Home /
T.O.C.
FAQs
 
Good
Books
Ref.
Libr.
Advertise
Here
Help
Wanted
Current
Q&A's
Search 🔍
the Site
pub Where the world gathers for
plating, anodizing, & finishing Q&As since 1989





-----

Identification of an unknown gold solution





September 3, 2010

I am the Chemical Hygiene Officer at Norwich University, where I've worked for the past 4 years. We have an old bottle simply labeled "Gold Immersion Solution", and marked as poison on the back. The manufacturer's name is missing. Of course we do not have an MSDS, and none of the current professors seem to know about it. Searching the Internet I'm guessing it is either gold chloride or gold cyanide. Litmus paper initially indicated weak alkali before fading back to neutral. So cyanide is my primary suspect. I'd like to neutralize the solution's hazard, and hopefully precipitate out a few grams of metallic gold, before disposal. I am contemplating using a sodium hydroxide or lime solution to raise the pH, then adding calcium or sodium hypochlorite to oxidize the cyanide radical. Hopefully the gold will precipitate sometime during the process. Do you have any suggestions? Thank you.

Robert Stockett
Chemical Hygiene Officer - Northfield, Vermont, USA



September 9, 2010

dear sir ,
u first add sodium hydroxide and then zinc dust in this solution .that will precipitate cement silver and gold . wash that residue by hot water and treat with nitric acid to dissolve silver and to get brown coloured gold sponge.

Bhupesh Mulik
jewellery - Mumbai, India



September 23, 2010

Hello,

If you need to identify gold in an unknown solution, the most appropriate method is to carry out a microchemical test on a drop of solution.
Use Chromatography of the drop , eluent may be n-butanol/HCl 4N , ot Ethyl acetate/Ethanol (1/1) in nitric acid medium (add 1ml)
Gold follows the eluent
Use SnCl2 , p-dimethylaminobenzylidenrhodanine, or other reactive, to identify gold.

With time the gold spot becomes black.

Albert Cau
- Toulon, Var, France


none
finishing.com is made possible by ...
this text gets replaced with bannerText
spacer gets replaced with bannerImages

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:

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


About/Contact    -    Privacy Policy    -    ©1995-2023 finishing.com, Pine Beach, New Jersey, USA