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Acid-free metal cleaning for wire production



I posted a message last week about the replacement of pickle liquor in a wire 
casing operation.  The article was in the Dec. 1966 issue of POLLUTION 
ENGINEERING magazine on page 47.  The equipment is a DynaPower 
ultrasound/electrolysis cleaner made by DynaMotive Technologies Corp. in 
Vancouver.  At the Nucor Wire Inc. plant the toxic solid output alone was down 
550 - 600 percent compared to conventional systems that clean metal with pickle 
acids.  The system creates chemical reactions by the electrolysis in a shallow 
bath of hot water that contains "harmless" dissolved salts.  DC electrical 
current passes through this aqueous electrolyte to the wire, repeatedly 
alternating the wire polarity from anodic to cathodic.  The wire's dwell tiem in 
the electrolysis bath is measured in seconds at the cleaning systems speed of 
250 - 300 ft./min.  This weakens the bond between surface scale and the metal 
underneath.  After cleaning in the electrolysis bath, the wire proceeds through 
a series of low-pressure water jets through which pass shore compression waves 
of ultrasound.  When these waves encounter debris loosened by electrolysis, they 
"literally blast it away."  The wire is then rinsed in clean water and dried 
with air jets.  The wire exits the system pH neutral which keeps it from 
oxidizing upon re-exposure to air.  Capital costs amounted to about $200,000 
installed.

This goes to show you that there is nothing offering zero pollution.  The 
wastewater will need to be treated to remove the metals from the wire.  There 
will be a sludge.  But we did get rid of the acid!!!  We are also probably using 
more energy to run this little system.

Jacksonville Naval Air Station went to zero discharge of water.  They are using 
hydrogen peroxide (requiring Process Safety requirements) to treat the water and 
have to evaporate the water and dispose of the salts as a hazardous waste.  They 
did achieve zero discharge of WATER.  Think about it.

Robert B. Pojasek, Ph.D.
Cambridge Environmental Inc.
58 Charles St.
Cambridge, MA 02141
(617) 225-0812
(617) 225-0813 (F)
http://www.CambridgeEnvironmental.com