HEDP Na, Hydroxyethylidene Diphosphonic Monosodium


HEDP·Na is the monosodium of hydroxyethylidene diphosphonic acid. It is an organophosphorus acid corrosion inhibitor. This HEDP monosodium salt can chelate with Fe, Cu, and Zn ions. It can dissolve the oxidized materials.

HEDP·Na has good scale and corrosion inhibition effects even under 250℃. It is stable under a high pH value. HEDP·Na is not easy to be hydrolyzed and decomposed under normal light and heat conditions. Its acid/alkaline and chloride oxidation tolerance are better than that of other organophosphonic acids.

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HEDP·Na structure formula


Item Index
Appearance Colorless or yellowish transparent liquid
Active content (HEDP), % 19.0-21.0
pH (1% water solution) 2.3-2.9
Density (20℃), g/cm3 1.11-1.21
Fe, mg/L 20 Max.


HEDP·Na can form six-ring chelating compounds with metal ions in water systems, Ca2+ in particular. This hydroxyethylidene diphosphonic has good scale inhibition effects and obvious dissolution threshold effects. When used with other water treatment agents, the synergistic effects are better.

HEDP·Na is suitable for acidic scale inhibitors and detergents. It also can be used for metal surface treatment.

HEDP·Na is used in circulating cool water systems, medium and low-pressure boiler, oil field water pipelines as scale and corrosion inhibitor in fields such as power plant, chemical industry, metallurgy, fertilizer, etc. In the light woven industry, this product is used as a detergent for metal and nonmetal. In the dyeing industry, this product is used as a peroxide s|tabilizer and dye-fixing agent; In non-cyanide electroplating, this product is used as a chelating agent.


When used as a scale inhibitor, the dosage 2-20mg/l is preferred, when used as a corrosion inhibitor, the dosage 20-100mg/l is preferred, when used as a cleaning agent, the dosage 1000-2000mg/l is preferred. Usually, HEDP·Na is used together with polycarboxylic acid.

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Safety Protection:

Acidity, Avoid contact with eye and skin. Once contacted, flush with water.


(1-hydroxyethylidene)bisphosphonic acid sodium salt, Sodium Etidronate.


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