Thread 511/79
Alkaline copper plating and Rochelle Salt Issues
Q. How can I treat my alkaline copper batch which was contaminated with phospho copper?
RAFFY EUSEBIO- CAVITE, Philippines
July 21, 2024
publicly reply to RAFFY EUSEBIO
A. Hi Raffy,
As always, the fewer words in the question, the more abstract and difficult to answer.
I'm reading it that you are operating a rochelle salt copper cyanide plating bath, and it not plating properly in some respect, but someone accidentally added a small amount of pyrophosphate copper to it, so your assumption is that the phosphorous is the reason why ... but it is a home-brew so no advice is available from a supplier?
I do not have any actual experience with resolving this problem, and hopefully a reader will come along who does :-)
Meanwhile, activated carbon does exhibit the ability to remove phosphorous, simply due to its huge surface area. Aquariums use ferric oxide to remove trace amounts of phosphorous. It is probably not removable via ion exchange. Again though, phosphorous comes in many forms and variations, so your actual situation may be critical towards receiving proper advice.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
publicly reply to Ted Mooney
⇩ Related postings, oldest first ⇩
How to determine the rochelle salt ⇦ on eBay or Amazon [affil links] concentration of an alkaline copper plating bath
Oscar Villalobosplating shop employee - Guadalajara. jalisco, Mexico
February 6, 2009
publicly reply to Oscar Villalobos
The following is a method from page 105 of
Analysis of Electroplating and Related Solutions
[on
Amazon,
...
on AbeBooks affil links] by Parker and Langford (4th edition):
pipette
[pipettes on
eBay or
Amazon [affil links]
a 5 ml sample into a 250 ml beaker [beakers on
eBay
or
Amazon [affil links] and add 5 ml concentrated hydrochloric acid. Boil to destroy cyanides and drive off hydrochloric acid. Do not evaporate to dryness. Cool, add 2 grams zinc dust
⇦ on
eBay or
Amazon [affil links]
and allow to react for about 30 minutes stirring occasionally. Filter through a 41 or 31 paper and ash with water. To the filtrate in a 250 ml Phillips beader add 1 gram of manganese sulphate, 10 ml of 25% sulfuric acid and then exactly 50 ml of N/10 potassium permanganate
⇦ on
eBay or
Amazon [affil links] . Heat at 80-90 deg C, but do not boil for approx. 30 minutes. Coll to room temperature and add 3 grams of potassium iodide then titrate the liberated iodine with N/10 sodium thiosulphate
⇦ on
eBay
or
Amazon [affil links]
to the normal starch end point. The ml potassium permanganate minus the mls sodium thiosulphate gives the permanganate used in the oxidation since the two solutions are equiv.
ml N/10 KMnO4 x .9375 = g/l COOK.CHOH.CHOH.COONa.4H20
I wish for you to note that the above procedure, in my opinion should be performed under an adequate exhaust hood and that all proper safety precautions should be observed.
process supplier - Great Neck, New York
publicly reply to Gene Packman
See page 456 of the 2007 Metal Finishing Guidebook. The last analysis is for Rochelle salt (potassium-sodium tartrate).
Kurt Sammons- Inman, South Carolina
publicly reply to Kurt Sammons
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