you need theoretically 7.88 g of anhydrous sodium sulfite (since 2 × 126.04 / 32.00 = 7.875). However, industrial-grade sodium sulfite typically has a purity of 96–98%, which must be factored into the dosage formula.
Dosing without considering molecular weight leads to either underfeeding—risking pitting corrosion in boiler tubes—or overfeeding, wasting money and increasing dissolved solids that require more blowdown. Every procurement professional dealing with sodium sulfite molecular weight data can translate a specification sheet into reliable operational efficiency.
Consider a 100 MW power plant that must treat 500 m³ of feedwater per hour, with an average dissolved oxygen content of 5 mg/L. The hourly oxygen load equals 2,500 g. The theoretical minimum sodium sulfite requirement is 2,500 × 7.875 = 19,687.5 g, or nearly 20 kg per hour. With a product of 97% purity, the actual amount needed becomes approximately 20.3 kg/h. Over a year, even a 5% error in molecular-weight-based calculation can accumulate into tens of thousands of dollars in chemical waste or damage repair.
Explore our sodium sulfite specifications and purity grades for boiler water applications.
Many buyers confuse sodium metabisulfite (Na₂S₂O₅) with sodium sulfite, especially when sourcing an affordable oxygen scavenger. The search query sodium metabisulfite vs sodium sulfite reflects a real evaluation many engineers perform. The molecular weight difference is crucial here because metabisulfite reacts in water to form sulfite:
Na₂S₂O₅ + H₂O → 2NaHSO₃ (which further dissociates to provide sulfite ions)
The effective sulfite (SO₃²⁻) molecular weight per gram of product is not directly comparable. Anhydrous sodium sulfite has a molecular weight of 126.04 g/mol and provides one mole of sulfite. Sodium metabisulfite (molecular weight 190.11 g/mol) yields two moles of bisulfite, but the effective scavenging capacity is not simply double. Empirical equivalence factors are used: approximately 1.5 parts of metabisulfite are needed to replace 1 part of sulfite by weight, all else being equal. For accurate boiler treatment, stick to sulfite products with defined molecular weight parameters—this avoids the variability of the metastable metabisulfite solution.
Understanding sodium metabisulfite vs sodium sulfite from a molecular weight perspective helps procurement teams avoid the pitfall of purchasing a cheaper product that delivers less active sulfite per ton.
A common point of confusion arises between sodium sulphate (Na₂SO₄) and sodium sulfite. The spellings are similar, and both appear in industrial water chemistry. However, the sodium sulphate vs sodium sulfite distinction is fundamental: sulfate is the oxidized end-product after sulfite has done its job, and it has no oxygen-scavenging capability. Sodium sulfate molecular weight is 142.04 g/mol, compared to 126.04 g/mol for sulfite. When analyzing boiler water chemistry, the presence of sulfate indicates that sulfite has successfully reacted with oxygen. Buyers who mistakenly purchase sodium sulfate instead of sodium sulfite lose all scavenging protection, so verifying the CAS number (7757-83-7 for sulfite vs. 7757-82-6 for sulfate) and molecular weight on a certificate of analysis is essential.
Some users enter the phrase what is sodium sulfate potas into search engines. This appears to be a typographical blending of sodium sulfate and potassium or potash. There is no standard chemical called “sodium sulfate potas.” It likely originates from a mis-typed query asking about sodium sulfate in combination with potassium salts. Potash refers to potassium carbonate, and sodium sulfate is a distinct compound. If you arrived here looking for sodium sulfate’s role in potash processes, it is sometimes used as a filler or in mineral processing, but it has no relevance to oxygen scavenging. For boiler water treatment, sodium sulfite is the correct choice, and its molecular weight of 126.04 g/mol ensures you are ordering the right chemistry.
When you are ready to where to buy sodium sulfite, the specification sheet should clearly state the molecular weight and purity. Industrial grades range from 96% to 98% Na₂SO₃ content, with the balance being mainly sodium sulfate and residual water. The effective “available sulfite” molecular weight per gram of delivered product can be calculated as:
Effective weight fraction = Purity × (Molar mass of sulfite ion / Molar mass of Na₂SO₃)
For a 97% pure product, not all that mass is active scavenger because some impurities exist. Still, the molecular weight you use for stoichiometry should be based on the certified assay. Reputable suppliers, like Hailei Chemical, provide detailed certificates of analysis with assay, molecular weight, and hydrate form clearly indicated. This transparency allows you to accurately compare quotes and ensure the product meets ASME or VGB guidelines for boiler water chemistry.
Download a sample COA and see typical sodium sulfite purity levels from Hailei Chemical.
Finding a reliable source for industrial sodium sulfite involves more than a quick internet search. Use the following criteria when shortlisting suppliers:
Hailei Fine Chemical, based in Weifang, China, is a leading exporter of sodium sulfite anhydrous. Our product consistently delivers 96–98% purity with a molecular weight of 126.04 g/mol, and we support our customers with pre-shipment samples, documentation for customs, and flexible logistics solutions. Whether your interest lies in the sodium sulfite molecular weight for precise dosing or in comparing sodium metabisulfite vs sodium sulfite, our technical team can help you make an informed decision.
From boiler water oxygen scavenging to pulp processing and textile bleaching, sodium sulfite’s performance starts with its fundamental chemical identity. The molecular weight of 126.04 g/mol for the anhydrous form is the key that unlocks accurate usage rates, cost comparisons, and quality verification. Avoiding confusion between sodium sulphate vs sodium sulfite, or understanding the obscure query what is sodium sulfate potas, all reinforce how critical it is to order the right chemical. When you know where to buy sodium sulfite and what specifications to demand, you gain control over your process and your budget.
Get in touch with Hailei Chemical today for a competitive quote on bulk sodium sulfite. Let us show you how consistent quality and clear specification data support your long-term boiler reliability.
Request Your Sodium Sulfite Quote Now
For procurement managers and chemical engineers, understanding a detailed sodium sulfite specification is the foundation of safe, efficient, and cost-effective operations. Whether you are sourcing oxygen scavengers for high-pressure boiler systems or bleaching neutralizers for textile finishing, the technical data sheet dictates performance, storage stability, and compliance. A clear sodium sulfite specification reduces supply chain risk, prevents unplanned downtime, and ensures you receive a product that exactly matches your process requirements. This comprehensive guide deciphers every critical parameter, compares grades, and explains how to evaluate supplier documentation with confidence.
A generic purchase of “sodium sulfite” is never sufficient for demanding industrial environments. The difference between a 96% purity anhydrous powder and a 60% heptahydrate crystalline material affects dosing rates, corrosion control, and even regulatory compliance. In boiler water treatment, a poorly specified product may leave residual oxygen that accelerates pitting in steam circuits. In pulp processing, off-spec sulfite can alter pulp brightness and increase downstream bleaching costs. That is why leading power plants, pulp mills, and textile houses place the sodium sulfite specification at the core of their procurement framework—it is the measurable promise of quality before the first kilogram is shipped.
A typical certificate of analysis for sodium sulfite includes several key indicators. Understanding each one ensures you compare like-for-like across suppliers and avoid hidden cost pitfalls.
The sodium sulfite structure (Na₂SO₃) is a white, crystalline or powdered salt composed of two sodium cations and one sulfite anion. The sulfite ion (SO₃²⁻) is the active reducing agent that consumes dissolved oxygen, neutralizes residual peroxides, and functions as a preservative. Specifications always state the assay—the actual percentage of Na₂SO₃ in the material. For industrial applications, a purity of 96–98% for anhydrous grade is the benchmark, while heptahydrate (Na₂SO₃·7H₂O) typically assays around 60% Na₂SO₃ content, with the balance being water of crystallization. A lower assay forces you to handle and pay for more inert material, increasing freight costs and storage volume.
The primary sodium sulfite specification is the Na₂SO₃ content. For boiler water treatment, a minimum 96% purity ensures efficient oxygen removal with predictable dosing. Photographic-grade sodium sulfite often demands ≥98% purity to avoid streaks or fog on imaging materials. When comparing offers, always ask whether the purity is expressed on an “as is” or “dry basis”—this can reveal hidden moisture that dilutes the active ingredient.
Sodium sulfite is supplied as a white crystalline powder or granular solid. The specification will describe it as “white free-flowing powder” or “colorless crystals.” Any off-white or yellowish tint indicates oxidation to sodium sulfate or the presence of iron, which can stain pulp and textiles. Particle size distribution matters too: fine powders dissolve faster in cold water makeup for boilers, while granular forms minimize dusting and improve handling safety in large-scale batching operations.
A 1% or 5% aqueous solution of sodium sulfite is alkaline, typically with a pH of 9.0–10.5. This alkaline nature helps neutralize acidic components in boiler water but must be factored into overall water chemistry. A specification sheet that lists pH gives you an early indication of the product’s consistency and possible contamination by free alkali or sulfate.
For potable water or food-contact applications, trace heavy metals like lead, arsenic, and iron are tightly controlled. Even in industrial steam generation, iron content above 20 ppm can foul heat transfer surfaces or catalyze oxygen corrosion. A robust sodium sulfite specification will quantify Fe, Pb, As, and chloride levels, allowing you to assess long-term deposit risks. High-purity grades often guarantee Fe ≤ 0.002% and chloride ≤ 0.01%.
Undissolved solids can clog metering pumps and spray nozzles. Specifications may include “water insoluble matter” typically ≤0.05% for premium grades. If your application requires clear, sediment-free solutions—such as in photographic developers or textile bleaching baths—this figure becomes non-negotiable.
Sodium sulfite is traded predominantly in two forms, and choosing the wrong one can double your shipping costs or sabotage your process.
When you review a supplier’s data sheet, confirm which form is being offered and whether the assay accounts for hydration water. Many procurement errors stem from mistaking a heptahydrate price for an anhydrous equivalent. Always normalise delivered cost to the Na₂SO₃ basis for accurate comparison.
In powerhouse chemistry, dissolved oxygen is enemy number one. A precise sodium sulfite specification is essential because the oxygen-scavenging reaction is stoichiometric: 7.88 ppm of Na₂SO₃ is required to remove 1 ppm of dissolved O₂. If your product assays only 90% purity, you must dose 9% more chemical, increasing treatment costs and adding unnecessary sodium sulfate to the boiler water—raising blowdown frequency and fuel losses. A high-purity product like high-purity sodium sulfite for boiler water oxygen scavenging from Hailei Chemical enables slim and accurate dosing, minimizes sulfite sludge, and extends boiler tube life.
Additionally, boiler-grade sodium sulfite specifications should include a rapid dissolution rate. At feedwater temperatures of 60–80°C, full solubility must be reached within minutes to prevent undissolved particles from depositing in economizers. Look for “solubility: >20 g/100 mL water at 20°C” on the data sheet as a baseline.
Global buyers rely on standardized benchmarks to qualify suppliers. Common references in a sodium sulfite specification include:
Suppliers who can provide an analysis certificate aligned with these standards demonstrate robust quality management systems. Request ISO 9001 documentation and, for power generation buyers, third-party lab verifications that confirm compliance with pressure part protection guidelines.
When you ask “where can i buy sodium sulfite” that truly meets your spec, the answer often lies in the granularity of the supplier’s data. A trustworthy sodium sulfite supplier will offer:
At Hailei Chemical, our technical sales team helps you interpret every line of the sodium sulfite for industrial applications specification against your operational KPIs. This partnership approach prevents over-specifying (and overpaying) or under-specifying and risking process failure.
While heavy industries dominate procurement volumes, some buyers wonder: what is sodium sulfite in shampoo? In cosmetic formulations, sodium sulfite acts as a reducing agent, most notably in hair straightening treatments where it breaks disulfide bonds in keratin. For these personal-care uses, the specification is ultra-stringent: assay ≥98%, mercury <1 ppm, and microbial limits to ensure consumer safety. Although this market is niche compared to boiler treatment, the same analytical rigour applies. Cosmetics manufacturers often order small quantities of the highest purity grades, demonstrating that the sodium sulfite specification always dictates the application’s success.
It includes main content (Na₂SO₃ purity), appearance, pH, heavy metals (Fe, Pb, As), chloride, water insolubles, and for heptahydrate, water of crystallization. Some sheets also list sulfate content, particle size, and bulk density.
Request a pre-shipment sample for third-party lab analysis. Standard analytical methods include iodometric titration for sulfite content and ICP-OES for trace metals. Reputable suppliers will gladly provide a certificate of analysis from an accredited laboratory.
Not necessarily. Anhydrous offers higher activity and lower freight cost per active kilogram, making it the default for boiler and pulp users. Heptahydrate can be advantageous in cold regions where it is less prone to caking, and where the water addition is not detrimental to the process.
Direct-source manufacturers like Hailei Chemical offer sodium sulfite that complies with GB/T 9005, ACS, and other international standards. Consolidating supply with a manufacturer who exports regularly to your region ensures consistent quality and container-load economics.
Weifang Hailei Fine Chemical Co., Ltd. provides a fully transparent sodium sulfite specification with every shipment. Our anhydrous sodium sulfite is produced under stringent quality controls, yielding a 96–98% pure white powder engineered for the most demanding boiler water, pulp bleaching, and textile processing operations. We export to over 30 countries, offering flexible packaging, reliable logistics, and the technical support that large-scale industrial buyers require.
When your process depends on a precise chemical input, do not gamble with ambiguous data sheets. For a tailored quotation and to discuss your specific requirement parameters, visit our product page or reach out directly. Our specialists will help you navigate every aspect of the sodium sulfite specification to secure optimal performance and cost-efficiency.
Request a quote for high-purity sodium sulfite today and experience the difference a true specification partner can make.
When sourcing industrial reducing agents, procurement professionals often face the decision: sodium hydrosulfite vs sodium sulfite. Both chemicals serve as powerful reducing agents, but their distinct chemistries, handling requirements, and application profiles make each suited to very different processes. Choosing the wrong product can lead to efficiency losses, safety incidents, and inflated operating costs. In this comprehensive buyer’s guide, we break down the key differences, examine technical specifications, review safety data sheets (SDS), and provide practical procurement insights to help you make an informed choice.
At the molecular level, sodium hydrosulfite (also called sodium dithionite, Na₂S₂O₄) and sodium sulfite (Na₂SO₃) differ fundamentally. Sodium hydrosulfite contains sulfur in an oxidation state of +3, while sulfite has sulfur at +4. This difference gives hydrosulfite a much stronger reducing capability, but also makes it more reactive, unstable, and hazardous. Sodium sulfite is a milder, more stable reducing agent that is easier to handle and store.
Key chemical properties at a glance:
These chemical profiles directly impact how each product is used in industrial settings. Hydrosulfite’s aggressive reactivity is essential for rapid bleaching operations, while sulfite’s stability and controlled release of sulfite ions make it ideal for long-duration processes like boiler water deoxygenation.
Sodium hydrosulfite is the reducing agent of choice when high reduction power and speed are critical. It is widely used in:
Its ability to reduce dyes and colored impurities rapidly makes it indispensable in these color-sensitive sectors. However, the instability of hydrosulfite demands stringent storage (cool, dry, airtight conditions) and short shelf life.
Sodium sulfite’s moderate and stable reducing action finds a different set of heavy industrial uses:
A procurement manager for a power plant will find sodium sulfite essential for corrosion control, while a textile finishing plant manager may need both chemicals for different steps in their workflow. Understanding these specific roles is critical when comparing sodium hydrosulfite vs sodium sulfite.
When procuring sodium sulfite, technical buyers must verify that the offered grade meets their process tolerances. Typical industrial grade sodium sulfite specifications from a reliable supplier like Weifang Hailei Fine Chemical Co., Ltd. include:
| Parameter | Specification (Typical) |
|---|---|
| Purity (Na₂SO₃) | ≥ 96.0% (anhydrous), ≥ 98.0% for certain grades |
| Iron (Fe) | ≤ 0.005% |
| Water Insoluble Matter | ≤ 0.03% |
| pH (5% aqueous solution) | 9.0 – 10.5 |
| Heavy Metals (as Pb) | ≤ 0.002% |
| Appearance | White to slightly yellowish crystalline powder or granules |
Buyers should pay special attention to iron content and water insolubles, as these can foul boiler internals or discolor pulps. Sodium sulfite is available in anhydrous (Na₂SO₃) and heptahydrate (Na₂SO₃·7H₂O) forms, with the anhydrous grade offering higher active content and lower shipping weights—a key logistics consideration. For detailed technical data, download the full specification sheet on our sodium sulfite product page.
Understanding how sodium sulfite in water behaves is essential for safe and effective use. Sodium sulfite is highly soluble: about 28 grams dissolve in 100 mL of water at 20°C, forming a clear, mildly alkaline solution (pH ~9.5 for a 5% solution). The dissolution process is slightly endothermic, causing a minor temperature drop.
In boiler water treatment, the sulfite ion (SO₃²⁻) reacts with dissolved oxygen to form sulfate (SO₄²⁻), a stable and non-corrosive byproduct. The reaction is fast at elevated temperatures (>80°C), making sulfite an excellent oxygen scavenger. A typical maintenance dosage is 30-60 mg/L of sodium sulfite, depending on feedwater oxygen levels and system metallurgy. Overdosing can increase boiler water solids, so precise control is recommended.
When preparing solutions, always add sodium sulfite to water slowly with agitation, wearing appropriate PPE. Avoid direct contact with acids, as this can release toxic sulfur dioxide gas. For large-volume users, Hailei Chemical can provide soluble bag or pre-dissolved delivery advice to simplify handling.
Industrial safety managers rely on the Safety Data Sheet (SDS) to assess hazards and establish safe handling protocols. The sodium sulfite SDS classifies the product as a skin and eye irritant, as well as a respiratory irritant. Typical GHS hazard statements include H315 (Causes skin irritation), H319 (Causes serious eye irritation), and H335 (May cause respiratory irritation). The corresponding GHS pictogram is the exclamation mark.
In contrast, sodium hydrosulfite carries more severe hazards: it is classified as a self-heating substance (H251), can ignite spontaneously if exposed to moist air, and releases toxic sulfur dioxide fumes upon decomposition. Its SDS will show both the flame (GHS02) and exclamation mark (GHS07) pictograms, along with stricter storage and handling requirements.
Key safety recommendations for sodium sulfite:
The SDS should always be consulted before use. Hailei Chemical provides compliant SDS documentation with every shipment, ensuring full regulatory transparency for importers and end-users.
While this guide focuses on industrial technical grades, the keyword sodium sulphite in food frequently appears in procurement conversations. Sodium sulfite is recognized as food additive E221 and functions as a preservative and antioxidant in certain foods such as dried fruits, fruit juices, and wine making. It prevents browning and microbial growth. However, food-grade sodium sulfite must meet strict purity criteria (typically ≥ 98.5%, heavy metals < 5 ppm, etc.) and is supplied under a separate certification program.
Hailei Chemical’s standard sodium sulfite is a technical grade product intended for industrial applications like water treatment, pulp, and textiles. If your facility requires food-grade material, please contact our technical team to discuss feasibility and custom specification options. We always advise buyers to clearly state intended use to ensure you receive the appropriate grade, avoiding costly rejections at customs.
When evaluating sodium hydrosulfite vs sodium sulfite, total cost of ownership often tips the scale toward sulfite for many applications. Sodium hydrosulfite is typically 2–3 times more expensive per ton, has tighter storage constraints (often requiring air-conditioned warehousing), and a shorter shelf life (6-12 months) compared to sodium sulfite’s 2-year shelf life when stored properly. Shipping also differs: hydrosulfite is classified as a hazardous material (Class 4.2 self-heating substance) under international transport regulations, triggering stricter packaging and handling surcharges. Sodium sulfite is generally classed as non-dangerous for transport (unless mixed with certain additives), simplifying logistics and lowering freight costs.
From a supply security perspective, sodium sulfite benefits from a more mature and diversified global production base. Chinese manufacturers like Hailei have robust capacity, ensuring stable quarterly pricing and reliable container lead times. For high-volume consumers such as power plants or pulp mills, the consistent quality and cost stability of sodium sulfite make it a safer long-term procurement choice.
Weifang Hailei Fine Chemical Co., Ltd. has been a trusted partner for industrial chemical buyers worldwide for over a decade. Our sodium sulfite is produced in modern ISO-certified facilities to consistent purity levels, with regular third-party testing. We offer flexible packaging options—25 kg woven bags, 1,000 kg supersacks, or custom requests—and assist with all export documentation, including Certificate of Analysis (CoA) and MSDS in multiple languages.
Our technical support team can help you optimize dosage, compare material cost per unit of active reducing power, and even arrange trial samples for your plant trials. Visit our dedicated sodium sulfite page for full product details and a downloadable preliminary specification.
Whether you are finalizing your boiler water treatment program, scaling up a textile desizing line, or evaluating alternative suppliers, the right choice between sodium hydrosulfite and sodium sulfite begins with accurate technical data and reliable supplier support. Hailei Chemical is ready to deliver the high-quality sodium sulfite you need, on time and on spec.
Request a competitive quote today or speak with one of our industrial chemical specialists for personalized assistance in selecting the optimal reducing agent for your process.
When purchasing industrial chemicals, precision is everything. For boiler water treatment specialists and power plant chemical buyers, the sodium sulfite molecular weight is not just a number on a data sheet—it is the foundation of accurate dosing, cost control, and system protection. Sodium sulfite (Na₂SO₃) acts as a highly effective oxygen scavenger, but its performance hinges on understanding stoichiometric ratios that begin with its molecular weight. Whether you are comparing it to sodium metabisulfite vs sodium sulfite or clarifying a search for what is sodium sulfate potas, the data behind the formula matters when you are deciding where to buy sodium sulfite in bulk. In this article, we examine how molecular weight influences real-world procurement and application decisions.
Sodium sulfite is an inorganic sodium salt of sulfurous acid, represented by the chemical formula Na₂SO₃. It appears as a white crystalline powder that is highly soluble in water, with a slightly sulfurous odor. The compound is available in two primary forms: anhydrous sodium sulfite (Na₂SO₃) and sodium sulfite heptahydrate (Na₂SO₃·7H₂O). Each has a distinct molecular weight due to the water of crystallization.
The anhydrous form is the commercial standard for most industrial applications because it offers higher active content per unit mass. For procurement, knowing the correct molecular weight is critical when calculating the amount of active oxygen-scavenging substance you receive per shipment, especially if you are comparing prices between suppliers who may provide different hydrates.
In boiler water treatment, sodium sulfite functions as an oxygen scavenger through a direct chemical reaction with dissolved oxygen:
2Na₂SO₃ + O₂ → 2Na₂SO₄
From this stoichiometry, one mole of oxygen (O₂, molecular weight 32.00 g/mol) reacts with two moles of sodium sulfite. Therefore, to remove 1 g of dissolved oxygen, you need theoretically 7.88 g of anhydrous sodium sulfite (since 2 × 126.04 / 32.00 = 7.875). However, industrial-grade sodium sulfite typically has a purity of 96–98%, which must be factored into the dosage formula.
Dosing without considering molecular weight leads to either underfeeding—risking pitting corrosion in boiler tubes—or overfeeding, wasting money and increasing dissolved solids that require more blowdown. Every procurement professional dealing with sodium sulfite molecular weight data can translate a specification sheet into reliable operational efficiency.
Consider a 100 MW power plant that must treat 500 m³ of feedwater per hour, with an average dissolved oxygen content of 5 mg/L. The hourly oxygen load equals 2,500 g. The theoretical minimum sodium sulfite requirement is 2,500 × 7.875 = 19,687.5 g, or nearly 20 kg per hour. With a product of 97% purity, the actual amount needed becomes approximately 20.3 kg/h. Over a year, even a 5% error in molecular-weight-based calculation can accumulate into tens of thousands of dollars in chemical waste or damage repair.
Explore our sodium sulfite specifications and purity grades for boiler water applications.
Many buyers confuse sodium metabisulfite (Na₂S₂O₅) with sodium sulfite, especially when sourcing an affordable oxygen scavenger. The search query sodium metabisulfite vs sodium sulfite reflects a real evaluation many engineers perform. The molecular weight difference is crucial here because metabisulfite reacts in water to form sulfite:
Na₂S₂O₅ + H₂O → 2NaHSO₃ (which further dissociates to provide sulfite ions)
The effective sulfite (SO₃²⁻) molecular weight per gram of product is not directly comparable. Anhydrous sodium sulfite has a molecular weight of 126.04 g/mol and provides one mole of sulfite. Sodium metabisulfite (molecular weight 190.11 g/mol) yields two moles of bisulfite, but the effective scavenging capacity is not simply double. Empirical equivalence factors are used: approximately 1.5 parts of metabisulfite are needed to replace 1 part of sulfite by weight, all else being equal. For accurate boiler treatment, stick to sulfite products with defined molecular weight parameters—this avoids the variability of the metastable metabisulfite solution.
Understanding sodium metabisulfite vs sodium sulfite from a molecular weight perspective helps procurement teams avoid the pitfall of purchasing a cheaper product that delivers less active sulfite per ton.
A common point of confusion arises between sodium sulphate (Na₂SO₄) and sodium sulfite. The spellings are similar, and both appear in industrial water chemistry. However, the sodium sulphate vs sodium sulfite distinction is fundamental: sulfate is the oxidized end-product after sulfite has done its job, and it has no oxygen-scavenging capability. Sodium sulfate molecular weight is 142.04 g/mol, compared to 126.04 g/mol for sulfite. When analyzing boiler water chemistry, the presence of sulfate indicates that sulfite has successfully reacted with oxygen. Buyers who mistakenly purchase sodium sulfate instead of sodium sulfite lose all scavenging protection, so verifying the CAS number (7757-83-7 for sulfite vs. 7757-82-6 for sulfate) and molecular weight on a certificate of analysis is essential.
Some users enter the phrase what is sodium sulfate potas into search engines. This appears to be a typographical blending of sodium sulfate and potassium or potash. There is no standard chemical called “sodium sulfate potas.” It likely originates from a mis-typed query asking about sodium sulfate in combination with potassium salts. Potash refers to potassium carbonate, and sodium sulfate is a distinct compound. If you arrived here looking for sodium sulfate’s role in potash processes, it is sometimes used as a filler or in mineral processing, but it has no relevance to oxygen scavenging. For boiler water treatment, sodium sulfite is the correct choice, and its molecular weight of 126.04 g/mol ensures you are ordering the right chemistry.
When you are ready to where to buy sodium sulfite, the specification sheet should clearly state the molecular weight and purity. Industrial grades range from 96% to 98% Na₂SO₃ content, with the balance being mainly sodium sulfate and residual water. The effective “available sulfite” molecular weight per gram of delivered product can be calculated as:
Effective weight fraction = Purity × (Molar mass of sulfite ion / Molar mass of Na₂SO₃)
For a 97% pure product, not all that mass is active scavenger because some impurities exist. Still, the molecular weight you use for stoichiometry should be based on the certified assay. Reputable suppliers, like Hailei Chemical, provide detailed certificates of analysis with assay, molecular weight, and hydrate form clearly indicated. This transparency allows you to accurately compare quotes and ensure the product meets ASME or VGB guidelines for boiler water chemistry.
Download a sample COA and see typical sodium sulfite purity levels from Hailei Chemical.
Finding a reliable source for industrial sodium sulfite involves more than a quick internet search. Use the following criteria when shortlisting suppliers:
Hailei Fine Chemical, based in Weifang, China, is a leading exporter of sodium sulfite anhydrous. Our product consistently delivers 96–98% purity with a molecular weight of 126.04 g/mol, and we support our customers with pre-shipment samples, documentation for customs, and flexible logistics solutions. Whether your interest lies in the sodium sulfite molecular weight for precise dosing or in comparing sodium metabisulfite vs sodium sulfite, our technical team can help you make an informed decision.
From boiler water oxygen scavenging to pulp processing and textile bleaching, sodium sulfite’s performance starts with its fundamental chemical identity. The molecular weight of 126.04 g/mol for the anhydrous form is the key that unlocks accurate usage rates, cost comparisons, and quality verification. Avoiding confusion between sodium sulphate vs sodium sulfite, or understanding the obscure query what is sodium sulfate potas, all reinforce how critical it is to order the right chemical. When you know where to buy sodium sulfite and what specifications to demand, you gain control over your process and your budget.
Get in touch with Hailei Chemical today for a competitive quote on bulk sodium sulfite. Let us show you how consistent quality and clear specification data support your long-term boiler reliability.
Request Your Sodium Sulfite Quote Now
For procurement managers and chemical engineers, understanding a detailed sodium sulfite specification is the foundation of safe, efficient, and cost-effective operations. Whether you are sourcing oxygen scavengers for high-pressure boiler systems or bleaching neutralizers for textile finishing, the technical data sheet dictates performance, storage stability, and compliance. A clear sodium sulfite specification reduces supply chain risk, prevents unplanned downtime, and ensures you receive a product that exactly matches your process requirements. This comprehensive guide deciphers every critical parameter, compares grades, and explains how to evaluate supplier documentation with confidence.
A generic purchase of “sodium sulfite” is never sufficient for demanding industrial environments. The difference between a 96% purity anhydrous powder and a 60% heptahydrate crystalline material affects dosing rates, corrosion control, and even regulatory compliance. In boiler water treatment, a poorly specified product may leave residual oxygen that accelerates pitting in steam circuits. In pulp processing, off-spec sulfite can alter pulp brightness and increase downstream bleaching costs. That is why leading power plants, pulp mills, and textile houses place the sodium sulfite specification at the core of their procurement framework—it is the measurable promise of quality before the first kilogram is shipped.
A typical certificate of analysis for sodium sulfite includes several key indicators. Understanding each one ensures you compare like-for-like across suppliers and avoid hidden cost pitfalls.
The sodium sulfite structure (Na₂SO₃) is a white, crystalline or powdered salt composed of two sodium cations and one sulfite anion. The sulfite ion (SO₃²⁻) is the active reducing agent that consumes dissolved oxygen, neutralizes residual peroxides, and functions as a preservative. Specifications always state the assay—the actual percentage of Na₂SO₃ in the material. For industrial applications, a purity of 96–98% for anhydrous grade is the benchmark, while heptahydrate (Na₂SO₃·7H₂O) typically assays around 60% Na₂SO₃ content, with the balance being water of crystallization. A lower assay forces you to handle and pay for more inert material, increasing freight costs and storage volume.
The primary sodium sulfite specification is the Na₂SO₃ content. For boiler water treatment, a minimum 96% purity ensures efficient oxygen removal with predictable dosing. Photographic-grade sodium sulfite often demands ≥98% purity to avoid streaks or fog on imaging materials. When comparing offers, always ask whether the purity is expressed on an “as is” or “dry basis”—this can reveal hidden moisture that dilutes the active ingredient.
Sodium sulfite is supplied as a white crystalline powder or granular solid. The specification will describe it as “white free-flowing powder” or “colorless crystals.” Any off-white or yellowish tint indicates oxidation to sodium sulfate or the presence of iron, which can stain pulp and textiles. Particle size distribution matters too: fine powders dissolve faster in cold water makeup for boilers, while granular forms minimize dusting and improve handling safety in large-scale batching operations.
A 1% or 5% aqueous solution of sodium sulfite is alkaline, typically with a pH of 9.0–10.5. This alkaline nature helps neutralize acidic components in boiler water but must be factored into overall water chemistry. A specification sheet that lists pH gives you an early indication of the product’s consistency and possible contamination by free alkali or sulfate.
For potable water or food-contact applications, trace heavy metals like lead, arsenic, and iron are tightly controlled. Even in industrial steam generation, iron content above 20 ppm can foul heat transfer surfaces or catalyze oxygen corrosion. A robust sodium sulfite specification will quantify Fe, Pb, As, and chloride levels, allowing you to assess long-term deposit risks. High-purity grades often guarantee Fe ≤ 0.002% and chloride ≤ 0.01%.
Undissolved solids can clog metering pumps and spray nozzles. Specifications may include “water insoluble matter” typically ≤0.05% for premium grades. If your application requires clear, sediment-free solutions—such as in photographic developers or textile bleaching baths—this figure becomes non-negotiable.
Sodium sulfite is traded predominantly in two forms, and choosing the wrong one can double your shipping costs or sabotage your process.
When you review a supplier’s data sheet, confirm which form is being offered and whether the assay accounts for hydration water. Many procurement errors stem from mistaking a heptahydrate price for an anhydrous equivalent. Always normalise delivered cost to the Na₂SO₃ basis for accurate comparison.
In powerhouse chemistry, dissolved oxygen is enemy number one. A precise sodium sulfite specification is essential because the oxygen-scavenging reaction is stoichiometric: 7.88 ppm of Na₂SO₃ is required to remove 1 ppm of dissolved O₂. If your product assays only 90% purity, you must dose 9% more chemical, increasing treatment costs and adding unnecessary sodium sulfate to the boiler water—raising blowdown frequency and fuel losses. A high-purity product like high-purity sodium sulfite for boiler water oxygen scavenging from Hailei Chemical enables slim and accurate dosing, minimizes sulfite sludge, and extends boiler tube life.
Additionally, boiler-grade sodium sulfite specifications should include a rapid dissolution rate. At feedwater temperatures of 60–80°C, full solubility must be reached within minutes to prevent undissolved particles from depositing in economizers. Look for “solubility: >20 g/100 mL water at 20°C” on the data sheet as a baseline.
Global buyers rely on standardized benchmarks to qualify suppliers. Common references in a sodium sulfite specification include:
Suppliers who can provide an analysis certificate aligned with these standards demonstrate robust quality management systems. Request ISO 9001 documentation and, for power generation buyers, third-party lab verifications that confirm compliance with pressure part protection guidelines.
When you ask “where can i buy sodium sulfite” that truly meets your spec, the answer often lies in the granularity of the supplier’s data. A trustworthy sodium sulfite supplier will offer:
At Hailei Chemical, our technical sales team helps you interpret every line of the sodium sulfite for industrial applications specification against your operational KPIs. This partnership approach prevents over-specifying (and overpaying) or under-specifying and risking process failure.
While heavy industries dominate procurement volumes, some buyers wonder: what is sodium sulfite in shampoo? In cosmetic formulations, sodium sulfite acts as a reducing agent, most notably in hair straightening treatments where it breaks disulfide bonds in keratin. For these personal-care uses, the specification is ultra-stringent: assay ≥98%, mercury <1 ppm, and microbial limits to ensure consumer safety. Although this market is niche compared to boiler treatment, the same analytical rigour applies. Cosmetics manufacturers often order small quantities of the highest purity grades, demonstrating that the sodium sulfite specification always dictates the application’s success.
It includes main content (Na₂SO₃ purity), appearance, pH, heavy metals (Fe, Pb, As), chloride, water insolubles, and for heptahydrate, water of crystallization. Some sheets also list sulfate content, particle size, and bulk density.
Request a pre-shipment sample for third-party lab analysis. Standard analytical methods include iodometric titration for sulfite content and ICP-OES for trace metals. Reputable suppliers will gladly provide a certificate of analysis from an accredited laboratory.
Not necessarily. Anhydrous offers higher activity and lower freight cost per active kilogram, making it the default for boiler and pulp users. Heptahydrate can be advantageous in cold regions where it is less prone to caking, and where the water addition is not detrimental to the process.
Direct-source manufacturers like Hailei Chemical offer sodium sulfite that complies with GB/T 9005, ACS, and other international standards. Consolidating supply with a manufacturer who exports regularly to your region ensures consistent quality and container-load economics.
Weifang Hailei Fine Chemical Co., Ltd. provides a fully transparent sodium sulfite specification with every shipment. Our anhydrous sodium sulfite is produced under stringent quality controls, yielding a 96–98% pure white powder engineered for the most demanding boiler water, pulp bleaching, and textile processing operations. We export to over 30 countries, offering flexible packaging, reliable logistics, and the technical support that large-scale industrial buyers require.
When your process depends on a precise chemical input, do not gamble with ambiguous data sheets. For a tailored quotation and to discuss your specific requirement parameters, visit our product page or reach out directly. Our specialists will help you navigate every aspect of the sodium sulfite specification to secure optimal performance and cost-efficiency.
Request a quote for high-purity sodium sulfite today and experience the difference a true specification partner can make.
When sourcing industrial reducing agents, procurement professionals often face the decision: sodium hydrosulfite vs sodium sulfite. Both chemicals serve as powerful reducing agents, but their distinct chemistries, handling requirements, and application profiles make each suited to very different processes. Choosing the wrong product can lead to efficiency losses, safety incidents, and inflated operating costs. In this comprehensive buyer’s guide, we break down the key differences, examine technical specifications, review safety data sheets (SDS), and provide practical procurement insights to help you make an informed choice.
At the molecular level, sodium hydrosulfite (also called sodium dithionite, Na₂S₂O₄) and sodium sulfite (Na₂SO₃) differ fundamentally. Sodium hydrosulfite contains sulfur in an oxidation state of +3, while sulfite has sulfur at +4. This difference gives hydrosulfite a much stronger reducing capability, but also makes it more reactive, unstable, and hazardous. Sodium sulfite is a milder, more stable reducing agent that is easier to handle and store.
Key chemical properties at a glance:
These chemical profiles directly impact how each product is used in industrial settings. Hydrosulfite’s aggressive reactivity is essential for rapid bleaching operations, while sulfite’s stability and controlled release of sulfite ions make it ideal for long-duration processes like boiler water deoxygenation.
Sodium hydrosulfite is the reducing agent of choice when high reduction power and speed are critical. It is widely used in:
Its ability to reduce dyes and colored impurities rapidly makes it indispensable in these color-sensitive sectors. However, the instability of hydrosulfite demands stringent storage (cool, dry, airtight conditions) and short shelf life.
Sodium sulfite’s moderate and stable reducing action finds a different set of heavy industrial uses:
A procurement manager for a power plant will find sodium sulfite essential for corrosion control, while a textile finishing plant manager may need both chemicals for different steps in their workflow. Understanding these specific roles is critical when comparing sodium hydrosulfite vs sodium sulfite.
When procuring sodium sulfite, technical buyers must verify that the offered grade meets their process tolerances. Typical industrial grade sodium sulfite specifications from a reliable supplier like Weifang Hailei Fine Chemical Co., Ltd. include:
| Parameter | Specification (Typical) |
|---|---|
| Purity (Na₂SO₃) | ≥ 96.0% (anhydrous), ≥ 98.0% for certain grades |
| Iron (Fe) | ≤ 0.005% |
| Water Insoluble Matter | ≤ 0.03% |
| pH (5% aqueous solution) | 9.0 – 10.5 |
| Heavy Metals (as Pb) | ≤ 0.002% |
| Appearance | White to slightly yellowish crystalline powder or granules |
Buyers should pay special attention to iron content and water insolubles, as these can foul boiler internals or discolor pulps. Sodium sulfite is available in anhydrous (Na₂SO₃) and heptahydrate (Na₂SO₃·7H₂O) forms, with the anhydrous grade offering higher active content and lower shipping weights—a key logistics consideration. For detailed technical data, download the full specification sheet on our sodium sulfite product page.
Understanding how sodium sulfite in water behaves is essential for safe and effective use. Sodium sulfite is highly soluble: about 28 grams dissolve in 100 mL of water at 20°C, forming a clear, mildly alkaline solution (pH ~9.5 for a 5% solution). The dissolution process is slightly endothermic, causing a minor temperature drop.
In boiler water treatment, the sulfite ion (SO₃²⁻) reacts with dissolved oxygen to form sulfate (SO₄²⁻), a stable and non-corrosive byproduct. The reaction is fast at elevated temperatures (>80°C), making sulfite an excellent oxygen scavenger. A typical maintenance dosage is 30-60 mg/L of sodium sulfite, depending on feedwater oxygen levels and system metallurgy. Overdosing can increase boiler water solids, so precise control is recommended.
When preparing solutions, always add sodium sulfite to water slowly with agitation, wearing appropriate PPE. Avoid direct contact with acids, as this can release toxic sulfur dioxide gas. For large-volume users, Hailei Chemical can provide soluble bag or pre-dissolved delivery advice to simplify handling.
Industrial safety managers rely on the Safety Data Sheet (SDS) to assess hazards and establish safe handling protocols. The sodium sulfite SDS classifies the product as a skin and eye irritant, as well as a respiratory irritant. Typical GHS hazard statements include H315 (Causes skin irritation), H319 (Causes serious eye irritation), and H335 (May cause respiratory irritation). The corresponding GHS pictogram is the exclamation mark.
In contrast, sodium hydrosulfite carries more severe hazards: it is classified as a self-heating substance (H251), can ignite spontaneously if exposed to moist air, and releases toxic sulfur dioxide fumes upon decomposition. Its SDS will show both the flame (GHS02) and exclamation mark (GHS07) pictograms, along with stricter storage and handling requirements.
Key safety recommendations for sodium sulfite:
The SDS should always be consulted before use. Hailei Chemical provides compliant SDS documentation with every shipment, ensuring full regulatory transparency for importers and end-users.
While this guide focuses on industrial technical grades, the keyword sodium sulphite in food frequently appears in procurement conversations. Sodium sulfite is recognized as food additive E221 and functions as a preservative and antioxidant in certain foods such as dried fruits, fruit juices, and wine making. It prevents browning and microbial growth. However, food-grade sodium sulfite must meet strict purity criteria (typically ≥ 98.5%, heavy metals < 5 ppm, etc.) and is supplied under a separate certification program.
Hailei Chemical’s standard sodium sulfite is a technical grade product intended for industrial applications like water treatment, pulp, and textiles. If your facility requires food-grade material, please contact our technical team to discuss feasibility and custom specification options. We always advise buyers to clearly state intended use to ensure you receive the appropriate grade, avoiding costly rejections at customs.
When evaluating sodium hydrosulfite vs sodium sulfite, total cost of ownership often tips the scale toward sulfite for many applications. Sodium hydrosulfite is typically 2–3 times more expensive per ton, has tighter storage constraints (often requiring air-conditioned warehousing), and a shorter shelf life (6-12 months) compared to sodium sulfite’s 2-year shelf life when stored properly. Shipping also differs: hydrosulfite is classified as a hazardous material (Class 4.2 self-heating substance) under international transport regulations, triggering stricter packaging and handling surcharges. Sodium sulfite is generally classed as non-dangerous for transport (unless mixed with certain additives), simplifying logistics and lowering freight costs.
From a supply security perspective, sodium sulfite benefits from a more mature and diversified global production base. Chinese manufacturers like Hailei have robust capacity, ensuring stable quarterly pricing and reliable container lead times. For high-volume consumers such as power plants or pulp mills, the consistent quality and cost stability of sodium sulfite make it a safer long-term procurement choice.
Weifang Hailei Fine Chemical Co., Ltd. has been a trusted partner for industrial chemical buyers worldwide for over a decade. Our sodium sulfite is produced in modern ISO-certified facilities to consistent purity levels, with regular third-party testing. We offer flexible packaging options—25 kg woven bags, 1,000 kg supersacks, or custom requests—and assist with all export documentation, including Certificate of Analysis (CoA) and MSDS in multiple languages.
Our technical support team can help you optimize dosage, compare material cost per unit of active reducing power, and even arrange trial samples for your plant trials. Visit our dedicated sodium sulfite page for full product details and a downloadable preliminary specification.
Whether you are finalizing your boiler water treatment program, scaling up a textile desizing line, or evaluating alternative suppliers, the right choice between sodium hydrosulfite and sodium sulfite begins with accurate technical data and reliable supplier support. Hailei Chemical is ready to deliver the high-quality sodium sulfite you need, on time and on spec.
Request a competitive quote today or speak with one of our industrial chemical specialists for personalized assistance in selecting the optimal reducing agent for your process.
When purchasing industrial chemicals, precision is everything. For boiler water treatment specialists and power plant chemical buyers, the sodium sulfite molecular weight is not just a number on a data sheet—it is the foundation of accurate dosing, cost control, and system protection. Sodium sulfite (Na₂SO₃) acts as a highly effective oxygen scavenger, but its performance hinges on understanding stoichiometric ratios that begin with its molecular weight. Whether you are comparing it to sodium metabisulfite vs sodium sulfite or clarifying a search for what is sodium sulfate potas, the data behind the formula matters when you are deciding where to buy sodium sulfite in bulk. In this article, we examine how molecular weight influences real-world procurement and application decisions.
Sodium sulfite is an inorganic sodium salt of sulfurous acid, represented by the chemical formula Na₂SO₃. It appears as a white crystalline powder that is highly soluble in water, with a slightly sulfurous odor. The compound is available in two primary forms: anhydrous sodium sulfite (Na₂SO₃) and sodium sulfite heptahydrate (Na₂SO₃·7H₂O). Each has a distinct molecular weight due to the water of crystallization.
The anhydrous form is the commercial standard for most industrial applications because it offers higher active content per unit mass. For procurement, knowing the correct molecular weight is critical when calculating the amount of active oxygen-scavenging substance you receive per shipment, especially if you are comparing prices between suppliers who may provide different hydrates.
In boiler water treatment, sodium sulfite functions as an oxygen scavenger through a direct chemical reaction with dissolved oxygen:
2Na₂SO₃ + O₂ → 2Na₂SO₄
From this stoichiometry, one mole of oxygen (O₂, molecular weight 32.00 g/mol) reacts with two moles of sodium sulfite. Therefore, to remove 1 g of dissolved oxygen, you need theoretically 7.88 g of anhydrous sodium sulfite (since 2 × 126.04 / 32.00 = 7.875). However, industrial-grade sodium sulfite typically has a purity of 96–98%, which must be factored into the dosage formula.
Dosing without considering molecular weight leads to either underfeeding—risking pitting corrosion in boiler tubes—or overfeeding, wasting money and increasing dissolved solids that require more blowdown. Every procurement professional dealing with sodium sulfite molecular weight data can translate a specification sheet into reliable operational efficiency.
Consider a 100 MW power plant that must treat 500 m³ of feedwater per hour, with an average dissolved oxygen content of 5 mg/L. The hourly oxygen load equals 2,500 g. The theoretical minimum sodium sulfite requirement is 2,500 × 7.875 = 19,687.5 g, or nearly 20 kg per hour. With a product of 97% purity, the actual amount needed becomes approximately 20.3 kg/h. Over a year, even a 5% error in molecular-weight-based calculation can accumulate into tens of thousands of dollars in chemical waste or damage repair.
Explore our sodium sulfite specifications and purity grades for boiler water applications.
Many buyers confuse sodium metabisulfite (Na₂S₂O₅) with sodium sulfite, especially when sourcing an affordable oxygen scavenger. The search query sodium metabisulfite vs sodium sulfite reflects a real evaluation many engineers perform. The molecular weight difference is crucial here because metabisulfite reacts in water to form sulfite:
Na₂S₂O₅ + H₂O → 2NaHSO₃ (which further dissociates to provide sulfite ions)
The effective sulfite (SO₃²⁻) molecular weight per gram of product is not directly comparable. Anhydrous sodium sulfite has a molecular weight of 126.04 g/mol and provides one mole of sulfite. Sodium metabisulfite (molecular weight 190.11 g/mol) yields two moles of bisulfite, but the effective scavenging capacity is not simply double. Empirical equivalence factors are used: approximately 1.5 parts of metabisulfite are needed to replace 1 part of sulfite by weight, all else being equal. For accurate boiler treatment, stick to sulfite products with defined molecular weight parameters—this avoids the variability of the metastable metabisulfite solution.
Understanding sodium metabisulfite vs sodium sulfite from a molecular weight perspective helps procurement teams avoid the pitfall of purchasing a cheaper product that delivers less active sulfite per ton.
A common point of confusion arises between sodium sulphate (Na₂SO₄) and sodium sulfite. The spellings are similar, and both appear in industrial water chemistry. However, the sodium sulphate vs sodium sulfite distinction is fundamental: sulfate is the oxidized end-product after sulfite has done its job, and it has no oxygen-scavenging capability. Sodium sulfate molecular weight is 142.04 g/mol, compared to 126.04 g/mol for sulfite. When analyzing boiler water chemistry, the presence of sulfate indicates that sulfite has successfully reacted with oxygen. Buyers who mistakenly purchase sodium sulfate instead of sodium sulfite lose all scavenging protection, so verifying the CAS number (7757-83-7 for sulfite vs. 7757-82-6 for sulfate) and molecular weight on a certificate of analysis is essential.
Some users enter the phrase what is sodium sulfate potas into search engines. This appears to be a typographical blending of sodium sulfate and potassium or potash. There is no standard chemical called “sodium sulfate potas.” It likely originates from a mis-typed query asking about sodium sulfate in combination with potassium salts. Potash refers to potassium carbonate, and sodium sulfate is a distinct compound. If you arrived here looking for sodium sulfate’s role in potash processes, it is sometimes used as a filler or in mineral processing, but it has no relevance to oxygen scavenging. For boiler water treatment, sodium sulfite is the correct choice, and its molecular weight of 126.04 g/mol ensures you are ordering the right chemistry.
When you are ready to where to buy sodium sulfite, the specification sheet should clearly state the molecular weight and purity. Industrial grades range from 96% to 98% Na₂SO₃ content, with the balance being mainly sodium sulfate and residual water. The effective “available sulfite” molecular weight per gram of delivered product can be calculated as:
Effective weight fraction = Purity × (Molar mass of sulfite ion / Molar mass of Na₂SO₃)
For a 97% pure product, not all that mass is active scavenger because some impurities exist. Still, the molecular weight you use for stoichiometry should be based on the certified assay. Reputable suppliers, like Hailei Chemical, provide detailed certificates of analysis with assay, molecular weight, and hydrate form clearly indicated. This transparency allows you to accurately compare quotes and ensure the product meets ASME or VGB guidelines for boiler water chemistry.
Download a sample COA and see typical sodium sulfite purity levels from Hailei Chemical.
Finding a reliable source for industrial sodium sulfite involves more than a quick internet search. Use the following criteria when shortlisting suppliers:
Hailei Fine Chemical, based in Weifang, China, is a leading exporter of sodium sulfite anhydrous. Our product consistently delivers 96–98% purity with a molecular weight of 126.04 g/mol, and we support our customers with pre-shipment samples, documentation for customs, and flexible logistics solutions. Whether your interest lies in the sodium sulfite molecular weight for precise dosing or in comparing sodium metabisulfite vs sodium sulfite, our technical team can help you make an informed decision.
From boiler water oxygen scavenging to pulp processing and textile bleaching, sodium sulfite’s performance starts with its fundamental chemical identity. The molecular weight of 126.04 g/mol for the anhydrous form is the key that unlocks accurate usage rates, cost comparisons, and quality verification. Avoiding confusion between sodium sulphate vs sodium sulfite, or understanding the obscure query what is sodium sulfate potas, all reinforce how critical it is to order the right chemical. When you know where to buy sodium sulfite and what specifications to demand, you gain control over your process and your budget.
Get in touch with Hailei Chemical today for a competitive quote on bulk sodium sulfite. Let us show you how consistent quality and clear specification data support your long-term boiler reliability.
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For procurement managers and chemical engineers, understanding a detailed sodium sulfite specification is the foundation of safe, efficient, and cost-effective operations. Whether you are sourcing oxygen scavengers for high-pressure boiler systems or bleaching neutralizers for textile finishing, the technical data sheet dictates performance, storage stability, and compliance. A clear sodium sulfite specification reduces supply chain risk, prevents unplanned downtime, and ensures you receive a product that exactly matches your process requirements. This comprehensive guide deciphers every critical parameter, compares grades, and explains how to evaluate supplier documentation with confidence.
A generic purchase of “sodium sulfite” is never sufficient for demanding industrial environments. The difference between a 96% purity anhydrous powder and a 60% heptahydrate crystalline material affects dosing rates, corrosion control, and even regulatory compliance. In boiler water treatment, a poorly specified product may leave residual oxygen that accelerates pitting in steam circuits. In pulp processing, off-spec sulfite can alter pulp brightness and increase downstream bleaching costs. That is why leading power plants, pulp mills, and textile houses place the sodium sulfite specification at the core of their procurement framework—it is the measurable promise of quality before the first kilogram is shipped.
A typical certificate of analysis for sodium sulfite includes several key indicators. Understanding each one ensures you compare like-for-like across suppliers and avoid hidden cost pitfalls.
The sodium sulfite structure (Na₂SO₃) is a white, crystalline or powdered salt composed of two sodium cations and one sulfite anion. The sulfite ion (SO₃²⁻) is the active reducing agent that consumes dissolved oxygen, neutralizes residual peroxides, and functions as a preservative. Specifications always state the assay—the actual percentage of Na₂SO₃ in the material. For industrial applications, a purity of 96–98% for anhydrous grade is the benchmark, while heptahydrate (Na₂SO₃·7H₂O) typically assays around 60% Na₂SO₃ content, with the balance being water of crystallization. A lower assay forces you to handle and pay for more inert material, increasing freight costs and storage volume.
The primary sodium sulfite specification is the Na₂SO₃ content. For boiler water treatment, a minimum 96% purity ensures efficient oxygen removal with predictable dosing. Photographic-grade sodium sulfite often demands ≥98% purity to avoid streaks or fog on imaging materials. When comparing offers, always ask whether the purity is expressed on an “as is” or “dry basis”—this can reveal hidden moisture that dilutes the active ingredient.
Sodium sulfite is supplied as a white crystalline powder or granular solid. The specification will describe it as “white free-flowing powder” or “colorless crystals.” Any off-white or yellowish tint indicates oxidation to sodium sulfate or the presence of iron, which can stain pulp and textiles. Particle size distribution matters too: fine powders dissolve faster in cold water makeup for boilers, while granular forms minimize dusting and improve handling safety in large-scale batching operations.
A 1% or 5% aqueous solution of sodium sulfite is alkaline, typically with a pH of 9.0–10.5. This alkaline nature helps neutralize acidic components in boiler water but must be factored into overall water chemistry. A specification sheet that lists pH gives you an early indication of the product’s consistency and possible contamination by free alkali or sulfate.
For potable water or food-contact applications, trace heavy metals like lead, arsenic, and iron are tightly controlled. Even in industrial steam generation, iron content above 20 ppm can foul heat transfer surfaces or catalyze oxygen corrosion. A robust sodium sulfite specification will quantify Fe, Pb, As, and chloride levels, allowing you to assess long-term deposit risks. High-purity grades often guarantee Fe ≤ 0.002% and chloride ≤ 0.01%.
Undissolved solids can clog metering pumps and spray nozzles. Specifications may include “water insoluble matter” typically ≤0.05% for premium grades. If your application requires clear, sediment-free solutions—such as in photographic developers or textile bleaching baths—this figure becomes non-negotiable.
Sodium sulfite is traded predominantly in two forms, and choosing the wrong one can double your shipping costs or sabotage your process.
When you review a supplier’s data sheet, confirm which form is being offered and whether the assay accounts for hydration water. Many procurement errors stem from mistaking a heptahydrate price for an anhydrous equivalent. Always normalise delivered cost to the Na₂SO₃ basis for accurate comparison.
In powerhouse chemistry, dissolved oxygen is enemy number one. A precise sodium sulfite specification is essential because the oxygen-scavenging reaction is stoichiometric: 7.88 ppm of Na₂SO₃ is required to remove 1 ppm of dissolved O₂. If your product assays only 90% purity, you must dose 9% more chemical, increasing treatment costs and adding unnecessary sodium sulfate to the boiler water—raising blowdown frequency and fuel losses. A high-purity product like high-purity sodium sulfite for boiler water oxygen scavenging from Hailei Chemical enables slim and accurate dosing, minimizes sulfite sludge, and extends boiler tube life.
Additionally, boiler-grade sodium sulfite specifications should include a rapid dissolution rate. At feedwater temperatures of 60–80°C, full solubility must be reached within minutes to prevent undissolved particles from depositing in economizers. Look for “solubility: >20 g/100 mL water at 20°C” on the data sheet as a baseline.
Global buyers rely on standardized benchmarks to qualify suppliers. Common references in a sodium sulfite specification include:
Suppliers who can provide an analysis certificate aligned with these standards demonstrate robust quality management systems. Request ISO 9001 documentation and, for power generation buyers, third-party lab verifications that confirm compliance with pressure part protection guidelines.
When you ask “where can i buy sodium sulfite” that truly meets your spec, the answer often lies in the granularity of the supplier’s data. A trustworthy sodium sulfite supplier will offer:
At Hailei Chemical, our technical sales team helps you interpret every line of the sodium sulfite for industrial applications specification against your operational KPIs. This partnership approach prevents over-specifying (and overpaying) or under-specifying and risking process failure.
While heavy industries dominate procurement volumes, some buyers wonder: what is sodium sulfite in shampoo? In cosmetic formulations, sodium sulfite acts as a reducing agent, most notably in hair straightening treatments where it breaks disulfide bonds in keratin. For these personal-care uses, the specification is ultra-stringent: assay ≥98%, mercury <1 ppm, and microbial limits to ensure consumer safety. Although this market is niche compared to boiler treatment, the same analytical rigour applies. Cosmetics manufacturers often order small quantities of the highest purity grades, demonstrating that the sodium sulfite specification always dictates the application’s success.
It includes main content (Na₂SO₃ purity), appearance, pH, heavy metals (Fe, Pb, As), chloride, water insolubles, and for heptahydrate, water of crystallization. Some sheets also list sulfate content, particle size, and bulk density.
Request a pre-shipment sample for third-party lab analysis. Standard analytical methods include iodometric titration for sulfite content and ICP-OES for trace metals. Reputable suppliers will gladly provide a certificate of analysis from an accredited laboratory.
Not necessarily. Anhydrous offers higher activity and lower freight cost per active kilogram, making it the default for boiler and pulp users. Heptahydrate can be advantageous in cold regions where it is less prone to caking, and where the water addition is not detrimental to the process.
Direct-source manufacturers like Hailei Chemical offer sodium sulfite that complies with GB/T 9005, ACS, and other international standards. Consolidating supply with a manufacturer who exports regularly to your region ensures consistent quality and container-load economics.
Weifang Hailei Fine Chemical Co., Ltd. provides a fully transparent sodium sulfite specification with every shipment. Our anhydrous sodium sulfite is produced under stringent quality controls, yielding a 96–98% pure white powder engineered for the most demanding boiler water, pulp bleaching, and textile processing operations. We export to over 30 countries, offering flexible packaging, reliable logistics, and the technical support that large-scale industrial buyers require.
When your process depends on a precise chemical input, do not gamble with ambiguous data sheets. For a tailored quotation and to discuss your specific requirement parameters, visit our product page or reach out directly. Our specialists will help you navigate every aspect of the sodium sulfite specification to secure optimal performance and cost-efficiency.
Request a quote for high-purity sodium sulfite today and experience the difference a true specification partner can make.