HEDP 60 — Etidronic Acid Scale & Corrosion Inhibitor
Also known as: Etidronic acid, 1-Hydroxyethylidene-1,1-diphosphonic acid, HEDPA, Hydroxyethylidene diphosphonic acid, ZEELCHEM 101
1-Hydroxyethylidene-1,1-diphosphonic acid (HEDP 60) — the most widely used organophosphonate for threshold scale inhibition, corrosion control and metal-ion chelation.
- 60% active, Ca sequestration 525 mg/g
- Excellent scale and corrosion inhibition
- Chelates Fe, Cu, Zn, Ca, Mg
- Stable at high pH and temperature
What is HEDP?
HEDP (etidronic acid, CAS 2809-21-4) is an organophosphonate that inhibits calcium carbonate scale, controls corrosion and chelates iron, copper and zinc. It is the most widely used phosphonate in cooling-tower, boiler and oilfield water treatment. ZEELCHEM 101 is HEDP 60% with 525 mg/g calcium sequestration.
HEDP key facts and price
| Product | HEDP — ZEELCHEM™ 101 |
|---|---|
| Chemical name | (1-Hydroxyethane-1,1-diyl)bis(phosphonic acid) |
| Full form | HEDP — 1-Hydroxyethylidene-1,1-diphosphonic acid |
| Also known as | Etidronic acid, 1-Hydroxyethylidene-1,1-diphosphonic acid, HEDPA, Hydroxyethylidene diphosphonic acid |
| CAS number | 2809-21-4 |
| Molecular formula | C₂H₈O₇P₂ |
| Molecular weight | 206.03 g/mol |
| Grade | Active content (HEDP) %: 60.0 |
| Appearance | Colourless to light-yellow transparent liquid |
| Category | Phosphonates |
| Pack sizes | 65 Kg Carboy |
| Price | ₹10,725 for 65 Kg Carboy (₹165 per kg) + GST |
| Minimum order | 30 kg |
| Shelf life | 24 months in sealed containers |
| Delivery | 5–7 days across India; 10–12 days to remote areas |
| Documents | TDS, MSDS/SDS, batch COA, GST invoice |
| Supplier | ZEEL Product (ZEELCHEM™), Vadodara, Gujarat, India · ISO 9001:2015, 14001:2015, 22000:2018 |
HEDP overview
ZEELCHEM™ 101 is a 60% HEDP solution with a calcium sequestration value of 525 mg/g. It forms stable complexes with Fe, Cu, Zn, Ca and Mg ions, dissolves existing oxide films and inhibits carbonate scale at very low dose.
HEDP remains stable at high pH and temperature, which makes it suitable for cooling water, oilfield water and low-pressure boilers. It is also used as a peroxide stabiliser and dye-fixing agent in textiles and as a chelant in cyanide-free electroplating.
How HEDP works
At sub-stoichiometric dose HEDP adsorbs on growing carbonate crystals (threshold inhibition). At higher dose it forms a thin protective complex film with iron and calcium on steel surfaces, reducing corrosion, and it chelates metal ions in solution.
HEDP specifications
| Appearance | Colourless to light-yellow transparent liquid |
|---|---|
| Active content (HEDP) % | 60.0 |
| Ca sequestration mg/g | 525.0 |
| Phosphorous acid (as PO₃³⁻) % | 1.0 max |
| Phosphoric acid (as PO₄³⁻) % | 0.6 max |
| Chloride (as Cl⁻) % | 0.01 max |
| pH (1% solution) | 2.0 max |
| Density (20 °C) g/cm³ | 1.43 – 1.47 |
| Fe ppm | 10.0 max |
| Acetic acid % | 0.5 max |
| CAS No. | 2809-21-4 |
Typical values. A certificate of analysis is issued for every batch; TDS and MSDS on request.
Applications and industries
- Cooling water and low-pressure boilers
- Oilfield water
- Textile detergent and dye-fixing
- Cyanide-free electroplating chelant
Industries we supply
- Cooling towers and chillers
- Low-pressure boilers
- Oilfield water
- Textile bleaching and dyeing
- Cyanide-free electroplating
- Detergents and cleaners
Dosage and dosing point
Compatibility
Blends well with PAA, MA/AA, AA/AMPS, zinc and molybdate. Can be degraded by high chlorine residuals — use PBTC where chlorine is high.
Doses depend on your water analysis and operating conditions — send them to us for a free recommendation.
Handling, storage and safety
Acidic liquid: causes eye and skin irritation. Wear chemical goggles, nitrile or PVC gloves and an apron; keep an eyewash nearby. Store in the original closed HDPE carboy, in shade, at 5–40 °C, away from strong alkalis and oxidisers. Do not store in mild-steel or aluminium containers. Rinse spills with plenty of water. pH of a 1% solution is below 2.
Shelf life: 24 months in sealed containers.
Packing and pan-India delivery
Packs: 65 Kg Carboy, sealed HDPE with batch label. We dispatch HEDP from Vadodara, Gujarat by road transport and courier, with door delivery or transport-godown delivery. Standard delivery is 5–7 days anywhere in India and 10–12 days to remote locations; freight is to-pay or quoted on the proforma.
Gujarat: Vadodara, Ahmedabad, Surat, Ankleshwar, Bharuch, Vapi, Rajkot, Gandhinagar, Halol, Dahej, Jamnagar, Morbi — dispatched direct from our Vadodara base.
Across India: Mumbai, Pune, Delhi NCR, Bengaluru, Hyderabad, Chennai, Kolkata, Jaipur, Indore, Nagpur, Lucknow, Ludhiana, Coimbatore, Visakhapatnam and every other district served by our transport and courier partners.
Why buy from ZEEL Product
- Direct from Vadodara — ZEELCHEM™ brand, supplied by ZEEL Product with no middle layer.
- ISO certified — ISO 9001:2015, ISO 14001:2015 and ISO 22000:2018.
- Batch COA with every order; TDS and MSDS on request.
- Listed prices per kg and per pack, with a GST invoice for input credit.
- Technical support — dosing advice from your water analysis, by phone or WhatsApp.
HEDP FAQ
What is HEDP used for?
HEDP is used as a scale and corrosion inhibitor in cooling water and boilers, as a chelating agent for metal ions and as a peroxide stabiliser in textile bleaching.
What packing is HEDP available in?
Standard 30 kg and 65 kg carboys; 270 kg HDPE drums on request.
What is the price of HEDP 60 in India?
ZEELCHEM 101 HEDP 60% is ₹165 per kg — ₹10,725 for a 65 kg carboy, plus GST and freight.
What is the CAS number of HEDP?
The CAS number of HEDP (etidronic acid) is 2809-21-4; its formula is C₂H₈O₇P₂.
HEDP or ATMP — which is better?
ATMP is more economical for calcium carbonate control; HEDP gives better corrosion inhibition and chelation and is more stable at high temperature. Many programmes use both.
Is HEDP safe for drinking water?
HEDP is an industrial water-treatment chemical, not a drinking-water additive. Use it only in cooling, boiler and process water.
What is the price of HEDP per kg?
ZEELCHEM HEDP is listed at ₹165 per kg. The 65 Kg Carboy pack costs ₹10,725 plus 18% GST; freight is extra. Bulk buyers can ask for special pricing.
What is the full form of HEDP?
HEDP stands for 1-Hydroxyethylidene-1,1-diphosphonic acid.
Do you deliver HEDP outside Gujarat?
Yes. We ship HEDP from Vadodara to every state in India by road transport or courier — usually 5–7 days, and 10–12 days for remote locations.
What documents come with HEDP?
Every batch ships with a certificate of analysis and GST invoice. TDS and MSDS/SDS are available on request before you order.
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Technical content reviewed by the ZEEL Product technical team · Last updated 22 October 2026