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Specialty Chemistry Forums => Chemical Engineering Forum => Topic started by: tms9918 on October 24, 2020, 01:56:20 AM

Title: Removing zinc hydroxide without affecting chromium oxide
Post by: tms9918 on October 24, 2020, 01:56:20 AM

As by title, I would like to remove zinc hydroxide from oxidized plated screws.
I found that acetic acid dissolves the zinc hydroxide very nicely, but it completely removes the chromium oxide as well.  Is there something that dissolves the former but not the latter?

Title: Re: Removing zinc hydroxide without affecting chromium oxide
Post by: chenbeier on October 24, 2020, 03:24:21 AM

Try with sodium hydroxide, takes a wile. Any acid dissolves zink and chromium. Hydroxide attacks zinc but chromium in minor.

Title: Re: Removing zinc hydroxide without affecting chromium oxide
Post by: tms9918 on October 24, 2020, 03:55:21 AM

Thank you I will try!
By "a while", what order should I expect? minutes / hours / days?
Is 1 mol/L something reasonable?