Sunday, 31 May 2015

EDTA Cleaning



Cleaning on the basis of EDTA, Demclean 94®

. The Demclean 94 ® cleaning solution is based on EDTA in pH neutral media. This approach eliminates, not only iron oxides, yet also light oil, grease as well as atmospheric contamination.

The rust (iron oxides) is dissolved with the formation of a strong iron-EDTA complex. This enables the pH to be enhanced after cleaning without the iron precipitating as ferric hydroxide. Then neutralization the steel is passivated by dosing sodium nitrite.

This implies that only one solution is needed for pickling and passivation with less water being released. The waste water released by this cleansing procedure could be treated by biological water purification modified for EDTA processing.

Advantages: pH neutral cleaning agent; passivation with the cleaning solution; less waste water; not corrosive for other metals; time saving.
Disadvantages: addition of chemicals during the passivation phase; unable to eliminate mill scale; limited capacity for dissolving iron.

 

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