| HS Code | 840786 |
| Product Name | NTA 3Na |
| Chemical Name | Nitrilotriacetic acid trisodium salt |
| Synonyms | Trisodium nitrilotriacetate; NTA-3Na; Trisodium NTA |
| Cas Number | 5064-31-3 |
| Einecs Number | 225-768-6 |
| Molecular Formula | C6H6NNa3O6 |
| Molecular Weight | 257.08 g/mol |
| Appearance | White crystalline powder or granules |
| Odor | Odorless |
| Assay | ≥98% |
| Ph | 10.5-11.5 (1% aqueous solution) |
| Water Solubility | Highly soluble in water; approximately 600 g/L at 20°C |
| Solubility In Organic Solvents | Slightly soluble or insoluble |
| Density | 1.7 g/cm³ |
| Bulk Density | 0.6-1.0 g/cm³ |
| Melting Point | >300°C (decomposes) |
| Chelating Agent Type | Aminopolycarboxylate chelating agent |
| Ionic Form | Anionic trisodium salt |
| Storage Conditions | Store in a cool, dry, well-ventilated area in a tightly closed container |
| Hazard Classification | Irritant |
As an accredited NTA 3Na factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | NTA 3Na is supplied in 25 kg moisture-resistant, woven polypropylene sacks with inner polyethylene liners for industrial handling and storage. |
| Container Loading (20′ FCL) | NTA 3Na chemical is loaded in palletized bags into a clean, dry 20-foot FCL container for secure export shipment. |
| Shipping | Shipping description for NTA 3Na (trisodium nitrilotriacetate): Not regulated as dangerous goods by DOT, IMDG, or IATA. No UN number, hazard class, packing group, or labels required. Transport in sealed, labeled containers; protect from moisture, dust, and contamination. Verify current SDS and local regulations before shipment. |
| Storage | Store NTA 3Na in a cool, dry, well-ventilated area away from direct sunlight. Keep containers tightly closed and properly labeled. Protect from moisture and incompatible materials such as strong oxidizers and acids. Avoid dust generation and use secondary containment where possible. Do not store near food, feed, or drinking water. Follow local regulations and SDS recommendations. |
| Shelf Life | NTA 3Na is stable for approximately 2 years when stored sealed in a cool, dry place, away from moisture and incompatible materials. |
In household zero-phosphate laundry powders and institutional laundry detergents, trisodium nitrilotriacetate is incorporated as a builder/co-builder at 1.0–5.0 wt% in conventional powders and at 5–15 wt% in concentrated automatic dishwasher tablets, with higher loadings reserved for low-temperature wash programmes where calcium binding must occur before the wash liquor reaches 40 °C. The substance is dosed into the crutcher slurry after neutralisation of acid precursors and before zeolite hydration, typically at pH 9.5–11.0 and temperature 60–80 °C, to sequester Ca²⁺ and Mg²⁺ from hard water and to suppress calcium carbonate deposition on spray-drying tower walls. In spray-drying operations the slurry is atomised through pressure nozzles at inlet air temperature 250–350 °C and outlet powder moisture is kept below 12%; NTA 3Na levels above 5.0 wt% can raise crutcher slurry viscosity above 1500 mPa·s at 25 °C, increasing pump energy and reducing nozzle flow consistency, a processing threshold observed on single-stage spray towers with rotary atomisers. Compliance for detergents marketed in the European Economic Area is recorded under Regulation (EC) No 648/2004, Article 4 and Annex III, with ready biodegradability measured according to OECD 301E and ultimate aerobic biodegradability according to ISO 7827; in North America, detergent formulation effluents are subject to 40 CFR Part 417 manufacturing effluent guideline limitations. In institutional laundry operations using continuous batch washers, NTA 3Na is additionally combined with sodium citrate and polycarboxylates to reduce ash build-up on linen and to suppress iron staining from corroded steam condensate; liquid I&I detergents maintain the chelant at 2–7 wt% of total formulation and dose it through diaphragm pumps at wash zone temperatures between 60–85 °C. Terminal finished product types include household laundry powders, monodose laundry tablets, automatic dishwasher tablets, oxygen bleach boosters, and institutional laundry sachets for continuous batch washers, in which the chelating agent is protected by alkaline granular matrices at pH above 9.5 to maintain storage stability.
Continuous pad–steam bleaching of woven cotton and cotton-blend fabrics operates within a narrow stabiliser demand window because Fe³⁺ and Mn²⁺ ions leached from raw fibre, water mains and equipment surfaces catalyse peroxide decomposition through Fenton-type pathways. In this process, NTA 3Na is added to the pad bath at 0.5–2.0 g/L, with the upper limit determined by a measurable reduction in bleaching efficiency above 2.0 g/L due to over-sequestration of Ca²⁺ that weakens the fibre-swelling electrolyte environment. The pad bath is prepared at 35–50 mL/L of hydrogen peroxide 50%, 8–20 g/L sodium hydroxide, and 0.5–2.0 g/L NTA 3Na, adjusted to pH 10.8–11.3; the fabric is padded on a two-roll padder at 2.5–4.0 kg/cm² nip pressure to achieve 80–100% wet pickup, then steamed in a horizontal or roller-bed steamer at 100–102 °C for 20–45 min. After steaming, the fabric is rinsed at 85–95 °C in a hot counterflow washing range that reduces residual peroxide and saponified waxes before drying on cylinder dryers at 120–140 °C. In cold pad batch preparation lines, NTA 3Na at 0.2–0.8 g/L is also added to the alkali bath to prevent silicate precipitation and to maintain peroxide stability during batching times of 12–24 h; the batch is wrapped in polyethylene film and rotated slowly at 8–12 rpm to avoid liquor segregation. Compliance documentation for European textile mills is generally aligned with the EU Ecolabel for textile products, Commission Decision (EU) 2017/1392, and ZDHC MRSL V3.1, while finished fabric is tested to ISO 105-C06 for laundering colour fastness and ISO 105-X12 for rubbing fastness. Terminal finished product types include bleached woven sheeting for hospital linen, reactive-dyed cotton knitgoods, denim preparation for garment dyeing, and medical gauze requiring extractable calcium below 50 mg/kg.
During cathodic cleaning of steel and brass substrates, alkaline electrocleaner concentrates are formulated with NTA 3Na at 10–40 g/L in the working bath to chelate calcium, iron and copper drag-in from steel and brass substrates. The bath operates at 65–80 °C and 3–12 A/dm² in either anodic or cathodic polarity, with pH maintained above 12.0; below 10 g/L NTA 3Na, iron hydroxide sludge accumulates on tank walls and immersion heaters within 8–16 operating hours, while above 40 g/L the bath viscosity and conductivity shift raises rectifier voltage demand from approximately 6 V to 9 V on conventional immersion tanks with copper bus bars. The downstream process is sequential: soak alkaline cleaning, secondary electroclean, triple counterflow rinse, acid activation in 5–10 vol% hydrochloric acid, and electroplating. Compliance in plating shops is anchored to ASTM B322-20 for cleaning of metals prior to electroplating, and finished articles for electrical and electronic equipment are expected to conform to EU RoHS Directive 2011/65/EU substance restrictions. Terminal product types include zinc-nickel coated automotive fasteners, copper-plated printed circuit board base materials, and electroplated hydraulic fittings.
Electroless copper deposition on glass-epoxy laminates uses NTA 3Na at 5–20 g/L as a co-complexing agent alongside EDTA or sodium potassium tartrate in the copper complex system. The working bath is maintained at 30–38 °C, pH 12.0–12.8, with continuous air agitation at 0.5–1.5 m³/h·m² of bath surface and filtration through 5 µm polypropylene cartridges. At NTA 3Na concentrations above 20 g/L, the deposition rate falls below 0.8 µm/h and through-hole backlight coverage deteriorates in horizontal conveyorised lines, as monitored by IPC-TM-650 backlight and deposit thickness procedures. The bath chemistry is replenished by continuous additions based on copper consumption and pH drift, with a working turnover of 1.0–1.5 bath volumes per week. Terminal product types include through-hole plated printed circuit boards, flexible circuit base films where adhesion promotion is performed by direct metallisation, and metal-clad laminates for automotive interior electronics.
| Metal ion | NTA 3Na log K₁ at 25 °C, 0.1 M ionic strength | Application consequence |
|---|---|---|
| Fe³⁺ | 15.87 | Peroxide stabilisation and electrocleaner iron control |
| Cu²⁺ | 12.96 | Electroless copper bath complexation |
| Zn²⁺ | 10.67 | Alkaline electrocleaner zincate control |
| Ca²⁺ | 6.41 | Detergent hard-water sequestration |
| Mg²⁺ | 5.41 | Cooling water scale inhibition |
Mechanical pulp and deinked pulp furnishes processed under alkaline hydrogen peroxide require a chelation stage to remove Fe³⁺, Mn²⁺ and Cu²⁺ that would otherwise cause peroxide decomposition and brightness reversion. NTA 3Na is dosed at 0.1–0.5% on oven-dry pulp in the chelation stage, and at 0.2–1.0 kg/t pulp as a stabiliser in the peroxide stage, depending on total manganese content above 10 mg/kg pulp. The downstream production process for deinked pulp involves medium-consistency pulping at 8–12% stock consistency, chelation at pH 5.0–6.5 and 60–80 °C for 30–60 min, followed by hydrogen peroxide brightening at 10–15% consistency, pH 10.5–11.5, temperature 80–95 °C, and residence 60–120 min. NTA 3Na must not be pre-mixed with cationic retention aids or alum at low pH, because aluminium-NTA precipitates can form and foul chest agitators and machine screens. Compliance for the mills is documented under the Best Available Techniques Reference Document for the Production of Pulp, Paper and Board issued under the EU Industrial Emissions Directive 2010/75/EU, and final products seeking the EU Ecolabel for tissue paper must meet Commission Decision (EU) 2019/70 chemical restrictions; pulp quality is verified by ISO 302:2004 kappa number and ISO 2470-1:2016 diffuse blue reflectance factor. Terminal finished product types include tissue paper, newsprint, coated mechanical paper, and moulded fibre packaging.
For scale removal operations in low-pressure gas wells with coiled tubing access, NTA 3Na is included at 5–20 wt% in aqueous scale dissolver packages, buffered with ammonium citrate or formic acid to pH 5.5–7.0 to balance CaCO₃ dissolution and CaSO₄/BaSO₄ complexation. The fluid is circulated at 0.3–1.0 bbl/min through a 1.5-inch coiled tubing string with a jetting nozzle, then shut in for 6–24 hours at bottomhole static temperatures up to 85 °C. Barium sulfate dissolution with NTA 3Na is kinetically slow below 60 °C; field workflows therefore hold circulating temperature above 70 °C and extend shut-in time to 48–72 h for sulfate scales. Published data for NTA 3Na thermal stability above 90 °C in downhole pressure cells is limited, so applications above that threshold require thermostability testing with formation water samples under 500–1500 psi backpressure before field mobilisation. The downstream process includes bullheading or coiled tubing injection, controlled flowback through a choke manifold, and pH neutralisation of spent fluid before disposal; H₂S presence requires operating limits under ISO 15156-1:2020 for cracking-resistant carbon steel and corrosion-resistant alloy couplings. Compliance testing for scale removal packages follows NACE TM0374-2016 for inhibitor screening and compatibility verification. Terminal finished product types include descaled production tubing in carbonate wells, sulfate-scaled saltwater disposal wells, and subsea flowlines treated by bullheading.
In open recirculating cooling water systems receiving makeup water with total hardness above 300 mg/L as CaCO₃, NTA 3Na is applied at 3–15 mg/L active concentration in the circulating water to inhibit calcium carbonate and calcium sulfate scale on heat-exchange surfaces. The product is injected continuously by metering pump into the cooling tower basin or return header, with conductivity-based blowdown control maintaining 4–8 cycles of concentration and a free NTA 3Na residual above 3 mg/L; below this residual, calcium carbonate deposition on warm surfaces is observed at heat flux values above 30 kW/m². The treatment boundary is pH > 9.0: NTA 3Na performs as a chelating scale inhibitor in alkaline recirculating water, but at pH 6.0 or below the fully protonated acid species dominates and chelation capacity is lost; it also must not be combined with aluminium-based coagulants in side-stream filtration because aluminium-NTA precipitates can foul sand filters. Compliance for industrial cooling water is determined by local discharge permits under the EU Industrial Emissions Directive 2010/75/EU, and in North America by state NPDES permits; NSF/ANSI/CAN 60 is not applicable unless potable water treatment is explicitly approved by the utility. Terminal product types include treated cooling water for HVAC chillers, process heat exchangers, and power plant auxiliary cooling loops.
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Trisodium nitrilotriacetate monohydrate, designated in detergent and metal-finishing batch records as NTA 3Na, is supplied as a white crystalline powder with the molecular formula N(CH2COONa)3·H2O. The anhydrous form is assigned CAS 5064-31-3 and molecular weight 257.06 g/mol; the monohydrate is commonly assigned CAS 18662-53-8 and molecular weight 275.10 g/mol. The compound functions as a tetradentate aminopolycarboxylate chelating agent, coordinating polyvalent metal ions through one nitrogen donor and three carboxylate oxygen donors. This structure produces five-membered chelate rings with calcium, magnesium, copper, iron, and zinc, but the stability constants are lower than those of the hexadentate ethylenediaminetetraacetic acid homologues. Consequently, NTA 3Na is selected where biodegradable chelation, lower molecular weight, and moderate metal affinity are required rather than maximum thermodynamic complex inertness.
A representative dry product specification includes an assay of 98.0–102.0% on an anhydrous basis by complexometric titration, a moisture content of ≤1.0% by Karl Fischer method based on ISO 760, and a 1% aqueous solution pH of 10.5–11.5 at 25 °C measured according to ISO 10523. The theoretical calcium binding capacity of the anhydrous product is 389 mg CaCO3/g, derived from a 1:1 molar reaction with calcium. For the monohydrate, this value decreases to 364 mg CaCO3/g, and commercial material is typically specified at ≥360 mg CaCO3/g when determined by potentiometric calcium titration. These values are stoichiometric; practical effectiveness in hard-water systems depends on pH, temperature, concentration of competing anions, and the oxidation state of transition metals.
Commercially available forms include anhydrous powder, monohydrate powder, and aqueous solutions around 40% solids. The monohydrate is preferred for dry blending in ribbon mixers because its loose water reduces dusting while maintaining flow through rotary airlock feeders. Bulk storage in unsealed supersacks at relative humidity above 60% may cause moisture uptake, bridging in screw feeders, and off-spec assay after prolonged storage.
In heavy-duty alkaline cleaning lines—spray washers, soak tanks, and bottle-washing machines operating with 1.5–3.0% NaOH at 70–85 °C—NTA 3Na is metered into the bath at 0.5–2.0 wt% of the working solution. The function is not only calcium sequestration but also prevention of calcium carbonate and calcium silicate deposition on nozzles and heating coils. At a process water hardness of 200–300 mg/L CaCO3, a molar ratio of NTA to total hardness above 1.2:1 is typically maintained. The operational boundary appears at pH values above 12.0, where hydroxyl competition reduces the effective calcium conditional stability constant; formulators then blend NTA 3Na with gluconate or phosphonate scale inhibitors. Feeding practice on production lines avoids dumping dry NTA into cool tanks below 10 °C because dissolution time extends and localized stratification can occur. Steam-jacketed recirculating loops with centrifugal pump educators are preferred for addition; final bath pH is adjusted with dilute acid after complete chelant dissolution to avoid pH overshoot.
| Property | NTA 3Na | EDTA-4Na | Sodium gluconate |
|---|---|---|---|
| Molecular weight, g/mol | 257.06 | 380.17 | 218.14 |
| Ca2+ stability constant, log K1 | 6.41 | 10.70 | 1.21 |
| Theoretical product mass to chelate 1.0 mmol Ca2+, mg | 257 | 380 | not defined by simple 1:1 stoichiometry |
| Typical pH, 1% solution | 10.5–11.5 | 10.7–11.7 | 6.5–7.5 |
| OECD 301B aerobic ready biodegradation | readily biodegradable | not readily biodegradable | readily biodegradable |
The data in the comparison table explain why NTA 3Na is not a direct drop-in substitute for EDTA-4Na in every formulation. To chelate an equal molar quantity of calcium, the required anhydrous NTA 3Na mass is about 68% of the EDTA-4Na mass because of the lower molecular weight. However, the lower calcium stability constant means that NTA is more sensitive to pH shifts and to competing ions such as carbonate. Sodium gluconate, despite its lower calcium affinity, is retained in high-pH systems for iron oxide dispersion and for aluminum dissolution in alkaline etching because its hydroxyl groups provide additional complexation modes.
Liquid laundry and industrial warewashing detergents replace sodium tripolyphosphate with NTA 3Na at concentrations of 0.3–2.0% in high-electrolyte systems. The processing issue in such materials is not chelation performance but phase stability: NTA salts increase the electrolyte activity of the continuous phase and can depress the cloud point of nonionic surfactant systems when nonionic content exceeds 15%; hydrotropes such as sodium xylene sulfonate are then required to maintain a clear single-phase product. In aerobic wastewater treatment, NTA 3Na is biodegradable under OECD 301B conditions, but anaerobic degradation in cold benthic sediments is slower. The use of NTA in household detergents has been restricted in some jurisdictions because of toxicological reviews. Formulation chemists should verify the current EU Detergent Regulation or U.S. EPA Safer Choice criteria before specifying the product for consumer retail lines.
In electroplating shops, NTA 3Na is used in alkaline electrocleaners and alkaline zinc plating baths to control hardness and transition-metal residuals. For rack zinc plating lines with bath volumes of 4000–8000 L, NTA 3Na is maintained at 5–15 g/L in alkaline zincate electrolytes, where it complexes iron and copper and prevents flocculation of zincate. The operational boundary is bath temperature above 60 °C, where prolonged residence time can lead to chelator oxidation at the anodes and accumulation of carbonates. Spent electrocleaner baths containing NTA should be treated by caustic precipitation for metals and aerobic biological polishing for chelant removal before discharge.
The calcium binding capacity of NTA 3Na is determined by complexometric titration against standard calcium solution using a calcium-selective electrode or a suitable indicator, because no single international standard defines this product-specific parameter. A validated in-house method based on ISO 9001 work instructions is common in bulk chemical receiving laboratories. The stoichiometric basis is the formation of a 1:1 complex between NTA and Ca2+. The theoretical maximum of 389 mg CaCO3/g for the anhydrous salt represents complete conversion of all NTA molecules to the calcium chelate; commercial shipments generally fall between 360 and 389 mg/g after moisture and assay correction. The finished product should therefore be sold and controlled against a chelation value specification, not a single molecular weight or pH claim.
| Parameter | Test method | Representative specification |
|---|---|---|
| Appearance | Visual | White crystalline powder, free-flowing |
| Assay, anhydrous basis | Complexometric titration | 98.0–102.0% |
| Moisture | ISO 760 | ≤1.0% |
| pH of 1% solution | ISO 10523 | 10.5–11.5 |
| Calcium chelation value | Potentiometric calcium titration | ≥360 mg CaCO3/g |
| Residue on 100-mesh sieve | ISO 3310 | ≤0.5% |
| Heavy metals as Pb | ISO 11885 | ≤10 mg/kg |
Specifications apply to a single production lot; incoming inspection on bulk storage silos should include moisture analysis because NTA 3Na monohydrate can release or absorb water under fluctuating warehouse humidity. Product stored in unsealed supersacks at relative humidity above 60% may bridge in screw feeders and produce off-spec assay after prolonged storage.
Textile bleach liquors containing hydrogen peroxide at 10–30 g/L and sodium hydroxide or soda ash at pH 10.5–11.5 require sequestering agents to prevent iron- and manganese-catalyzed peroxide decomposition that would otherwise reduce fabric whiteness. NTA 3Na is selected in this route at 0.3–1.0 g/L because it chelates released transition metals without the fiber-feeding problem encountered with sodium silicate stabilizers. At equal weight dosage, NTA 3Na provides a higher molar concentration of chelator than EDTA-4Na because its molecular weight is lower; however, its Fe3+ stability constant is lower. The process limitation is copper contamination: when dissolved copper exceeds 0.5 mg/L, additional stabilization with magnesium sulfate or an auxiliary polycarboxylate is required because NTA alone may not prevent localized peroxide decomposition at temperatures above 90 °C. Published data for this specific configuration is limited to mill-scale bath observations and does not identify a universal replacement ratio.
In oilfield scale control and wellbore cleanup, NTA 3Na is used as a carbonate scale dissolver in acidizing or neutral-wash formulations. In hydrochloric acid, the acid dissolves calcium carbonate, while NTA keeps dissolved calcium in solution after the local pH rises as the acid spends. The distinction from EDTA is significant for barium sulfate scale: NTA 3Na is not a suitable standalone inhibitor or dissolver for barium sulfate because the Ba–NTA complex stability is lower than the sulfate precipitate driving force. Phosphonate inhibitors and EDTA/DTPA-based dissolvers are applied for sulfate scales. Field data for NTA-only treatment of barium sulfate scale are limited, and laboratory compatibility tests with formation brine are required before pumping.
Low-temperature warewashing machines operating at 40–55 °C present a different chelation demand than high-temperature industrial spray washers. In these systems, calcium carbonate precipitation is kinetically slower, but protein and starch soils contribute suspended solids that can redeposit if the engineered polymer system fails. NTA 3Na at 0.2–0.8% provides hardness chelation while maintaining lower viscosity than high-dose citrate salts. The product is typically blended with acrylic acid–maleic acid copolymers to prevent soil suspension breakdown, especially when rinse water hardness exceeds 150 mg/L CaCO3. Processing equipment for dry granular detergent production—horizontal ploughshare mixers, rotary drum agglomerators, or fluidized-bed spray granulators—requires consistent NTA particle size; screen residue above 0.5% on a 100-mesh sieve may cause visible specking in final tablets.
The principal difference from phosphonates is NTA's function as a stoichiometric chelant rather than a threshold scale inhibitor. Phosphonates act at substoichiometric doses by disrupting crystal growth, whereas NTA must be dosed on a molar basis relative to hardness unless it is used in a blended system. Compared with sodium citrate, NTA 3Na offers stronger calcium binding and better heat stability in alkaline baths. Citrate salts have GRAS clearance under U.S. FDA 21 CFR 184.1751; NTA 3Na does not hold comparable food-contact clearance and is confined to industrial lines unless a specific regulatory review applies. In oxidative environments containing hypochlorite or strong bleach, NTA 3Na should not be premixed with chlorinated alkalis because oxidation can degrade the aminopolycarboxylate and reduce chelation capacity. The product is added separately after bleach dilution, and incompatible amine-based additives should be avoided where premature crosslinking or exothermic decomposition may occur.
