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Ammoniacal Etching of Copper

Dear Sir,

I have a prospect who recovers clean nickel from scrap nickel plated with solder and/or copper using ammonium chloride and ammonia solution. The resultant waste is blue spent etchant 2 Cu (NH3) 4 C 12 which requires further treatment.

Preliminary jar tests require 50-60 ml 18% liquid PAC per 1 liter wastewater (after ten times dilution) in coagulation and sludge volume is approximately 70%.

We are also evaluating ferric chloride ⇦this on eBay or Amazon [affil links] and TMT 15 as coagulants.

Please advise any alternative to treat these concentrated etchant 3 m3/day to comply with statutory requirement.

Thank you.

C. B. TAN
- Kluang, Johor, Malaysia
2001