Whether you source chemicals for a municipal water treatment plant, a gold mine in India, or a food processing facility, understanding the properties of sodium metabisulfite is critical to making safe, cost-effective, and performance-driven procurement decisions. Sodium metabisulfite (Na2S2O5, CAS 7681-57-4) is a versatile inorganic sulfite used globally for dechlorination, cyanide detoxification, food preservation, pulp bleaching, and textile anti-chlorine treatment. Yet many buyers overlook how the product’s chemical identity, solubility, stability, and purity directly impact dosage, handling, and final application outcomes. This guide breaks down the essential physical and chemical properties, explains how sodium metabisulfite is made, compares it with sodium bisulfite, and provides practical usage directions—all from the perspective of a procurement manager or process engineer sourcing industrial-grade material.
To use the product effectively, you must first know its core properties. Sodium metabisulfite is a white to yellowish crystalline powder with a pungent sulfur dioxide odor. It is freely soluble in water (54 g/100 mL at 20°C) and slightly soluble in alcohol. The aqueous solution is acidic, with a pH around 4.0–5.5 for a 5% solution, due to the release of sulfurous acid. On a molecular level, sodium metabisulfite is the disodium salt of disulfurous acid (H2S2O5), meaning each molecule contains two sulfur atoms bridged through an S–S bond, which distinguishes it from simple sulfites.
Key physical constants: molecular weight 190.11 g/mol; melting point >150°C with decomposition; apparent density approx. 1.1–1.3 g/cm³. When heated above 150°C, it decomposes, releasing sulfur dioxide (SO2) and leaving sodium sulfite (Na2SO3) and sulfate residues. This thermal behavior is important if your process involves drying or exposure to high temperatures.
The properties of sodium metabisulfite that matter most in industrial use are its strong reducing action in aqueous media and its ability to generate SO2 under acidic conditions. In water, it dissociates into sodium (Na⁺) and metabisulfite ions (S2O52−), which further hydrolyze to bisulfite (HSO3−) and sulfite (SO32−) species. This equilibrium gives it excellent reactivity for removing chlorine, oxygen, and heavy metal oxidants. The high assay (97–98% Na2S2O5 for Hailei Chemical’s food and industrial grades) ensures low iron (≤10 ppm), heavy metals (≤5 ppm as Pb), and minimal insoluble matter, meeting EU, FCC, and USP standards for critical applications.
Understanding the production pathway helps buyers evaluate supply chain consistency and impurity profiles. Sodium metabisulfite is manufactured by reacting sulfur dioxide (SO2) with a sodium base—typically sodium carbonate (soda ash) or sodium hydroxide (caustic soda)—under controlled aqueous conditions. The process can be summarized in two main steps:
High-quality producers—like Hailei Chemical—use food-grade sulfur and purified water, ensuring the final product meets both industrial and food-grade specifications. The choice of sodium source influences residual alkalinity: soda ash yields a product with slightly higher sodium carbonate traces, while NaOH route gives a purer bisulfite intermediate but requires tighter process control. Knowing this helps you request the right certificate of analysis (CoA) for your specific purity and particle size needs.
A common point of confusion is the relationship between sodium bisulfite (NaHSO3) and sodium metabisulfite. While both are sulfite-based reducing agents, their chemical structure and practical behavior differ. Sodium bisulfite is a monoprotic salt of sulfurous acid, typically existing only in aqueous solution or as a labile solid. Sodium metabisulfite, on the other hand, is the dehydrated dimer of sodium bisulfite: two bisulfite ions lose one water molecule to form the S–S bonded metabisulfite. When dissolved in water, sodium metabisulfite hydrolyzes to sodium bisulfite and then to sulfite species, so the active chemistry is often similar. However, there are key practical differences:
For most procurement scenarios involving solid sulfite chemicals, sodium metabisulfite offers better shelf life and concentration. Always verify which form your process actually requires; switching from a liquid bisulfite to dry metabisulfite can cut logistics costs significantly but may require dissolving equipment.
Proper usage hinges on matching the properties of sodium metabisulfite to your process chemistry. Below we cover general guidelines for four key sectors.
In municipal and industrial water treatment, sodium metabisulfite is used to neutralize free chlorine and chloramines before discharge or membrane protection. The stoichiometric reaction is: Na2S2O5 + 3 Cl2 + 5 H2O → 2 NaHSO4 + 6 HCl. Typically, 1.34 mg of pure Na2S2O5 removes 1 mg of Cl2. Because commercial product is ~97% pure, a safety factor of 1.1–1.2 is used. A 10% solution is prepared and dosed via metering pump. Stirring and contact time of 5–15 minutes assure complete dechlorination. Online ORP sensors can automate the feed rate.
In gold leaching operations, residual cyanide must be destroyed to meet tailings discharge limits. Sodium metabisulfite provides SO2 gas in the well-known INCO process, oxidizing cyanide to cyanate. A typical usage rate is 5–10 kg metabisulfite per ton of ore depending on cyanide concentration. A 20% solution is injected into tailings slurry along with copper sulfate catalyst, at pH 8–9, with vigorous air sparging. The technical-grade sodium metabisulfite with high purity and low iron is essential to avoid precipitates that clog nozzles.
As an E223 additive, sodium metabisulfite inhibits enzymatic browning in dried fruits, wines, and vegetable preserves. Dosage varies: 200–500 ppm SO2 equivalent in wine must, or dipping solutions of 1–2% w/v for sliced apples and potatoes. Always use food-grade material that meets FCC/USP standards, free from arsenic and heavy metals. Important: sodium metabisulfite is an allergen; final products must declare sulfite content if above 10 ppm.
In pulp and paper mills, metabisulfite solutions (5–10%) remove residual chlorine-based bleach from pulp before papermaking, preventing yellowing and fiber damage. In textile finishing, it serves as an anti-chlor agent after hypochlorite bleaching to neutralize excess chlorine before dyeing. For both, a gentle reducing environment (pH 4–6, ambient temperature) works best.
India is one of the largest import markets for sodium metabisulfite due to its booming water treatment, mining, and food sectors. If you are searching for a sodium metabisulfite supplier in India, you need a partner who combines consistent product quality with logistics expertise. Hailei Chemical exports bulk sodium metabisulfite to major Indian ports (Nhava Sheva, Chennai, Mundra) in 25 kg woven bags, 1000 kg supersacks, or custom packaging. Our 97–98% purity with low heavy metals and iron aligns with BIS and food additive standards, while our logistical support—including full customs documentation, REACH compliance data, and pre-shipment samples—simplifies your import process.
When qualifying any international supplier, request a detailed CoA showing not just Na2S2O5 assay but also iron, arsenic, selenium, and chloride content. Scrutinize the product’s physical properties like bulk density and particle size distribution (typically 40–120 mesh) if your process uses dry feeders. Hailei Chemical’s technical team can provide specification sheets tailored to your application, ensuring the properties of sodium metabisulfite you receive precisely match your needs.
It is an acidic salt. A 5% aqueous solution has a pH of about 4.0–5.5 due to the formation of sulfurous acid. This mild acidity makes it ideal for reducing environments without drastically altering process pH.
Yes, in many applications. Sodium metabisulfite releases sulfite ions upon dissolution. The main advantage is higher SO2 equivalent per kilogram and better dry stability. However, for some food or pharmaceutical processes requiring precise sodium sulfite, direct substitution should be validated.
Store in a cool, dry, well-ventilated area away from acids and oxidizers. Sealed bags prevent moisture absorption, which would trigger decomposition and caking. Under proper conditions, shelf life exceeds 12 months without significant loss of SO2 content.
A simple iodometric titration determines available SO2 content. If the assay has dropped below your required threshold (e.g., 97%), the product may have degraded due to moisture ingress. Hailei Chemical uses quality-controlled packaging to maintain assay throughout transit.
When sourcing a bulk supply of sodium metabisulfite, having a deep grasp of its properties—from solubility and pH to redox behavior and impurity limits—empowers you to optimize processes and avoid costly misapplications. Whether you need food-grade powder for fruit preservation or industrial-grade crystals for cyanide destruction, our sodium metabisulfite product page provides full specifications and order options. To discuss your volume, packaging, or documentation requirements with our technical sales team, request a competitive quote today.
India’s rapidly expanding water treatment, food processing, and mining sectors have created an unprecedented demand for high-purity sodium metabisulfite. As a procurement manager or industrial buyer, identifying a dependable sodium metabisulfite supplier in India requires more than simply comparing prices per metric ton. You need a partner who delivers consistent quality, navigates complex import regulations, and provides the technical support that keeps your operations running smoothly. This comprehensive guide walks you through every facet of sourcing food grade and industrial grade sodium metabisulfite for the Indian market—from critical quality parameters to logistics optimization and supplier evaluation frameworks.
India’s sodium metabisulfite market has grown at over 6% CAGR in recent years, driven by three megatrends: the government’s Jal Jeevan Mission for universal piped water, accelerating gold production through organized mining, and the food processing industry’s shift toward preservatives that meet FSSAI standards. This surge means that finding a sodium metabisulfite supplier in India—whether domestic or an international exporter with strong India logistics—is a strategic priority for many businesses.
Indian buyers typically fall into these categories:
For these sectors, the supplier must not only offer competitive pricing but also demonstrate adherence to Indian standards and reliable documentation for customs clearance.
While buyers often encounter both sodium bisulfite and sodium metabisulfite in their sourcing journey, their chemical behavior and applications differ markedly. Sodium metabisulfite (Na2S2O5, CAS 7681-57-4) is a white crystalline powder that releases sulfur dioxide (SO2) when dissolved in water, acting as a powerful reducing agent and preservative. In contrast, sodium bisulfite (NaHSO3) exists primarily as a solution and has slightly different stoichiometry in dechlorination reactions. For the most demanding industrial uses of sodium metabisulfite, the dry powder form offers easier storage, longer shelf life, and higher SO2 content per unit weight—typically 65–67.5% available SO2 for a 97% pure product.
Hailei Chemical’s sodium metabisulfite is manufactured to a purity of 97–98%, significantly exceeding the 95% minimum commonly found in spot-market cargoes. This purity level is essential for food grade applications and for mining operations where impurities can interfere with the gold cyanidation process.
When you set out to buy sodium metabisulfite for Indian operations, a systematic supplier assessment prevents costly supply chain failures. Use this five-point framework whether you are engaging a domestic Indian manufacturer or an international exporter like Hailei Chemical’s sodium metabisulfite division.
Food grade sodium metabisulfite must comply with FSSAI regulations and often the Indian Standard IS 4750:1996 (reaffirmed). Request a Certificate of Analysis (CoA) showing purity ≥97%, iron (Fe) ≤ 10 ppm, heavy metals (as Pb) ≤ 5 ppm, and arsenic (As) ≤ 2 ppm. For industrial grade used in water treatment, compliance with IS 248:1978 or relevant BIS standards is expected. A competent sodium metabisulfite supplier in India will proactively provide these documents without being asked.
Indian buyers often import container loads of 20–27 metric tons. Ensure the supplier can allocate consistent production runs rather than spot blending. Ask for batch-to-batch variation data—reputable manufacturers maintain a standard deviation below 0.5% for purity and within 5% for particle size distribution. Hailei Chemical, for instance, operates dedicated production lines with real-time quality monitoring, making them a preferred sodium metabisulfite supplier in India-focused export partner.
Importing chemicals into India requires a comprehensive set of documents: Bill of Lading, Commercial Invoice, Packing List, Certificate of Origin (for duty benefits under trade agreements), MSDS compliant with Indian Occupational Safety and Health standards, and the CoA. A seasoned supplier will also provide pre-shipment inspection certificates from agencies like SGS or Bureau Veritas upon request. These certificates significantly ease clearance at major ports like Nhava Sheva, Mundra, or Chennai.
Sodium metabisulfite is hygroscopic and must be shipped in airtight 25 kg or 50 kg HDPE bags with inner liners, palletized and shrink-wrapped for ocean freight. The ideal supplier coordinates door-to-door delivery, including last-mile transport to locations like Coimbatore, Ahmedabad, or the Kolar gold fields. Ask about their experience with Indian ports—delays at customs can cost thousands of dollars in demurrage. An established sodium metabisulfite supplier in India typically offers CIF Mumbai, Chennai, or Mundra as standard terms.
Different applications require different granularities and anti-caking treatments. A supplier should offer technical guidance on dissolution rates, pH adjustment, and compatibility with other water treatment chemicals like chlorine or ammonia. Hailei Chemical provides free technical consultation to Indian buyers, helping them optimize dosage rates for dechlorination or cyanide detoxification.
When comparing quotations, look beyond the basic purity percentage. The following table summarizes the key parameters for food grade and industrial grade sodium metabisulfite, aligned with Indian market expectations:
| Parameter | Food Grade (FSSAI/IS 4750) | Industrial Grade (IS 248) |
|---|---|---|
| Purity (as Na2S2O5) | ≥97.0% | ≥96.0% |
| SO2 Content | ≥65.0% | ≥65.0% |
| Iron (Fe) | ≤10 ppm | ≤20 ppm |
| Heavy Metals (as Pb) | ≤5 ppm | ≤10 ppm |
| Arsenic (As) | ≤2 ppm | ≤3 ppm |
| Water Insoluble Matter | ≤0.02% | ≤0.05% |
| pH (10% solution) | 4.0–5.0 | 4.0–5.0 |
Hailei Chemical’s standard grade achieves 98% purity, placing it well above these minimums and making it suitable for even the most sensitive food preservation applications.
The use of sodium metabisulfite in food preservation is perhaps the most regulated application in India. FSSAI permits its use as a preservative (INS 223) in specified food categories such as dehydrated vegetables, fruit pulp, dried fruits, jams, and fruit juices, with maximum SO2 residual limits ranging from 100 ppm to 2000 ppm depending on the product. For example, dried apricots may retain up to 2000 ppm, while canned mango pulp is limited to 100 ppm. Food processors must source only food grade material that meets the purity specifications above, and they should request halal or kosher certification if exporting to Middle Eastern or other markets.
Beyond preservation, sodium metabisulfite acts as an antioxidant in seafood processing, preventing black spot formation on shrimp—a major Indian export. It also serves as a dough conditioner in biscuit manufacturing, improving extensibility. A trustworthy sodium metabisulfite supplier in India should be able to provide documentation that traces each batch from production to delivery, supporting your own FSSAI compliance audits.
Across India, as new sewage treatment plants (STPs) and drinking water facilities come online, the need for efficient dechlorination has skyrocketed. Sodium metabisulfite neutralizes chlorine and chloramine instantly via a redox reaction, and the stoichiometric dose is approximately 1.34 mg of Na2S2O5 per 1 mg of chlorine. For a plant handling 50 million liters per day with a residual chlorine of 2 mg/L, that translates to around 134 kg of product daily. Indian plant engineers favor the dry powder because it can be stored in bulk silos and fed by gravimetric feeders, reducing operator exposure compared to liquid bisulfite solutions.
India’s gold mines, particularly those in the Hutti-Maski greenstone belt and the expanding operations in Jharkhand, rely on cyanide extraction. After leaching, the tailings must be treated to destroy residual free cyanide and metal-cyanide complexes. Sodium metabisulfite with a catalyst like copper sulfate is a proven air-SO2 process method, converting cyanide to less toxic cyanate. The reaction demands a consistent, high-purity product—impurities can reduce efficiency and increase treatment time. This is the very application where the purity of Hailei Chemical’s sodium metabisulfite delivers a measurable return on investment.
In textile processing, fabric bleached with hypochlorite carries residual chlorine that must be neutralized before dyeing, otherwise it causes uneven coloration. Sodium metabisulfite is the preferred anti-chlorine agent because it leaves no residue that could interfere with reactive dyes. Similarly, in the pulp and paper industry—particularly in mills across Maharashtra and Gujarat—it is used to eliminate excess chlorine after the bleaching stage, protecting paper quality and reducing AOX emissions into the environment. These applications require industrial grade material with low heavy metal content to avoid spotting on final products.
The decision between sodium bisulfite and sodium metabisulfite often hinges on logistics and dosage form. Sodium bisulfite is typically available as a 30–40% solution, which is convenient for plants with existing liquid chemical feeds but incurs higher shipping costs because you are transporting mostly water. Sodium metabisulfite, a dry powder, reduces freight cost per active kilogram by up to 60% and offers better storage stability—critical in the humid Indian climate, provided the bags remain sealed. Once dissolved, the chemistry is essentially the same: the metabisulfite hydrolyzes to bisulfite ions. For Indian buyers who value flexible inventory and lower inland logistics expenses, the powder form from an experienced sodium metabisulfite supplier in India is almost always the more economical long-term choice.
When you buy sodium metabisulfite from an international supplier, understanding the import flow is essential to avoid demurrage and detention charges. The cargo typically departs from major Chinese ports such as Qingdao or Shanghai and arrives at India’s west coast ports within 15–20 days. Upon arrival, the importer must file a Bill of Entry under Customs Tariff Heading 2832.20 for sulfites. Duty rates are generally 7.5% basic customs duty plus applicable IGST of 18%, though rates may vary under the India-ASEAN FTA or other trade policies.
Top tips for smooth importation:
A supplier well-versed in India shipping can provide CIF delivery to Mundra, Chennai, or ICD Delhi, and even help arrange last-mile transport to your facility. This is a hallmark of a true logistics-savvy sodium metabisulfite supplier in India.
The lowest per-ton price on a commercial invoice rarely translates to the lowest total cost. Consider these hidden factors:
When you partner with Hailei Chemical, you receive 98% pure sodium metabisulfite packed in heavy-duty 25 kg bags, fully palletized, with a 100% on-time documentation record. The slight premium over generic suppliers is quickly offset by lower operational risk and higher process stability—a value proposition appreciated by procurement managers across India.
Beyond the checklist earlier, perform these due diligence steps before placing an order:
Whether your operation involves uses of sodium metabisulfite in municipal water dechlorination, food preservation, gold mining cyanide destruction, or textile processing, the choice of supplier directly influences your product quality, regulatory compliance, and bottom line. A reliable sodium metabisulfite supplier in India goes beyond commodity brokering—they become a partner in your supply chain resilience. By insisting on documented purity, Indian standard compliance, intelligent logistics support, and transparent pricing, you turn a chemical purchase into a competitive advantage.
Hailei Chemical has decades of experience producing and exporting premium sodium metabisulfite to Indian buyers. Our team understands the nuances of FSSAI requirements, mining industry performance demands, and the logistics of delivering to any Indian port efficiently. We are ready to support your business with consistent quality and technical expertise.
Ready to discuss your sodium metabisulfite requirements? Request a quotation or contact our India-desk team for a personalized consultation. Explore our full product specifications at sodium metabisulfite product page.
India’s rapidly expanding water treatment, food processing, and mining sectors have created an unprecedented demand for high-purity sodium metabisulfite. As a procurement manager or industrial buyer, identifying a dependable sodium metabisulfite supplier in India requires more than simply comparing prices per metric ton. You need a partner who delivers consistent quality, navigates complex import regulations, and provides the technical support that keeps your operations running smoothly. This comprehensive guide walks you through every facet of sourcing food grade and industrial grade sodium metabisulfite for the Indian market—from critical quality parameters to logistics optimization and supplier evaluation frameworks.
India’s sodium metabisulfite market has grown at over 6% CAGR in recent years, driven by three megatrends: the government’s Jal Jeevan Mission for universal piped water, accelerating gold production through organized mining, and the food processing industry’s shift toward preservatives that meet FSSAI standards. This surge means that finding a sodium metabisulfite supplier in India—whether domestic or an international exporter with strong India logistics—is a strategic priority for many businesses.
Indian buyers typically fall into these categories:
For these sectors, the supplier must not only offer competitive pricing but also demonstrate adherence to Indian standards and reliable documentation for customs clearance.
While buyers often encounter both sodium bisulfite and sodium metabisulfite in their sourcing journey, their chemical behavior and applications differ markedly. Sodium metabisulfite (Na2S2O5, CAS 7681-57-4) is a white crystalline powder that releases sulfur dioxide (SO2) when dissolved in water, acting as a powerful reducing agent and preservative. In contrast, sodium bisulfite (NaHSO3) exists primarily as a solution and has slightly different stoichiometry in dechlorination reactions. For the most demanding industrial uses of sodium metabisulfite, the dry powder form offers easier storage, longer shelf life, and higher SO2 content per unit weight—typically 65–67.5% available SO2 for a 97% pure product.
Hailei Chemical’s sodium metabisulfite is manufactured to a purity of 97–98%, significantly exceeding the 95% minimum commonly found in spot-market cargoes. This purity level is essential for food grade applications and for mining operations where impurities can interfere with the gold cyanidation process.
When you set out to buy sodium metabisulfite for Indian operations, a systematic supplier assessment prevents costly supply chain failures. Use this five-point framework whether you are engaging a domestic Indian manufacturer or an international exporter like Hailei Chemical’s sodium metabisulfite division.
Food grade sodium metabisulfite must comply with FSSAI regulations and often the Indian Standard IS 4750:1996 (reaffirmed). Request a Certificate of Analysis (CoA) showing purity ≥97%, iron (Fe) ≤ 10 ppm, heavy metals (as Pb) ≤ 5 ppm, and arsenic (As) ≤ 2 ppm. For industrial grade used in water treatment, compliance with IS 248:1978 or relevant BIS standards is expected. A competent sodium metabisulfite supplier in India will proactively provide these documents without being asked.
Indian buyers often import container loads of 20–27 metric tons. Ensure the supplier can allocate consistent production runs rather than spot blending. Ask for batch-to-batch variation data—reputable manufacturers maintain a standard deviation below 0.5% for purity and within 5% for particle size distribution. Hailei Chemical, for instance, operates dedicated production lines with real-time quality monitoring, making them a preferred sodium metabisulfite supplier in India-focused export partner.
Importing chemicals into India requires a comprehensive set of documents: Bill of Lading, Commercial Invoice, Packing List, Certificate of Origin (for duty benefits under trade agreements), MSDS compliant with Indian Occupational Safety and Health standards, and the CoA. A seasoned supplier will also provide pre-shipment inspection certificates from agencies like SGS or Bureau Veritas upon request. These certificates significantly ease clearance at major ports like Nhava Sheva, Mundra, or Chennai.
Sodium metabisulfite is hygroscopic and must be shipped in airtight 25 kg or 50 kg HDPE bags with inner liners, palletized and shrink-wrapped for ocean freight. The ideal supplier coordinates door-to-door delivery, including last-mile transport to locations like Coimbatore, Ahmedabad, or the Kolar gold fields. Ask about their experience with Indian ports—delays at customs can cost thousands of dollars in demurrage. An established sodium metabisulfite supplier in India typically offers CIF Mumbai, Chennai, or Mundra as standard terms.
Different applications require different granularities and anti-caking treatments. A supplier should offer technical guidance on dissolution rates, pH adjustment, and compatibility with other water treatment chemicals like chlorine or ammonia. Hailei Chemical provides free technical consultation to Indian buyers, helping them optimize dosage rates for dechlorination or cyanide detoxification.
When comparing quotations, look beyond the basic purity percentage. The following table summarizes the key parameters for food grade and industrial grade sodium metabisulfite, aligned with Indian market expectations:
| Parameter | Food Grade (FSSAI/IS 4750) | Industrial Grade (IS 248) |
|---|---|---|
| Purity (as Na2S2O5) | ≥97.0% | ≥96.0% |
| SO2 Content | ≥65.0% | ≥65.0% |
| Iron (Fe) | ≤10 ppm | ≤20 ppm |
| Heavy Metals (as Pb) | ≤5 ppm | ≤10 ppm |
| Arsenic (As) | ≤2 ppm | ≤3 ppm |
| Water Insoluble Matter | ≤0.02% | ≤0.05% |
| pH (10% solution) | 4.0–5.0 | 4.0–5.0 |
Hailei Chemical’s standard grade achieves 98% purity, placing it well above these minimums and making it suitable for even the most sensitive food preservation applications.
The use of sodium metabisulfite in food preservation is perhaps the most regulated application in India. FSSAI permits its use as a preservative (INS 223) in specified food categories such as dehydrated vegetables, fruit pulp, dried fruits, jams, and fruit juices, with maximum SO2 residual limits ranging from 100 ppm to 2000 ppm depending on the product. For example, dried apricots may retain up to 2000 ppm, while canned mango pulp is limited to 100 ppm. Food processors must source only food grade material that meets the purity specifications above, and they should request halal or kosher certification if exporting to Middle Eastern or other markets.
Beyond preservation, sodium metabisulfite acts as an antioxidant in seafood processing, preventing black spot formation on shrimp—a major Indian export. It also serves as a dough conditioner in biscuit manufacturing, improving extensibility. A trustworthy sodium metabisulfite supplier in India should be able to provide documentation that traces each batch from production to delivery, supporting your own FSSAI compliance audits.
Across India, as new sewage treatment plants (STPs) and drinking water facilities come online, the need for efficient dechlorination has skyrocketed. Sodium metabisulfite neutralizes chlorine and chloramine instantly via a redox reaction, and the stoichiometric dose is approximately 1.34 mg of Na2S2O5 per 1 mg of chlorine. For a plant handling 50 million liters per day with a residual chlorine of 2 mg/L, that translates to around 134 kg of product daily. Indian plant engineers favor the dry powder because it can be stored in bulk silos and fed by gravimetric feeders, reducing operator exposure compared to liquid bisulfite solutions.
India’s gold mines, particularly those in the Hutti-Maski greenstone belt and the expanding operations in Jharkhand, rely on cyanide extraction. After leaching, the tailings must be treated to destroy residual free cyanide and metal-cyanide complexes. Sodium metabisulfite with a catalyst like copper sulfate is a proven air-SO2 process method, converting cyanide to less toxic cyanate. The reaction demands a consistent, high-purity product—impurities can reduce efficiency and increase treatment time. This is the very application where the purity of Hailei Chemical’s sodium metabisulfite delivers a measurable return on investment.
In textile processing, fabric bleached with hypochlorite carries residual chlorine that must be neutralized before dyeing, otherwise it causes uneven coloration. Sodium metabisulfite is the preferred anti-chlorine agent because it leaves no residue that could interfere with reactive dyes. Similarly, in the pulp and paper industry—particularly in mills across Maharashtra and Gujarat—it is used to eliminate excess chlorine after the bleaching stage, protecting paper quality and reducing AOX emissions into the environment. These applications require industrial grade material with low heavy metal content to avoid spotting on final products.
The decision between sodium bisulfite and sodium metabisulfite often hinges on logistics and dosage form. Sodium bisulfite is typically available as a 30–40% solution, which is convenient for plants with existing liquid chemical feeds but incurs higher shipping costs because you are transporting mostly water. Sodium metabisulfite, a dry powder, reduces freight cost per active kilogram by up to 60% and offers better storage stability—critical in the humid Indian climate, provided the bags remain sealed. Once dissolved, the chemistry is essentially the same: the metabisulfite hydrolyzes to bisulfite ions. For Indian buyers who value flexible inventory and lower inland logistics expenses, the powder form from an experienced sodium metabisulfite supplier in India is almost always the more economical long-term choice.
When you buy sodium metabisulfite from an international supplier, understanding the import flow is essential to avoid demurrage and detention charges. The cargo typically departs from major Chinese ports such as Qingdao or Shanghai and arrives at India’s west coast ports within 15–20 days. Upon arrival, the importer must file a Bill of Entry under Customs Tariff Heading 2832.20 for sulfites. Duty rates are generally 7.5% basic customs duty plus applicable IGST of 18%, though rates may vary under the India-ASEAN FTA or other trade policies.
Top tips for smooth importation:
A supplier well-versed in India shipping can provide CIF delivery to Mundra, Chennai, or ICD Delhi, and even help arrange last-mile transport to your facility. This is a hallmark of a true logistics-savvy sodium metabisulfite supplier in India.
The lowest per-ton price on a commercial invoice rarely translates to the lowest total cost. Consider these hidden factors:
When you partner with Hailei Chemical, you receive 98% pure sodium metabisulfite packed in heavy-duty 25 kg bags, fully palletized, with a 100% on-time documentation record. The slight premium over generic suppliers is quickly offset by lower operational risk and higher process stability—a value proposition appreciated by procurement managers across India.
Beyond the checklist earlier, perform these due diligence steps before placing an order:
Whether your operation involves uses of sodium metabisulfite in municipal water dechlorination, food preservation, gold mining cyanide destruction, or textile processing, the choice of supplier directly influences your product quality, regulatory compliance, and bottom line. A reliable sodium metabisulfite supplier in India goes beyond commodity brokering—they become a partner in your supply chain resilience. By insisting on documented purity, Indian standard compliance, intelligent logistics support, and transparent pricing, you turn a chemical purchase into a competitive advantage.
Hailei Chemical has decades of experience producing and exporting premium sodium metabisulfite to Indian buyers. Our team understands the nuances of FSSAI requirements, mining industry performance demands, and the logistics of delivering to any Indian port efficiently. We are ready to support your business with consistent quality and technical expertise.
Ready to discuss your sodium metabisulfite requirements? Request a quotation or contact our India-desk team for a personalized consultation. Explore our full product specifications at sodium metabisulfite product page.
India’s rapidly expanding water treatment, food processing, and mining sectors have created an unprecedented demand for high-purity sodium metabisulfite. As a procurement manager or industrial buyer, identifying a dependable sodium metabisulfite supplier in India requires more than simply comparing prices per metric ton. You need a partner who delivers consistent quality, navigates complex import regulations, and provides the technical support that keeps your operations running smoothly. This comprehensive guide walks you through every facet of sourcing food grade and industrial grade sodium metabisulfite for the Indian market—from critical quality parameters to logistics optimization and supplier evaluation frameworks.
India’s sodium metabisulfite market has grown at over 6% CAGR in recent years, driven by three megatrends: the government’s Jal Jeevan Mission for universal piped water, accelerating gold production through organized mining, and the food processing industry’s shift toward preservatives that meet FSSAI standards. This surge means that finding a sodium metabisulfite supplier in India—whether domestic or an international exporter with strong India logistics—is a strategic priority for many businesses.
Indian buyers typically fall into these categories:
For these sectors, the supplier must not only offer competitive pricing but also demonstrate adherence to Indian standards and reliable documentation for customs clearance.
While buyers often encounter both sodium bisulfite and sodium metabisulfite in their sourcing journey, their chemical behavior and applications differ markedly. Sodium metabisulfite (Na2S2O5, CAS 7681-57-4) is a white crystalline powder that releases sulfur dioxide (SO2) when dissolved in water, acting as a powerful reducing agent and preservative. In contrast, sodium bisulfite (NaHSO3) exists primarily as a solution and has slightly different stoichiometry in dechlorination reactions. For the most demanding industrial uses of sodium metabisulfite, the dry powder form offers easier storage, longer shelf life, and higher SO2 content per unit weight—typically 65–67.5% available SO2 for a 97% pure product.
Hailei Chemical’s sodium metabisulfite is manufactured to a purity of 97–98%, significantly exceeding the 95% minimum commonly found in spot-market cargoes. This purity level is essential for food grade applications and for mining operations where impurities can interfere with the gold cyanidation process.
When you set out to buy sodium metabisulfite for Indian operations, a systematic supplier assessment prevents costly supply chain failures. Use this five-point framework whether you are engaging a domestic Indian manufacturer or an international exporter like Hailei Chemical’s sodium metabisulfite division.
Food grade sodium metabisulfite must comply with FSSAI regulations and often the Indian Standard IS 4750:1996 (reaffirmed). Request a Certificate of Analysis (CoA) showing purity ≥97%, iron (Fe) ≤ 10 ppm, heavy metals (as Pb) ≤ 5 ppm, and arsenic (As) ≤ 2 ppm. For industrial grade used in water treatment, compliance with IS 248:1978 or relevant BIS standards is expected. A competent sodium metabisulfite supplier in India will proactively provide these documents without being asked.
Indian buyers often import container loads of 20–27 metric tons. Ensure the supplier can allocate consistent production runs rather than spot blending. Ask for batch-to-batch variation data—reputable manufacturers maintain a standard deviation below 0.5% for purity and within 5% for particle size distribution. Hailei Chemical, for instance, operates dedicated production lines with real-time quality monitoring, making them a preferred sodium metabisulfite supplier in India-focused export partner.
Importing chemicals into India requires a comprehensive set of documents: Bill of Lading, Commercial Invoice, Packing List, Certificate of Origin (for duty benefits under trade agreements), MSDS compliant with Indian Occupational Safety and Health standards, and the CoA. A seasoned supplier will also provide pre-shipment inspection certificates from agencies like SGS or Bureau Veritas upon request. These certificates significantly ease clearance at major ports like Nhava Sheva, Mundra, or Chennai.
Sodium metabisulfite is hygroscopic and must be shipped in airtight 25 kg or 50 kg HDPE bags with inner liners, palletized and shrink-wrapped for ocean freight. The ideal supplier coordinates door-to-door delivery, including last-mile transport to locations like Coimbatore, Ahmedabad, or the Kolar gold fields. Ask about their experience with Indian ports—delays at customs can cost thousands of dollars in demurrage. An established sodium metabisulfite supplier in India typically offers CIF Mumbai, Chennai, or Mundra as standard terms.
Different applications require different granularities and anti-caking treatments. A supplier should offer technical guidance on dissolution rates, pH adjustment, and compatibility with other water treatment chemicals like chlorine or ammonia. Hailei Chemical provides free technical consultation to Indian buyers, helping them optimize dosage rates for dechlorination or cyanide detoxification.
When comparing quotations, look beyond the basic purity percentage. The following table summarizes the key parameters for food grade and industrial grade sodium metabisulfite, aligned with Indian market expectations:
| Parameter | Food Grade (FSSAI/IS 4750) | Industrial Grade (IS 248) |
|---|---|---|
| Purity (as Na2S2O5) | ≥97.0% | ≥96.0% |
| SO2 Content | ≥65.0% | ≥65.0% |
| Iron (Fe) | ≤10 ppm | ≤20 ppm |
| Heavy Metals (as Pb) | ≤5 ppm | ≤10 ppm |
| Arsenic (As) | ≤2 ppm | ≤3 ppm |
| Water Insoluble Matter | ≤0.02% | ≤0.05% |
| pH (10% solution) | 4.0–5.0 | 4.0–5.0 |
Hailei Chemical’s standard grade achieves 98% purity, placing it well above these minimums and making it suitable for even the most sensitive food preservation applications.
The use of sodium metabisulfite in food preservation is perhaps the most regulated application in India. FSSAI permits its use as a preservative (INS 223) in specified food categories such as dehydrated vegetables, fruit pulp, dried fruits, jams, and fruit juices, with maximum SO2 residual limits ranging from 100 ppm to 2000 ppm depending on the product. For example, dried apricots may retain up to 2000 ppm, while canned mango pulp is limited to 100 ppm. Food processors must source only food grade material that meets the purity specifications above, and they should request halal or kosher certification if exporting to Middle Eastern or other markets.
Beyond preservation, sodium metabisulfite acts as an antioxidant in seafood processing, preventing black spot formation on shrimp—a major Indian export. It also serves as a dough conditioner in biscuit manufacturing, improving extensibility. A trustworthy sodium metabisulfite supplier in India should be able to provide documentation that traces each batch from production to delivery, supporting your own FSSAI compliance audits.
Across India, as new sewage treatment plants (STPs) and drinking water facilities come online, the need for efficient dechlorination has skyrocketed. Sodium metabisulfite neutralizes chlorine and chloramine instantly via a redox reaction, and the stoichiometric dose is approximately 1.34 mg of Na2S2O5 per 1 mg of chlorine. For a plant handling 50 million liters per day with a residual chlorine of 2 mg/L, that translates to around 134 kg of product daily. Indian plant engineers favor the dry powder because it can be stored in bulk silos and fed by gravimetric feeders, reducing operator exposure compared to liquid bisulfite solutions.
India’s gold mines, particularly those in the Hutti-Maski greenstone belt and the expanding operations in Jharkhand, rely on cyanide extraction. After leaching, the tailings must be treated to destroy residual free cyanide and metal-cyanide complexes. Sodium metabisulfite with a catalyst like copper sulfate is a proven air-SO2 process method, converting cyanide to less toxic cyanate. The reaction demands a consistent, high-purity product—impurities can reduce efficiency and increase treatment time. This is the very application where the purity of Hailei Chemical’s sodium metabisulfite delivers a measurable return on investment.
In textile processing, fabric bleached with hypochlorite carries residual chlorine that must be neutralized before dyeing, otherwise it causes uneven coloration. Sodium metabisulfite is the preferred anti-chlorine agent because it leaves no residue that could interfere with reactive dyes. Similarly, in the pulp and paper industry—particularly in mills across Maharashtra and Gujarat—it is used to eliminate excess chlorine after the bleaching stage, protecting paper quality and reducing AOX emissions into the environment. These applications require industrial grade material with low heavy metal content to avoid spotting on final products.
The decision between sodium bisulfite and sodium metabisulfite often hinges on logistics and dosage form. Sodium bisulfite is typically available as a 30–40% solution, which is convenient for plants with existing liquid chemical feeds but incurs higher shipping costs because you are transporting mostly water. Sodium metabisulfite, a dry powder, reduces freight cost per active kilogram by up to 60% and offers better storage stability—critical in the humid Indian climate, provided the bags remain sealed. Once dissolved, the chemistry is essentially the same: the metabisulfite hydrolyzes to bisulfite ions. For Indian buyers who value flexible inventory and lower inland logistics expenses, the powder form from an experienced sodium metabisulfite supplier in India is almost always the more economical long-term choice.
When you buy sodium metabisulfite from an international supplier, understanding the import flow is essential to avoid demurrage and detention charges. The cargo typically departs from major Chinese ports such as Qingdao or Shanghai and arrives at India’s west coast ports within 15–20 days. Upon arrival, the importer must file a Bill of Entry under Customs Tariff Heading 2832.20 for sulfites. Duty rates are generally 7.5% basic customs duty plus applicable IGST of 18%, though rates may vary under the India-ASEAN FTA or other trade policies.
Top tips for smooth importation:
A supplier well-versed in India shipping can provide CIF delivery to Mundra, Chennai, or ICD Delhi, and even help arrange last-mile transport to your facility. This is a hallmark of a true logistics-savvy sodium metabisulfite supplier in India.
The lowest per-ton price on a commercial invoice rarely translates to the lowest total cost. Consider these hidden factors:
When you partner with Hailei Chemical, you receive 98% pure sodium metabisulfite packed in heavy-duty 25 kg bags, fully palletized, with a 100% on-time documentation record. The slight premium over generic suppliers is quickly offset by lower operational risk and higher process stability—a value proposition appreciated by procurement managers across India.
Beyond the checklist earlier, perform these due diligence steps before placing an order:
Whether your operation involves uses of sodium metabisulfite in municipal water dechlorination, food preservation, gold mining cyanide destruction, or textile processing, the choice of supplier directly influences your product quality, regulatory compliance, and bottom line. A reliable sodium metabisulfite supplier in India goes beyond commodity brokering—they become a partner in your supply chain resilience. By insisting on documented purity, Indian standard compliance, intelligent logistics support, and transparent pricing, you turn a chemical purchase into a competitive advantage.
Hailei Chemical has decades of experience producing and exporting premium sodium metabisulfite to Indian buyers. Our team understands the nuances of FSSAI requirements, mining industry performance demands, and the logistics of delivering to any Indian port efficiently. We are ready to support your business with consistent quality and technical expertise.
Ready to discuss your sodium metabisulfite requirements? Request a quotation or contact our India-desk team for a personalized consultation. Explore our full product specifications at sodium metabisulfite product page.