HOMEFAQsBOOKS JOBS: Help WantedSuggestions you are here: Hotline/Forum => Letter 11434
Copper plating solution analysis
I have problem with an analysis. Can anybody help me with how to test Rochelle salt in Copper plating solution?
Thanks,
Benigna Skorobogatiene
electrical components mfgr. - San Jose, California
First of three simultaneous responses --
The Metal Finishing Guidebook and Directory has a method. The subscription is worth the money for the Guidebook alone!
The basic method is MFGBD, comments are mine.
1. 5 ml sample (into erlenmeyer flask)
2. Add 25 ml 20% sulfuric acid. (fume hood!)
3. Filter the precipitate. Wash the flask and filter paper twice each with di water. Discard the precipitate (contains copper cyanide!)
4. Collect all the filtrate and boil 5 minutes.(fume hood!)
5. Titrate solution with 0.1 N potassium permanganate to pink endpoint. (this will fade, you need to get it to hold for 10-20 seconds)
Calculate: oz/gal KNaC4H4O6.4H2O = ml x 1.25 X N
Please respond if you notice any errors!
|
Bill Vins microwave & cable assemblies Mesa (what a place-a), Arizona |
Second of three simultaneous responses --
Pipette 5 ml Copper cyanide solution into a 250 ml beaker. In a hood, add 10 ml DI H2O and 5 ml HCl. Boil to destroy CN, but not to dryness. Cool, then add 2g Zn dust and allow to react for 30 minutes. Filter into a 250 ml flask and wash the paper. add 1g MgSO4, 10 ml 25% H2SO4, 50 ml DI water and exactly 50 ml of KMnO4. Heat to 89-90 C (do not boil) for about 30 minutes. Cool and add 10 ml 10% KI and titrate with .1M sodium thiosulfate and record volume used as V.
g/l Rochelle salt=(50-V)x0.938
|
James Totter, CEF - Tallahassee, Florida |
Third of three simultaneous responses --
This is a fairly straightforward analysis. Take 5 mL of sample by pipet and transger to a 100 mL Erlenmeyer flask. Add 25 mL 25% Sulfuric Acid to the flask. WARNING-this will evolve Hydrogen Cyanide! Perform in a fume hood. Filter. Wash the flask and filter paper twice with DI water. Boil the collected filtrate for 5 minutes. Allow to cool. Titrate with 0.1N KMnO4 to a pink endpoint.
Calculate Rochelle Salt Conc. (g/L) = mL used x 0.9375
Best of Luck
|
|
October 26, 2011
Can any of the published procedures be used in analyzing Rochelle Salts in a copper sulfate-rochelle salt plating solution?
Thank you.
- West Hartford, Connecticut, USA
October 31, 2011
Another method that does not need filtering is as follows.
Take 5 mls of plating solution into a flask.
Put in a fume cupboard, add 10 mls of H2SO4, Hydrogen Cyanide gas will go up the fume cupboard. Put the flask on a hot plate and heat until white SO2 fumes appear after the water has all boiled off. Remove from the hot plate, add 100 mls of water. Then add conc. ammonia until a deep blue colour just appears and remains. Add a few drops of 1-(2-Pyridylazo)-2-Naphthol (PAN) as indicator, then titrate to a green end point with 0.1 M EDTA. The colour may go back to purple a couple of times before you get the green end point to remain with addition of further EDTA. Cu g/l = Titre X 3.169.
- Isle of Man Great Britain
January 31, 2012 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread
Q. Hello folks,
My name is Bruno Pires and I am from Brazil. I work in a aeronautic company that supplies non destructive tests, chemical treatments and painting.
We are developing a small line for copper plating. I found some potentiometric bath analysis method, but we don't have this equipment.
I would like to know if there is another kind of bath analysis instead of potentiometric method, for example by titration and color change.
Bath composition:
Caustic Soda: 13,7 g/l
Sodium Cyanide: 4,7 g/l
Copper Cyanide: 37 g/l
Rochelle Salt: 49,8 g/l
Temperature: 50 - 60 ‰³°
- Sao Jose dos Campos, Sao Paulo, Brazil
February 3, 2012
Hi Bruno,
There are some really useful volumetric methods in this publication by Charles Rosenstein and Stanley Hirsch. You will find most of what you are looking for plus a lot more!
www.clarksonlab.com/caps.pdf
Chemist - Poole, Dorset