Sodium Nitrite

Nitrite is an anodic passivating inhibitor: it oxidizes exposed iron at anodic sites into a thin protective oxide film that stops further electrochemical attack. The film must be complete to work, so a minimum residual — commonly in the 500-2000 ppm region for closed loops — has to be maintained and verified by regular testing; letting the residual drop too low risks localized pitting at unprotected spots.

Technical grade is used for corrosion inhibition, chemical synthesis and textile dyeing. Food grade meets tighter purity limits for use as a curing agent (E250) in meat processing, where dosage is strictly governed by the applicable food regulations. CHIMI ART supplies both grades at ≥ 98.5% NaNO₂, each with a certificate of analysis; state the intended use when ordering so the correct grade and documentation are provided.

Sodium nitrite is an oxidizing salt. Contact with acids liberates toxic nitrogen oxide fumes, and mixing with combustible or reducing materials creates a fire hazard. Store it in sealed bags in a dry, cool, ventilated area segregated from acids, organics and reducing agents — correctly stored it keeps for 24 months.

The residual is checked with a drop-count titration or test kit on a routine schedule, and always after make-up water additions, drain-downs or repairs, since dilution is the usual reason protection is lost. If the reading falls below the target maintained for the system, top up with fresh solution and retest once the circuit has fully mixed.

Sodium nitrite is supplied in 25 kg and 50 kg bags, with bulk quantities available for larger consumers. Every batch ships with a certificate of analysis, and TDS and SDS documents are available from the product page.

As the curing additive E 250 / INS 250 in meat, fish and some cheese products: it inhibits Clostridium botulinum, fixes the pink cured colour and contributes to flavour. It is strictly dose-limited — in the European Union the maximum added amount in general meat products was lowered to 80 mg/kg, expressed as NO₂ ion, from 9 October 2025 under Regulation (EU) 2023/2108 — so only food-grade material may be used, under the rules of the destination market.

NaNO₂, molar mass 69.00 g/mol. It is readily soluble in water — about 80 g per 100 mL at room temperature, more when warm — giving a mildly alkaline solution (pH 8–9 at 1 %). It is hygroscopic and cakes in humid air, which is why bags are kept sealed and dry.

Nitrite (NO₂⁻) is the reactive, reduced form; nitrate (NO₃⁻) is the fully oxidised, more stable salt. Nitrite is the active corrosion inhibitor and curing agent and the diazotisation reagent; nitrate is used where slow release of nitrite is wanted (some traditional cures), as a fertiliser and as an oxidiser. Nitrite is more toxic and is regulated more tightly — the two are not interchangeable in any application.

UN 1500, class 5.1 oxidising solid with a 6.1 toxic subsidiary risk, packing group III. Store it dry and sealed, segregated from acids, ammonium salts, reducing agents and combustibles; food-grade stock is kept under its own controls away from technical material. Correctly stored it keeps for 24 months.