1-Hydroxyethylidene-1,1-diphosphonic acid, HEDP

Properties
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 dissolve oxides on metal surfaces. It can still play a good role in corrosion and scale inhibition at 250 ℃, remains stable at high pH, is not easily hydrolyzed, and is generally not easily decomposed under light and heat conditions. The acid, alkali, and chlorine oxidation resistance are better than other organic phosphonic acids (salts). It can form hexagonal chelates with metal ions, especially calcium ions, in water, thus exhibiting good scale inhibition effect and significant solubility limit effect. When used in combination with other water treatment agents, it shows ideal synergistic effect.

HEDP solid belongs to high-purity products and is suitable for harsh winter regions; Specially suitable for cleaning agents and daily chemical additives in the electronics industry.

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 textile industry, it can be used as a cleaning agent for metals and non metals, a peroxide stabilizer and fixing agent for the dyeing industry, a complexing agent for cyanide free electroplating industry, and a carrier for radioactive elements in the pharmaceutical industry.

Technical Data

Analysis	Index
Appearance	Colorless or pale yellow transparent liquid		White powdery solid
Active content( as HEDP) %,        ≥	50.0	60.0	90.0
Phosphorous acid(as PO33-) %,      ≤	2.0	2.0	0.80
Phosphoric acid( as PO43-)%,        ≤	0.8	0.8	0.50
Chloride (as Cl-） ppm,            ≤	200	100	100
PH(1% aqueous solution),          ≤	1.5	2.0	1.5-2.0
Density(20℃)g/cm³,              ≥	1.36	1.4	---
Ca Chelating Value mg/g,          ≥	450	500	---
Iron (Fe2+) ppm,                 ≤	20	10	5.0
Active content( as HEDP. H2O) %,    ≥	---	---	98.0