HEDP·Na4, Hydroxy Ethylidene Diphosphonic Tetrasodium


HEDP·Na4 is the tetrasodium salt of hydroxy ethylidene diphosphonic acid. This HEDP tetrasodium is a good scale inhibitor for calcium carbonate. HEDP·Na4 can be used in low-pressure boiler water systems, circulating water systems, industrial and municipal cleaning water systems, and swimming pools.

The solid HEDP·Na4 is a white powder, soluble in water, easily deliquescence, suitable for use in winter and freezing districts. It is a kind of organophorphonic acid scale and corrosion inhibitor. It can form a stable complex with Fe, Cu, and Zn ions, dissolve the oxides on a metal surface, and has a good scale and corrosion inhibition effect under 250℃.

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Structure Formula:

HEDP·Na4 structure formula


AppearanceColorless to yellowish transparent liquidWhite powder
Active content (HEDP), %20.3-21.756.0 Min.
Active content (HEDP·Na4), %29.0-31.079.9 Min.
pH (1% water solution)10.0-12.0 (as it)11.0-12.0
Density (20℃), g/cm31.26-1.36
Phosphoric acid (PO43-), %18.4-20.452.0 Min.
Fe, mg/L20.0 Max.35 Max.
Moisture, %15 Max.
Phosphorous Acid, %1.0 Max.
Colour, APHA50.0 Max.


HEDP·Na4 is widely used in circulating cool water systems, medium and low-pressure boilers, and oil field water pipelines as a scale and corrosion inhibitor in fields such as electric power, chemical industry, metallurgy, fertilizer, etc.

In the light woven industry, HEDP tetrasodium is used as a detergent for metal and nonmetal. In the dyeing industry, HEDP·Na4 is used as a peroxide stabilizer and dye-fixing agent; In non-cyanide electroplating, HEDP tetrasodium is used as a chelating agent.

Packing and Storage:

Liquid: 200L plastic drum, IBC(1000L), customers’ requirement.

200l plastic drum 1000l IBC

Solid: 25kg/bag, customers’ requirement. Storage for ten months in a shady room and dry place.

25kg paper bags

Safety Protection:

Weak acidity, avoid contact with the eyes and the skin. Once contacted, flush with water.


HEDP tetrasodium salt, Dequest 2016, Tetra-sodium hydroxyethyl diphosphonate.


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