Dosage of 1-Hydroxy Ethylidene-1,1-Diphosphonic Acid (HEDP)

The dosage of 1-Hydroxy Ethylidene-1,1-Diphosphonic Acid (HEDP) depends on its specific role in a water treatment system. It is typically used as a scale inhibitor, corrosion inhibitor, or cleaning agent, each requiring a different concentration.

Primary Water Treatment Dosages

For industrial circulating cooling water, boiler water, and oilfield water systems, the recommended concentration ranges are as follows :

Application Role Recommended Dosage (active component)

Scale Inhibitor 1 – 10 mg/L

Corrosion Inhibitor 10 – 50 mg/L

Cleaning Agent 1000 – 2000 mg/L

These dosages refer to the active component of HEDP. It is commonly used in combination with polycarboxylic acid-type scale dispersants to achieve a synergistic effect.

Dosage in Specific Formulations

In compounded water treatment formulations, the actual concentration of HEDP can be lower. For example, one patent describes a formulation where HEDP is used at 4 mg/L alongside other inhibitors. Another source mentions a typical usage concentration of 5 – 7 mg/L for scale inhibition.

Important Notes

Overdosing Risk: Adding more than the recommended range can be counterproductive. For scale inhibition, exceeding a certain dosage may actually promote scaling.

Synergistic Use: HEDP is often blended with other agents like zinc salts, molybdates, or copolymers to enhance its performance.

Specific Applications: In some specialized roles, such as a solubilization factor for stannous salts in a concentrate, the final diluted concentration of HEDP may range from 0.1 to 25 ppm.