plating, anodizing, & finishing Q&As since 1989
Converting from Cyanide to Alkaline base on Zinc Plating
I'm in an industrial training, So the company want me to make an idea belong how to change the Cyanide that are using in Zinc Plating convert to Alkaline base?Shah
Ed. note: Full name and city, please, Shah.
If you are presently using an cyanide containing zinc bath you are using and ALKALINE CYANIDE bath. If you want to explore a non cyanide alkaline bath these are widely used. However, it is generally not feasible to convert [do a sliding conversion] from cyanide to non cyanide because of the extended time required until the cyanide is completely consumed in the process.Gene Packman
process supplier - Great Neck, New York
First of two simultaneous responses -- 2005
Mr Packman, above, is 100% absolutely correct. I expess the same thing this way: If you slide you will create more cyanide bearing sludge to haul away than if you just waste treat the whole CN bath and start from scratch with the Caustic and ZInc. I learned that years ago while involved in changing over a 40 000 gallon zinc solution.
Robert H Probert
Robert H Probert Technical Services
Garner, North Carolina
Second of two simultaneous responses -- 2005
To switch from cyanide to cyanide free plating..
1) plate with MS anodes , stop adds of cyanide and drop zinc and metal to low values.
Maintain caustic at 70 to 75.
When the zinc and cyanide levels fall to 7 gms per liter or so the bath will not plate well. It will stop working at the low values.
Destroy cyanide using Sod Hypochlorite.
Use the remaining solution as a soak cleaner off line.
Make up a new bath of alkaline cyanide free zinc using proprietary systems from proven suppliers.
Asif Nurie [deceased]
- New Delhi, India
With deep regret we sadly advise that Asif passed away on Jan 24, 2016
You can find some useful information on website "pfonline" in section "articles" in article #049702, or Gooogle it with text string "anatomy of a conversion"
Maybe this can be a little bit helpful.
- Kranj, Slovenija (EU)
Indeed it is helpful, Dimitrij, as yet another example of replacing cyanide with non-cyanide outright, with no attempt at a sliding conversion.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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