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Re: ECM assistance

The only alternative I have ever implemented
successfully for non-water rinsing after ECM
involved using the process chemistry as a rinse.
A separate container is set up where the parts are
rinsed in the acid eventually used to replenish
the ECM solution.  The parts were then water
rinsed basically as you described.  This
effectively captures a good percentage of the
contaminants, but rinsing with acid is really a
devilish process, mostly because of its viscosity
and worker safety, and this approach was only
retained for one part of the operation.  This was
several years ago, and I now think it was a poor
trade-off v. well-controlled water rinses, treated
using ion exchange before discharge.

BTW, all kinds of air blow-off approaches were
also evaluated, and all failed, mostly because of
poor productivity, but also worker safety.

----- Original Message -----
From: Judith Wlodarczyk <jwlodarc@connstep.org>
To: <p2tech@great-lakes.net>
Sent: Tuesday, July 27, 1999 10:23 AM
Subject: ECM assistance

> I have a client that uses an Electro-Chemical
Machining (ECM) process to
> manufacturer hypodermic needles, cannulae and
other specialty products.
> Currently, the product is removed from the ECM,
put into a small tub in bulk
> form and manually rinsed with water to remove
the chemical solution.  It is then
> put into a tumbling process and rinsed again.
Both rinse waters are disposed
> into a holding tank for evaporation.
> We would like to find a different way to remove
the chemical without introducing
> water into the process.  If we could remove it
without diluting with water, we
> can reuse the solution and keep the wastewater
stream cleaner.  The current
> process adds chromium levels in the wastewater
that are above the discharge
> limits, creating the necessity to evaporate.
The business is growing and
> quickly going to exceed evaporation
> We discussed putting the product into a spin
dryer and using centrifugal force,
> but are concerned that the chemical will destroy
the drum very quickly, unless
> we use a very costly stainless steel drum.
> Has anyone had success removing the chemical in
such a way as to not use water?
> Any ideas or experience would be most
> Thank you,
> Judy Wlodarczyk
> 185 Main Street, Suite 408
> New Britain, CT  06051
> 860-644-9718 (phone)
> 860-832-4620 (fax)
> jwlodarc@connstep.org

Juna Z. Snow
List Manager
Waste Management & Research Center