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Waste Treatment of Copper Containing Sodium Persulfate Etchant Solutions

IP.com Disclosure Number: IPCOM000084450D
Original Publication Date: 1975-Nov-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Kuzma, R: AUTHOR [+4]

Abstract

Waste waters containing ammonium persulfate waste etchants can be treated as follows:

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

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Waste Treatment of Copper Containing Sodium Persulfate Etchant Solutions

Waste waters containing ammonium persulfate waste etchants can be treated as follows:

The spent sodium persulfate is collected and a weak reducing agent such as sodium metabisulfite is added at a controlled pH. This will reduce the sodium persulfate to sodium sulfate and generate sulfuric acid. A small amount of catalyst is added or alternatively the copper acts as the catalytic agent. The sodium sulfate produced is safe for subsequent discharge.

Subsequent to addition of the weak reducing agent, sodium hydroxide is added to adjust pH to 10 and precipitate copper hydroxide. After the precipitate settles, the effluent containing the sodium sulfate is decanted. The settled copper hydroxide (and oxide) is washed with deionized water several times and is available for conversion to copper sulfate by addition of sulfuric acid.

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