Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Air Agitation of HCl Pickling Tanks
[editor appended this entry to this thread which already addresses it in lieu of spawning a duplicative thread]
Q. Hi everyone.
We are into acidic zinc electroplating
Our process starts with degreasing the material with a particular chemical kept for 6-7 mins
Then we take it to HCl acid with titration between 8-18 (35% HCl)
1. I want to know if I use air agitation in the HCl tank will it be beneficial for me?
After HCl we rinse it with water.
2. If I use air agitation in water will it be beneficial for me. If yes, how?
Then we dip the material into alkaline cleaner
3. If I use air agitation in the alkaline cleaner tank will it be beneficial?
I have each tank of around 5k ltr.
Thank you.
- Odisha, India
August 14, 2024
Ed. note: Many readers use their real names because they enjoy the camaraderie of being part of this community; they may be less likely to engage with those who won't.
A. Hi Shubham,
We added your inquiry to a thread where 6 experienced platers unanimously believe that adding air agitation to an HCl acid tank is a bad idea. But maybe eductors would be okay.
Air agitation in rinse tanks is almost always a good idea. Your plating tank should have air agitation, see thread 42671, "Air agitation for acid chloride zinc plating bath". For more info on designing an air agitation system, please see thread 40886, "Agitation air sizing and calculations for plating & anodizing".
Your alkaline cleaner should be an electrocleaner -- this generates lots of gas bubbles at both the anode and the cathode, such that air agitation would hardly be worth it anyway.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
⇩ Related postings, oldest first ⇩
Q. Dear All:
Happy New Year,
Is it available to use a compressed air for HCl pickling agitation to accelerate the pickling process?
What are the advantages and what are the disadvantages?
Thank you, and best regards,
- Cairo, Egypt
2007
A. Salah, Process Engineer - Syracuse, New York A. Poor idea. You will rust out every iron and steel part within 50 feet.Use a pump or a mixer. James Watts- Navarre, Florida A. Salah Geoff Smith Hampshire, England A. I would strongly recommend against using any form of air agitation with an HCl pickle, because of the considerable increase in fumes that would be generated from the process. HCl produces quite a lot of fumes already, and you don't want to make it any worse. Consider mechanical agitation instead. John Reid- Brisbane, Queensland, Australia |
A. Dear Salha
you can not use air agitation with any acids pickling tanks it is very dangers . you can use mechanical agitation for the work parts
best regards,
- Cairo, Egypt
A. The best option is to use eductor pumped agitation which uses a chemical resistant pump to push the acid through an arrangement of eductor nozzles to achieve the required agitation without using air and without the nasty fumes associated with air agitation.
Mohamed El-Sharkawy- Cairo, CA, Egypt
June 9, 2012
Ed. note: Thread 1820, "Eductor agitation benefits", goes into a little more detail on this, or readers can search the site for dozens of references to eductors.
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