Actually, if the Sigma Mercer system referred to below is Liquid Ion
Exchange then the conclusions reached below are correct. The LIX equipment
is expensive, but there should be an acceptable R.O.I. if sufficient
quantities are generated.
Bob Dube
-----Original Message-----
From: Paul Klasek <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Tuesday, November 23, 1999 10:11 PM
Subject: Re: [TN] Ammoniacal Etchant
>Well, Geoff, below 's your answer . If you'd need more details,
>let us know .
>
>Thanks Rudy ; boiling in lime sounds top application to me .
>Nice no residue method indeed
>
>paul
>
>-----Original Message-----
>From: [log in to unmask] [mailto:[log in to unmask]]
>Sent: Wednesday, 24 November 1999 12:57
>To: [log in to unmask]
>Subject: Re: [TN] Ammoniacal Etchant
>
>
>Thanks for the compliment, this will be fun.
>
>To be specific, to "neutralize" usually means to adjust pH to make it
legal,
>
>or non-harmful. The pH of spent etchant is usually between 8.0 and 9.0,
>making it perfectly legal in even the US.
>
>The problem is the HUGE contained metal content, that is heavily chelated
to
>
>keep it in solution.
>
>To cut to the chase, you do not want to try to do remove this metal
>yourself.
> Yes, you can do it, but, you do not want to, unless you use the
Sigma-Mecer
>
>system, which is very costly, unless you are large enough to amortize the
>cost over a very large volume of etchant per day. (I figure you do not
want
>
>to consider a Sigma-Mecer system unless you generate 55 gallons, around 200
>liters, per day, but that is a guess).
>
>Otherwise to get rid of the Copper, you either have to use expensive
>precipitant, or dangerous Sulfides, and filter filter filter filter
>filter...and wind up with vast amount of hazardous sludge.
>
>Or, you can boil off the ammonia by adding caustic...no no no, just
>kidding....
>
>Don't do it yourself, unless you use the Sigma-Mecer system, it is a
>nightmare, even for the folks who are in the reclaim business, they earn
>their money. You really do not want to consider this on a small scale.
>
>What I would suggest, as an alternate, is to consider trying to make PCB's
>differently, using Cupric, plus panel plate, plus tent and etch...the
Cupric
>
>is a helluva lot easier to deal with, and often you can find somebody who
>wants to buy spent etchant from you to use for the contained copper salts.
>
>Best,
>
>Rudy Sedlak
>RD Chemical Company
>
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