Hydroxyethylidene Diphosphonic Acid HEDP

Alias: Hydroxyethylidene diphosphonic acid, HEDPA, (1-Hydroxyethylidene)diphosphonic acid, 1-Hydroxyethylidene-1,1-diphosphonic acid

【CAS】 2809-21-4   Molecular formula C?H?O?P? Relative molecular mass: 206.02

I. Product Performance

HEDP is an organic phosphonic acid scale and corrosion inhibitor that can form stable complexes with various metal ions such as iron, copper, and zinc, and can dissolve oxides on metal surfaces. It remains effective in corrosion and scale inhibition at temperatures up to 250°C, is stable at high pH values, not easily hydrolyzed, and generally does not decompose under normal light and heat conditions. It exhibits better acid and alkali resistance, as well as chlorine oxidation resistance, compared to other organic phosphonic acids (salts). It can form six-membered ring chelates with metal ions in water, particularly calcium ions, thus providing excellent scale inhibition and a significant threshold effect. When compounded with other water treatment agents, it demonstrates ideal synergistic effects.

II. Quality standards comply with HG/T 26324-2010  

III. Applications

HEDP is widely used in industrial circulating cooling water systems such as power, chemical, metallurgical, and fertilizer industries, as well as for scale and corrosion inhibition in medium and low-pressure boilers, oilfield water injection, and oil pipelines. In the light and textile industries, it can be used as a cleaning agent for metals and non-metals, a stabilizer for peroxides and a color fixative in dyeing and bleaching industries, and a complexing agent in cyanide-free electroplating.

IV. Packaging and Storage

HEDP liquid is packaged in plastic drums, 30 kg or 250 kg per drum, or as required by the customer. Store in a cool, ventilated indoor area, protect from moisture, with a storage period of ten months.

V. Safety Precautions

HEDP is acidic and should be avoided from contact with eyes and skin. In case of splashing, rinse immediately with plenty of water.