I only have a moment to spend- here are a few tips from my experience:

Metal Removal:
  Ion Exchange- Set up one system to recover copper only and one to
claim "mixed-metals" (ie Sn,Pb,Cu). Most economical to do at "end of
pipe" (segregate streams with drain piping and collection tanks). Filtration
and pH adjustment are critical. Chelating/Complexing agents (EDTA,
thiourea etc.) can create problems depending on ion exchange resins
selected. These systems employ acid stripping to concentrate the metals
collected on the resin.

  Electrowin- Parallel plate electrowinning systems ("Retec" is a well
known brand) are then used to complete metal recovery. Recovered
metal is sold for scrap.

 RO- Only employ RO if it is very feasible economically (in other words, if
the metal or chemical being separated from the rinse is very expensive),
or if water purity going into a process is of maximum concern.

Chemical/Water Re-use in General- Make sure it is more economical to
re-use than to discharge. Be prepared to give total assurance that
products brought back to the process will not create scrap. Be sensitive
to process engineering concerns (chemical/water purity returning to the
process).

 Cooling Water-  Worthwhile if water costs are high. Closed loop cooling
systems generally do not employ water- glycol is used. Leak monitoring
would be critical so as not to contaminate process. Another option is to
supplement rinses with water discharged from cooling lines- sort of dual
use.

Hope this helps,
Ted Myers
Process Eng
Johnson Matthey Semiconductor Packages, Inc.
Chippewa Falls, Wisconsin  USA

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