For procurement managers and chemical engineers sourcing bulk reducing agents, a thorough understanding of the properties of sodium metabisulfite is the foundation of successful formulation, safe handling, and cost-effective supply chain management. From water dechlorination at municipal treatment plants to cyanide detoxification in gold mines and sulfite preservation in food processing, this versatile inorganic compound delivers reliable performance only when its chemical and physical characteristics align with end-use requirements.
At Weifang Hailei Fine Chemical Co., Ltd., we supply sodium metabisulfite (Na₂S₂O₅, CAS 7681-57-4) in both food-grade (FCC compliant) and industrial-grade (97–98% purity) to buyers across India, Southeast Asia, Africa, and the Middle East. This guide decodes every property you need to evaluate before issuing a purchase order, helping you avoid caking in storage, insufficient SO₂ release, or regulatory non-compliance.
Understanding what is sodium metabisulfite made from clarifies its inherent properties. Industrially, sodium metabisulfite is produced by saturating a sodium carbonate or sodium hydroxide solution with sulfur dioxide (SO₂). The exothermic reaction first forms sodium bisulfite (NaHSO₃) in solution, which is then carefully dehydrated through cooling and controlled crystallization to yield solid sodium metabisulfite:
2 NaHSO₃(aq) → Na₂S₂O₅(s) + H₂O
The product is a white to yellowish crystalline powder or granular material with a pungent SO₂ odor. Because its synthesis relies on high-purity SO₂ gas and a low-iron process environment, the quality of inputs directly determines the final product’s heavy metal profile and clarity in solution. For food-grade material, additional purification steps ensure compliance with FCC or E223 monographs, making it safe for use as a preservative in dried fruits, wines, and starch syrups.
A technical evaluation begins with the core properties of sodium metabisulfite. These data points influence dissolution rates, dosing precision, and compatibility with other process chemicals.
These parameters are not just laboratory curiosities—they directly affect real-world outcomes. For instance, the acidic pH of a metabisulfite solution makes it ideal for acidifying and preserving high-sugar food systems, while the decomposition temperature dictates safe storage away from heat sources.
Sodium metabisulfite is traded primarily in two purity specifications: industrial grade (typically 97–98% Na₂S₂O₅) and food grade (≥98% plus strict limits on iron, arsenic, and heavy metals). The property differences may seem subtle, but they have outsized impacts in sensitive applications.
Industrial grade (97–98%): Optimized for water treatment, gold mining (cyanide destruction), and pulp & paper bleaching. A lower assay of 97% still supplies more than 65% equivalent SO₂ content, but the 1–2% inert salts or sulfate residues can affect clarity in closed-loop water systems. Buyers should monitor iron content (<0.003% typical), since dissolved iron can catalyze unwanted oxidation or stain pulp.
Food grade (FCC/E223): Must meet purity thresholds for arsenic (≤3 mg/kg), lead (≤2 mg/kg), and selenium. The absence of chloride by-products ensures no off-flavors in wine or dried fruit. At Hailei Chemical, our food-grade sodium metabisulfite is manufactured under rigorous HACCP-guided protocols to guarantee compliance with international food safety standards.
When specifying your purchase, always request a Certificate of Analysis (COA) detailing assay, SO₂ content, pH of 10% solution, iron, heavy metals, and water-insoluble matter. The sodium metabisulfite product page provides typical Hailei COA ranges to simplify your comparison.
Many industrial buyers wonder about the interchangeability of sodium bisulfite and sodium metabisulfite. While both provide SO₂ in solution, their chemical properties lead to different dosing behaviors and storage considerations.
| Property | Sodium Metabisulfite (Na₂S₂O₅) | Sodium Bisulfite (NaHSO₃) |
|---|---|---|
| Physical form | Dry crystalline powder/granules | Often supplied as solution (approx. 40%) or crystalline solid (less stable) |
| SO₂ equivalent | Approx. 65–67% by weight | Approx. 22–24% in commercial solutions; solid bisulfite contains 60–65% but is hygroscopic |
| pH of solution | 4.0–5.5 (10% solution) | 2.5–4.0 (solution), more acidic |
| Stability in storage | Excellent when kept dry; >12 months shelf life | Solution prone to oxidation by air; solid form absorbs moisture rapidly |
| Shipping | Dry bulk; cost-effective long-distance shipping | Solution requires tankers or IBCs; higher freight per active SO₂ |
| Typical applications | Water dechlorination, gold mining, food preservative, pulp bleaching, textile | On-site chlorine neutralization, reducing agent in chemical synthesis, leather tanning |
The choice often boils down to logistics and pH buffering. For intercontinental shipments where freight cost and product stability matter, dry sodium metabisulfite is the preferred form. Upon dissolution in water, it forms sodium bisulfite ions, delivering the same reducing action. However, if your process demands immediate solution without handling dry powder, a pre-made bisulfite solution might be convenient—though it costs more per kilogram of SO₂ delivered. Hailei supplies both dry sodium metabisulfite and can direct you to logistics partners for sodium bisulfite solutions where needed.
Knowing how to use sodium metabisulphite safely and efficiently starts with respecting its reactivity profile. The compound’s core property is its ability to release sulfur dioxide in acidic conditions or when heated, making it a potent oxygen scavenger and antimicrobial agent.
In municipal and industrial water treatment, sodium metabisulfite instantly neutralizes free chlorine and chloramines. The stoichiometric reaction requires 1.34 parts of pure Na₂S₂O₅ per part of chlorine. A typical dosing rate is 2–3 mg/L of a 10% metabisulfite solution per mg/L residual chlorine, adjusted for mixing efficiency. Because the reaction drops pH slightly, systems with low alkalinity may need buffering.
The SO₂/air process (INCO method) uses metabisulfite as the SO₂ source to oxidize cyanides (CN⁻) to cyanate (OCN⁻), catalyzed by copper. The reducing property here must be carefully controlled: a solution pH between 8.5 and 9.5 optimizes cyanide destruction while minimizing off-gassing of HCN. Miners often dose metabisulfite at 2–4 grams per gram of WAD cyanide.
As an E223 additive, sodium metabisulfite inhibits enzymatic and non-enzymatic browning in dried fruits, frozen seafood, and wine. The effective SO₂ concentration for antimicrobial action is 50–400 ppm, depending on the product. Its ability to lower pH helps stabilize ascorbic acid and color. Importantly, residual sulfite must meet local labeling laws—typically <10 ppm SO₂ in final product.
In mechanical pulping, metabisulfite acts as a reducing bleach to brighten lignin-rich pulps without degrading cellulose. The property of preserving fiber strength while increasing brightness by 5–8 ISO points makes it valuable for newsprint and tissue grades. Typical application: 1–3% on oven-dry pulp at pH 5–6.
After chlorine bleaching, fabrics carry residual chlorine that can yellow or weaken fibers. A 0.5–2 g/L sodium metabisulfite bath, based on its rapid dechlorination property, eliminates this risk. The slightly acidic pH helps close fiber cuticles, improving dye uptake in subsequent steps.
For detailed application recipes and custom formulation support, refer to our comprehensive sodium metabisulfite application guide.
Procuring sodium metabisulfite without verifying properties against recognized standards can lead to inconsistent batch performance, rejected shipments, or even plant shutdowns. A rigorous supplier evaluation framework should include the following analytical benchmarks.
Request a batch-specific COA with every shipment. Third-party testing by SGS, Bureau Veritas, or Intertek adds an extra layer of trust. Hailei Chemical routinely arranges pre-shipment inspections against these parameters to ensure that the properties of sodium metabisulfite you order are exactly what you receive.
The shelf life and performance of sodium metabisulfite depend critically on storage conditions. Exposure to moisture and heat degrades its reducing power and turns the powder into a hard, unworkable mass.
Key recommendations:
Understanding these environmental sensitivities allows you to plan inventory turnover and avoid waste, directly protecting your investment in each purchased ton.
India is one of the world’s largest importers of sodium metabisulfite, driven by expansive water treatment programs, a massive gold import sector, and a growing food processing industry. If you are seeking a sodium metabisulfite supplier in India, working directly with a chemical exporter in China can often offer cost advantages of 12–18% compared to local distributors, provided you manage shipping and quality inspection efficiently.
Hailei Chemical serves Indian buyers through Nhava Sheva, Mundra, Chennai, and Kolkata ports. Our typical packaging in 25 kg HDPE bags with inner liner is palletized and shrink-wrapped for tropical climates. We also offer 1000–1250 kg big bags and custom private labeling. For oil & gas or mining tenders, we provide full documentation: COA, MSDS, Certificate of Origin, and fumigation certificates as required by Indian customs (HS Code 28321010).
The same logistics expertise applies to buyers in the Middle East (Jebel Ali, Dammam), Southeast Asia, and Africa. Our in-house team coordinates FCL and LCL shipments, transit times, and demurrage avoidance. By consolidating volumes, we help you optimize landed costs without compromising the high purity and consistent properties of sodium metabisulfite you require.
Since 2005, Weifang Hailei Fine Chemical Co., Ltd. has been manufacturing and exporting sulfur-based chemicals under strict ISO 9001 and industry-specific certifications. Our sodium metabisulfite is produced in a dedicated facility with advanced crystallization controls, ensuring every batch meets the precise physical and chemical properties detailed in this guide. We maintain ready stock in our warehouse, enabling 7–15 day lead times for standard FCL orders.
When you partner with Hailei, you gain:
Don’t leave your procurement to chance. If you need a reliable supply of sodium metabisulfite that matches the property specifications critical to your operation, request a quote today. Visit our sodium metabisulfite product page to download the latest COA, MSDS, and application brochures, and let us customize a shipment that meets your exact volume and grading needs.
For procurement managers and chemical engineers sourcing bulk reducing agents, a thorough understanding of the properties of sodium metabisulfite is the foundation of successful formulation, safe handling, and cost-effective supply chain management. From water dechlorination at municipal treatment plants to cyanide detoxification in gold mines and sulfite preservation in food processing, this versatile inorganic compound delivers reliable performance only when its chemical and physical characteristics align with end-use requirements.
At Weifang Hailei Fine Chemical Co., Ltd., we supply sodium metabisulfite (Na₂S₂O₅, CAS 7681-57-4) in both food-grade (FCC compliant) and industrial-grade (97–98% purity) to buyers across India, Southeast Asia, Africa, and the Middle East. This guide decodes every property you need to evaluate before issuing a purchase order, helping you avoid caking in storage, insufficient SO₂ release, or regulatory non-compliance.
Understanding what is sodium metabisulfite made from clarifies its inherent properties. Industrially, sodium metabisulfite is produced by saturating a sodium carbonate or sodium hydroxide solution with sulfur dioxide (SO₂). The exothermic reaction first forms sodium bisulfite (NaHSO₃) in solution, which is then carefully dehydrated through cooling and controlled crystallization to yield solid sodium metabisulfite:
2 NaHSO₃(aq) → Na₂S₂O₅(s) + H₂O
The product is a white to yellowish crystalline powder or granular material with a pungent SO₂ odor. Because its synthesis relies on high-purity SO₂ gas and a low-iron process environment, the quality of inputs directly determines the final product’s heavy metal profile and clarity in solution. For food-grade material, additional purification steps ensure compliance with FCC or E223 monographs, making it safe for use as a preservative in dried fruits, wines, and starch syrups.
A technical evaluation begins with the core properties of sodium metabisulfite. These data points influence dissolution rates, dosing precision, and compatibility with other process chemicals.
These parameters are not just laboratory curiosities—they directly affect real-world outcomes. For instance, the acidic pH of a metabisulfite solution makes it ideal for acidifying and preserving high-sugar food systems, while the decomposition temperature dictates safe storage away from heat sources.
Sodium metabisulfite is traded primarily in two purity specifications: industrial grade (typically 97–98% Na₂S₂O₅) and food grade (≥98% plus strict limits on iron, arsenic, and heavy metals). The property differences may seem subtle, but they have outsized impacts in sensitive applications.
Industrial grade (97–98%): Optimized for water treatment, gold mining (cyanide destruction), and pulp & paper bleaching. A lower assay of 97% still supplies more than 65% equivalent SO₂ content, but the 1–2% inert salts or sulfate residues can affect clarity in closed-loop water systems. Buyers should monitor iron content (<0.003% typical), since dissolved iron can catalyze unwanted oxidation or stain pulp.
Food grade (FCC/E223): Must meet purity thresholds for arsenic (≤3 mg/kg), lead (≤2 mg/kg), and selenium. The absence of chloride by-products ensures no off-flavors in wine or dried fruit. At Hailei Chemical, our food-grade sodium metabisulfite is manufactured under rigorous HACCP-guided protocols to guarantee compliance with international food safety standards.
When specifying your purchase, always request a Certificate of Analysis (COA) detailing assay, SO₂ content, pH of 10% solution, iron, heavy metals, and water-insoluble matter. The sodium metabisulfite product page provides typical Hailei COA ranges to simplify your comparison.
Many industrial buyers wonder about the interchangeability of sodium bisulfite and sodium metabisulfite. While both provide SO₂ in solution, their chemical properties lead to different dosing behaviors and storage considerations.
| Property | Sodium Metabisulfite (Na₂S₂O₅) | Sodium Bisulfite (NaHSO₃) |
|---|---|---|
| Physical form | Dry crystalline powder/granules | Often supplied as solution (approx. 40%) or crystalline solid (less stable) |
| SO₂ equivalent | Approx. 65–67% by weight | Approx. 22–24% in commercial solutions; solid bisulfite contains 60–65% but is hygroscopic |
| pH of solution | 4.0–5.5 (10% solution) | 2.5–4.0 (solution), more acidic |
| Stability in storage | Excellent when kept dry; >12 months shelf life | Solution prone to oxidation by air; solid form absorbs moisture rapidly |
| Shipping | Dry bulk; cost-effective long-distance shipping | Solution requires tankers or IBCs; higher freight per active SO₂ |
| Typical applications | Water dechlorination, gold mining, food preservative, pulp bleaching, textile | On-site chlorine neutralization, reducing agent in chemical synthesis, leather tanning |
The choice often boils down to logistics and pH buffering. For intercontinental shipments where freight cost and product stability matter, dry sodium metabisulfite is the preferred form. Upon dissolution in water, it forms sodium bisulfite ions, delivering the same reducing action. However, if your process demands immediate solution without handling dry powder, a pre-made bisulfite solution might be convenient—though it costs more per kilogram of SO₂ delivered. Hailei supplies both dry sodium metabisulfite and can direct you to logistics partners for sodium bisulfite solutions where needed.
Knowing how to use sodium metabisulphite safely and efficiently starts with respecting its reactivity profile. The compound’s core property is its ability to release sulfur dioxide in acidic conditions or when heated, making it a potent oxygen scavenger and antimicrobial agent.
In municipal and industrial water treatment, sodium metabisulfite instantly neutralizes free chlorine and chloramines. The stoichiometric reaction requires 1.34 parts of pure Na₂S₂O₅ per part of chlorine. A typical dosing rate is 2–3 mg/L of a 10% metabisulfite solution per mg/L residual chlorine, adjusted for mixing efficiency. Because the reaction drops pH slightly, systems with low alkalinity may need buffering.
The SO₂/air process (INCO method) uses metabisulfite as the SO₂ source to oxidize cyanides (CN⁻) to cyanate (OCN⁻), catalyzed by copper. The reducing property here must be carefully controlled: a solution pH between 8.5 and 9.5 optimizes cyanide destruction while minimizing off-gassing of HCN. Miners often dose metabisulfite at 2–4 grams per gram of WAD cyanide.
As an E223 additive, sodium metabisulfite inhibits enzymatic and non-enzymatic browning in dried fruits, frozen seafood, and wine. The effective SO₂ concentration for antimicrobial action is 50–400 ppm, depending on the product. Its ability to lower pH helps stabilize ascorbic acid and color. Importantly, residual sulfite must meet local labeling laws—typically <10 ppm SO₂ in final product.
In mechanical pulping, metabisulfite acts as a reducing bleach to brighten lignin-rich pulps without degrading cellulose. The property of preserving fiber strength while increasing brightness by 5–8 ISO points makes it valuable for newsprint and tissue grades. Typical application: 1–3% on oven-dry pulp at pH 5–6.
After chlorine bleaching, fabrics carry residual chlorine that can yellow or weaken fibers. A 0.5–2 g/L sodium metabisulfite bath, based on its rapid dechlorination property, eliminates this risk. The slightly acidic pH helps close fiber cuticles, improving dye uptake in subsequent steps.
For detailed application recipes and custom formulation support, refer to our comprehensive sodium metabisulfite application guide.
Procuring sodium metabisulfite without verifying properties against recognized standards can lead to inconsistent batch performance, rejected shipments, or even plant shutdowns. A rigorous supplier evaluation framework should include the following analytical benchmarks.
Request a batch-specific COA with every shipment. Third-party testing by SGS, Bureau Veritas, or Intertek adds an extra layer of trust. Hailei Chemical routinely arranges pre-shipment inspections against these parameters to ensure that the properties of sodium metabisulfite you order are exactly what you receive.
The shelf life and performance of sodium metabisulfite depend critically on storage conditions. Exposure to moisture and heat degrades its reducing power and turns the powder into a hard, unworkable mass.
Key recommendations:
Understanding these environmental sensitivities allows you to plan inventory turnover and avoid waste, directly protecting your investment in each purchased ton.
India is one of the world’s largest importers of sodium metabisulfite, driven by expansive water treatment programs, a massive gold import sector, and a growing food processing industry. If you are seeking a sodium metabisulfite supplier in India, working directly with a chemical exporter in China can often offer cost advantages of 12–18% compared to local distributors, provided you manage shipping and quality inspection efficiently.
Hailei Chemical serves Indian buyers through Nhava Sheva, Mundra, Chennai, and Kolkata ports. Our typical packaging in 25 kg HDPE bags with inner liner is palletized and shrink-wrapped for tropical climates. We also offer 1000–1250 kg big bags and custom private labeling. For oil & gas or mining tenders, we provide full documentation: COA, MSDS, Certificate of Origin, and fumigation certificates as required by Indian customs (HS Code 28321010).
The same logistics expertise applies to buyers in the Middle East (Jebel Ali, Dammam), Southeast Asia, and Africa. Our in-house team coordinates FCL and LCL shipments, transit times, and demurrage avoidance. By consolidating volumes, we help you optimize landed costs without compromising the high purity and consistent properties of sodium metabisulfite you require.
Since 2005, Weifang Hailei Fine Chemical Co., Ltd. has been manufacturing and exporting sulfur-based chemicals under strict ISO 9001 and industry-specific certifications. Our sodium metabisulfite is produced in a dedicated facility with advanced crystallization controls, ensuring every batch meets the precise physical and chemical properties detailed in this guide. We maintain ready stock in our warehouse, enabling 7–15 day lead times for standard FCL orders.
When you partner with Hailei, you gain:
Don’t leave your procurement to chance. If you need a reliable supply of sodium metabisulfite that matches the property specifications critical to your operation, request a quote today. Visit our sodium metabisulfite product page to download the latest COA, MSDS, and application brochures, and let us customize a shipment that meets your exact volume and grading needs.
For procurement managers and chemical engineers sourcing bulk reducing agents, a thorough understanding of the properties of sodium metabisulfite is the foundation of successful formulation, safe handling, and cost-effective supply chain management. From water dechlorination at municipal treatment plants to cyanide detoxification in gold mines and sulfite preservation in food processing, this versatile inorganic compound delivers reliable performance only when its chemical and physical characteristics align with end-use requirements.
At Weifang Hailei Fine Chemical Co., Ltd., we supply sodium metabisulfite (Na₂S₂O₅, CAS 7681-57-4) in both food-grade (FCC compliant) and industrial-grade (97–98% purity) to buyers across India, Southeast Asia, Africa, and the Middle East. This guide decodes every property you need to evaluate before issuing a purchase order, helping you avoid caking in storage, insufficient SO₂ release, or regulatory non-compliance.
Understanding what is sodium metabisulfite made from clarifies its inherent properties. Industrially, sodium metabisulfite is produced by saturating a sodium carbonate or sodium hydroxide solution with sulfur dioxide (SO₂). The exothermic reaction first forms sodium bisulfite (NaHSO₃) in solution, which is then carefully dehydrated through cooling and controlled crystallization to yield solid sodium metabisulfite:
2 NaHSO₃(aq) → Na₂S₂O₅(s) + H₂O
The product is a white to yellowish crystalline powder or granular material with a pungent SO₂ odor. Because its synthesis relies on high-purity SO₂ gas and a low-iron process environment, the quality of inputs directly determines the final product’s heavy metal profile and clarity in solution. For food-grade material, additional purification steps ensure compliance with FCC or E223 monographs, making it safe for use as a preservative in dried fruits, wines, and starch syrups.
A technical evaluation begins with the core properties of sodium metabisulfite. These data points influence dissolution rates, dosing precision, and compatibility with other process chemicals.
These parameters are not just laboratory curiosities—they directly affect real-world outcomes. For instance, the acidic pH of a metabisulfite solution makes it ideal for acidifying and preserving high-sugar food systems, while the decomposition temperature dictates safe storage away from heat sources.
Sodium metabisulfite is traded primarily in two purity specifications: industrial grade (typically 97–98% Na₂S₂O₅) and food grade (≥98% plus strict limits on iron, arsenic, and heavy metals). The property differences may seem subtle, but they have outsized impacts in sensitive applications.
Industrial grade (97–98%): Optimized for water treatment, gold mining (cyanide destruction), and pulp & paper bleaching. A lower assay of 97% still supplies more than 65% equivalent SO₂ content, but the 1–2% inert salts or sulfate residues can affect clarity in closed-loop water systems. Buyers should monitor iron content (<0.003% typical), since dissolved iron can catalyze unwanted oxidation or stain pulp.
Food grade (FCC/E223): Must meet purity thresholds for arsenic (≤3 mg/kg), lead (≤2 mg/kg), and selenium. The absence of chloride by-products ensures no off-flavors in wine or dried fruit. At Hailei Chemical, our food-grade sodium metabisulfite is manufactured under rigorous HACCP-guided protocols to guarantee compliance with international food safety standards.
When specifying your purchase, always request a Certificate of Analysis (COA) detailing assay, SO₂ content, pH of 10% solution, iron, heavy metals, and water-insoluble matter. The sodium metabisulfite product page provides typical Hailei COA ranges to simplify your comparison.
Many industrial buyers wonder about the interchangeability of sodium bisulfite and sodium metabisulfite. While both provide SO₂ in solution, their chemical properties lead to different dosing behaviors and storage considerations.
| Property | Sodium Metabisulfite (Na₂S₂O₅) | Sodium Bisulfite (NaHSO₃) |
|---|---|---|
| Physical form | Dry crystalline powder/granules | Often supplied as solution (approx. 40%) or crystalline solid (less stable) |
| SO₂ equivalent | Approx. 65–67% by weight | Approx. 22–24% in commercial solutions; solid bisulfite contains 60–65% but is hygroscopic |
| pH of solution | 4.0–5.5 (10% solution) | 2.5–4.0 (solution), more acidic |
| Stability in storage | Excellent when kept dry; >12 months shelf life | Solution prone to oxidation by air; solid form absorbs moisture rapidly |
| Shipping | Dry bulk; cost-effective long-distance shipping | Solution requires tankers or IBCs; higher freight per active SO₂ |
| Typical applications | Water dechlorination, gold mining, food preservative, pulp bleaching, textile | On-site chlorine neutralization, reducing agent in chemical synthesis, leather tanning |
The choice often boils down to logistics and pH buffering. For intercontinental shipments where freight cost and product stability matter, dry sodium metabisulfite is the preferred form. Upon dissolution in water, it forms sodium bisulfite ions, delivering the same reducing action. However, if your process demands immediate solution without handling dry powder, a pre-made bisulfite solution might be convenient—though it costs more per kilogram of SO₂ delivered. Hailei supplies both dry sodium metabisulfite and can direct you to logistics partners for sodium bisulfite solutions where needed.
Knowing how to use sodium metabisulphite safely and efficiently starts with respecting its reactivity profile. The compound’s core property is its ability to release sulfur dioxide in acidic conditions or when heated, making it a potent oxygen scavenger and antimicrobial agent.
In municipal and industrial water treatment, sodium metabisulfite instantly neutralizes free chlorine and chloramines. The stoichiometric reaction requires 1.34 parts of pure Na₂S₂O₅ per part of chlorine. A typical dosing rate is 2–3 mg/L of a 10% metabisulfite solution per mg/L residual chlorine, adjusted for mixing efficiency. Because the reaction drops pH slightly, systems with low alkalinity may need buffering.
The SO₂/air process (INCO method) uses metabisulfite as the SO₂ source to oxidize cyanides (CN⁻) to cyanate (OCN⁻), catalyzed by copper. The reducing property here must be carefully controlled: a solution pH between 8.5 and 9.5 optimizes cyanide destruction while minimizing off-gassing of HCN. Miners often dose metabisulfite at 2–4 grams per gram of WAD cyanide.
As an E223 additive, sodium metabisulfite inhibits enzymatic and non-enzymatic browning in dried fruits, frozen seafood, and wine. The effective SO₂ concentration for antimicrobial action is 50–400 ppm, depending on the product. Its ability to lower pH helps stabilize ascorbic acid and color. Importantly, residual sulfite must meet local labeling laws—typically <10 ppm SO₂ in final product.
In mechanical pulping, metabisulfite acts as a reducing bleach to brighten lignin-rich pulps without degrading cellulose. The property of preserving fiber strength while increasing brightness by 5–8 ISO points makes it valuable for newsprint and tissue grades. Typical application: 1–3% on oven-dry pulp at pH 5–6.
After chlorine bleaching, fabrics carry residual chlorine that can yellow or weaken fibers. A 0.5–2 g/L sodium metabisulfite bath, based on its rapid dechlorination property, eliminates this risk. The slightly acidic pH helps close fiber cuticles, improving dye uptake in subsequent steps.
For detailed application recipes and custom formulation support, refer to our comprehensive sodium metabisulfite application guide.
Procuring sodium metabisulfite without verifying properties against recognized standards can lead to inconsistent batch performance, rejected shipments, or even plant shutdowns. A rigorous supplier evaluation framework should include the following analytical benchmarks.
Request a batch-specific COA with every shipment. Third-party testing by SGS, Bureau Veritas, or Intertek adds an extra layer of trust. Hailei Chemical routinely arranges pre-shipment inspections against these parameters to ensure that the properties of sodium metabisulfite you order are exactly what you receive.
The shelf life and performance of sodium metabisulfite depend critically on storage conditions. Exposure to moisture and heat degrades its reducing power and turns the powder into a hard, unworkable mass.
Key recommendations:
Understanding these environmental sensitivities allows you to plan inventory turnover and avoid waste, directly protecting your investment in each purchased ton.
India is one of the world’s largest importers of sodium metabisulfite, driven by expansive water treatment programs, a massive gold import sector, and a growing food processing industry. If you are seeking a sodium metabisulfite supplier in India, working directly with a chemical exporter in China can often offer cost advantages of 12–18% compared to local distributors, provided you manage shipping and quality inspection efficiently.
Hailei Chemical serves Indian buyers through Nhava Sheva, Mundra, Chennai, and Kolkata ports. Our typical packaging in 25 kg HDPE bags with inner liner is palletized and shrink-wrapped for tropical climates. We also offer 1000–1250 kg big bags and custom private labeling. For oil & gas or mining tenders, we provide full documentation: COA, MSDS, Certificate of Origin, and fumigation certificates as required by Indian customs (HS Code 28321010).
The same logistics expertise applies to buyers in the Middle East (Jebel Ali, Dammam), Southeast Asia, and Africa. Our in-house team coordinates FCL and LCL shipments, transit times, and demurrage avoidance. By consolidating volumes, we help you optimize landed costs without compromising the high purity and consistent properties of sodium metabisulfite you require.
Since 2005, Weifang Hailei Fine Chemical Co., Ltd. has been manufacturing and exporting sulfur-based chemicals under strict ISO 9001 and industry-specific certifications. Our sodium metabisulfite is produced in a dedicated facility with advanced crystallization controls, ensuring every batch meets the precise physical and chemical properties detailed in this guide. We maintain ready stock in our warehouse, enabling 7–15 day lead times for standard FCL orders.
When you partner with Hailei, you gain:
Don’t leave your procurement to chance. If you need a reliable supply of sodium metabisulfite that matches the property specifications critical to your operation, request a quote today. Visit our sodium metabisulfite product page to download the latest COA, MSDS, and application brochures, and let us customize a shipment that meets your exact volume and grading needs.
If you’re a procurement manager at a water treatment plant in Maharashtra, a food processing unit in Gujarat, or a textile mill in Tamil Nadu, the sodium metabisulfite price in India is more than a line item—it’s a critical cost driver that directly impacts your production margins. India imported over 28,000 metric tonnes of sodium metabisulfite (SMBS) in 2024, primarily from China, and price volatility remains a constant challenge. Whether you need food grade Na₂S₂O₅ for fruit preservation or industrial grade for dechlorination and gold mining, understanding the pricing dynamics, supply chain logistics, and quality specifications can help you lock in the best deals before market shifts catch you off guard.
This guide will walk you through every facet of the Indian sodium metabisulfite market—where the product comes from, how freight and duties influence landed cost, how to read specifications correctly, and the smart procurement tactics that leading Indian buyers already use. You’ll also get a clear comparison of sodium metabisulfite versus potassium nitrate (yes, that’s a real buyer question), and a detailed view of sodium sulphite specification as a benchmark for chemical performance. By the end, you’ll have the framework to negotiate better rates and evaluate Chinese suppliers like Hailei Chemical with confidence.
Sodium metabisulfite (Na₂S₂O₅), also known as sodium pyrosulfite, is a white crystalline or granular powder with a pungent sulfur dioxide odor. Its CAS number—7681-57-4—is the universal identifier you’ll see on every certificate of analysis (COA) and import document. The compound releases SO₂ when dissolved in water, making it a powerful reducing agent used across at least five major Indian industries:
With such broad utility, the sodium metabisulfite price in India is influenced not just by one sector’s demand, but by the combined pull of all these industries. A spike in gold prices often triggers more mining activity and higher SMBS consumption in the same quarter that post-monsoon water treatment demand peaks—creating a perfect storm for buyers.
Indian buyers often ask why the price per metric ton can swing ₹2–4/Kg within a single quarter. Here’s what’s moving the needle in 2025:
Sodium metabisulfite is synthesized from soda ash (sodium carbonate) and sulfur dioxide. China’s domestic soda ash prices—tied to energy and ammonia costs—directly correlate with SMBS factory pricing. When thermal coal prices in Shanxi province rise, the CIF price for Indian ports follows within 4–6 weeks. Sulfur, often sourced from oil refining desulfurization, tracks global crude oil trends. A buyer monitoring freight rates alone misses half the picture.
Most SMBS containers depart from Qingdao, Shanghai, or Tianjin ports and arrive at Nhava Sheva, Mundra, Chennai, or Kolkata. Average 40′ container freight from China to India in early 2025 stabilized around USD 1,200–1,600, but Red Sea disruptions can still push spot rates 30% higher. Demurrage and detention charges at Indian ports—especially during peak festival season—add hidden costs that many first-time importers overlook.
Sodium metabisulfite falls under HS Code 28321090. The basic customs duty (BCD) is 7.5%, and integrated GST (IGST) of 18% applies on the assessable value (CIF + BCD). Social welfare surcharge (10% of BCD) adds a minor layer. Effective duty burden can push total landed cost 28–32% above CIF price. Buyers who negotiate on CIF alone risk a rude shock when the tax invoice arrives.
Since most China–India transactions settle in USD, the INR/USD exchange rate directly impacts the sodium metabisulfite price in India. A weakening rupee from 82 to 85 against the dollar can inflate landed cost by nearly 3.6% even if the supplier’s ex-works price remains unchanged.
Water treatment demand surges post-monsoon (September–November) when residual chlorine spikes. Food grade demand climbs during mango pulp processing (March–June) and grape harvest seasons. Smart buyers place annual contracts in December–January to average out these peaks.
While spot rates change weekly, a realistic CIF India price band for food grade (E223, purity ≥97.5%, SO₂ ≥65%) from a quality Chinese supplier sits between USD 480 and 520 per metric ton in 2025. Industrial grade (98% purity, heavy metal controlled) trades USD 430–470 CIF depending on quantity and packaging. Converted at ₹85/USD and adding duties, an industrial importer lands SMBS at roughly ₹48–53/Kg ex-warehouse. These are not absolute numbers but reference points to gauge quotes.
Be suspicious of offers below USD 400 CIF. They often mask lower purity (below 96%), excessive iron content (>30 ppm) that ruins textile bleach applications, or the wrong pH profile. A COA that looks too good to be true usually is.
Answering where does sodium metabisulfite come from reveals why your supplier’s location is a competitive advantage. Over 60% of the global SMBS capacity sits in China’s Shandong, Jiangsu, and Tianjin provinces, with Weifang alone host to several large-scale manufacturers like Hailei Chemical. India has limited domestic production (<15% of consumption), so dependence on Chinese imports will remain deep for the next decade.
The manufacturing process typically involves reacting soda ash with SO₂ gas in saturated solution, crystallizing, centrifuging, and drying. Superior plants use closed-loop SO₂ recovery systems to maintain consistent crystal size and free-flowing properties—critical for food processors who won’t accept caking. When evaluating a supplier, trace the product’s sodium metabisulfite origin back to a facility with ISO 9001, ISO 14001, and HACCP certificates. These aren’t just wall decorations; they ensure batch-to-batch consistency that prevents spoiled shipments.
Some European and Turkish producers serve niche markets, but their freight cost to India is prohibitive for bulk consumers. For Indian ports, the Chinese supply chain—mature, cost-optimized, and container-ready—remains the rational choice.
Buyers often ask for “sodium sulphite” when they actually need sodium metabisulfite, or vice versa. The two chemicals share a similar sulfur base but serve different operational purposes. Clarifying the sodium sulphite specification versus SMBS parameters helps avoid procurement errors that stall production lines.
Sodium sulphite (Na₂SO₃) appears as white crystals or powder, has a lower SO₂ equivalent (about 50% vs 65% in SMBS), and is primarily used as an oxygen scavenger in boiler water treatment and photographic developing. It does not release SO₂ as rapidly as metabisulfite and offers a milder reduction potential. For applications like gold cyanide detox or heavy-duty dechlorination, metabisulfite works faster and at lower dosage rates.
Here is a practical specification comparison every Indian buyer should keep handy:
| Parameter | Sodium Metabisulfite (Food Grade) | Sodium Metabisulfite (Industrial Grade) | Sodium Sulphite (Anhydrous) |
|---|---|---|---|
| Chemical Formula | Na₂S₂O₅ | Na₂S₂O₅ | Na₂SO₃ |
| CAS Number | 7681-57-4 | 7681-57-4 | 7757-83-7 |
| Purity (as %) | ≥97.5% | ≥98% | ≥96% |
| SO₂ Content | ≥65% | ≥65% | ~50% (theoretical) |
| Iron (Fe), ppm | ≤10 | ≤30 | ≤20 |
| pH (5% solution) | 4.0–4.6 | 4.0–4.8 | 8.5–10.0 |
| Typical Uses in India | Fruit drying, shrimp preservation, wine | Water dechlorination, mining, textiles | Boiler feed O₂ scavenger, photo fixing |
Notice how SMBS has an acidic pH, while sodium sulphite is alkaline. Piping or tank materials that tolerate one may corrode with the other. When you request a quotation, always specify not just “sodium sulphite specification” or “SMBS purity” but also the full intended application so the supplier configures the right crystal size, anti-caking treatment, and packaging.
This comparison surfaces frequently among food technologists and buyers in the Indian processed food sector. Though both compounds carry an “E number” and appear in preservation contexts, their chemical roles are quite distinct:
The overlap occurs when a processor considers “preservatives” broadly. But using sodium metabisulfite in cured meat would be disastrous—flavor, safety, and regulatory compliance would all fail. Conversely, adding potassium nitrate to fruit pulp is nonsensical. So when Indian buyers compare sodium metabisulfite vs potassium nitrate, the real decision is about process design: if you’re handling fruit & vegetable processing or seafood, SMBS is your agent. If you’re in meat curing, potassium nitrate—often blended with sodium nitrite—is the standard.
A practical takeaway: Never let a supplier substitute one for the other simply based on price. A lower-cost preservative that causes a product recall will erase years of brand equity.
Indian buyers know that not all Chinese exporters deliver the same value. At Hailei Chemical, we’ve structured our factory operations to serve importers who care about consistency and compliance. Our sodium metabisulfite product page details both food grade and industrial grade variants, each with a guaranteed purity floor (97% for food, 98% for industrial), heavy metal profiles below FSSAI/CODEX limits, and anti-caking treatment for the humid Indian climate.
We also understand that Indian import clearance sometimes demands additional documentation. We routinely provide:
Our logistics team books container space with top carriers (Maersk, COSCO, OOCL) and coordinates with your Indian clearing agent to minimize port delays. We also offer flexible packaging from 25 Kg HDPE bags to 1,000 Kg supersacks, reducing unpacking labor at your facility.
For buyers focused squarely on the sodium metabisulfite price in India, we work on transparent CIF or CFR contracts with no hidden loading charges. Because we control the complete soda ash-to-SMBS value chain, we can offer stable pricing that absorbs moderate raw material swings—something traders cannot match.
Whether you’re a first-time importer or expanding your vendor base, following this checklist will protect you from quality disputes and cost overruns:
Indian procurement teams often rely on price haggling, but a strategic buyer can secure better terms by:
Remember, the cheapest quoted CIF price rarely translates to the lowest landed cost when quality failures lead to rejection or line downtime. That’s why clients return to Hailei Chemical not just for the sodium metabisulfite price in India, but for the total procurement reliability we deliver.
The Indian market for sodium metabisulfite will continue to grow, fueled by urbanization, stricter wastewater norms, gold mining expansions, and a booming food processing sector. By understanding where this chemical comes from, how quality specs like sodium sulphite data parallel your needs, and what truly drives pricing, you position yourself as a savvier buyer. And when the inevitable price cycle turns, you’ll be the one with a locked-in contract, not the one scrambling for spot cargo.
Whether your operation needs consistent sodium metabisulfite cas no 7681-57-4 product, bulk containers on a reliable schedule, or detailed guidance on import regulations, Hailei Chemical is ready to partner. Our technical team speaks your language of chemical engineering, not just sales scripts.
Take the next step: Request a personalized quotation today for food grade or industrial grade sodium metabisulfite, and let us show you how Chinese manufacturing excellence can deliver unbeatable value to your doorstep in India.