Aloha, fun & authoritative answers -- no cost, no passwords, no popups
(as an eBay Partner & Amazon Affiliate we earn from qualifying purchases)

Home /
T.O.C.
Fun
FAQs
Good
Books
Ref.
Libr.
Adver-
tise
Help
Wanted
Current
Q&A's
Site 🔍
Search
pub
Metal finishing Q&As since 1989


-----

Removing chloride from silver KCN plating bath




Q. I have a silver cyanide bath. I think high chloride is problem; I want to remove it. But I don't know how to remove Cl out of bath. Any help please? Thank you very much.

Tawan
chemist - Bangkok, Thailand
2004


A. Normally silver chloride is pretty insoluble and will precipitate as a white powder. I have never seen chloride added to a cyanide silver bath, so why do you think it is a problem? I am not sure whether the cyanide complex will be strong enough to prevent the precipitation of silver chloride. Perhaps you can give us more details of what you are doing and why you think chloride is a problem.

trevor crichton
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2004


A. Where did the chloride come from? I may be wrong but I know of no silver cyanide bath that uses chlorides. I would bet that you cut costs and made the bath using silver chloride instead of silver cyanide. You probably dissolved some silver in nitric and then salted out the silver chloride, of which you dissolved in cyanide to make your bath. Cheap and safe way to go. Too bad it doesn't work :-(
You should have tried it in a beaker [beakers on eBay or Amazon] before making up a big batch. I've never seen high chlorides in a Ag cyanide bath before, so I don't know how it would affect the deposit. It may have worked at first but died as the chlorides built up from silver additions. Maybe it never worked well. I would bet it's the latter.
If I've misjudged the situation, please forgive me. I just can't figure out any other way the chlorides got in there. If I am wrong, please let me know. Now you have a big problem. You have a bunch of silver tied up in a worthless bath. I know of no way to get rid of the chlorides. If it were me, I would plate out the silver on a passivated stainless steel sheet. Then, peel the silver and sell it. Make up the bath with the right chemicals.

I would advise not making your own silver cyanide, unless you have a super fume hood and someone already experienced in doing such things. HCN, which is released, is the prison gas chamber gas.

Chris Owen
Consultant - Houston, Texas
2004




(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

Finishing
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g,
& Software


About/Contact  -  Privacy Policy  -  ©1995-2024 finishing.com, Pine Beach, New Jersey, USA  -  about "affil links"