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Author: Subject: Getting chromium compounds out of chromated metal?
valeg96
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smile.gif posted on 27-4-2014 at 06:30
Getting chromium compounds out of chromated metal?


Some time ago I tried the classic HCl+H2O2+[chromated-zincated-otherated steel] and got a vigorous reaction with the release of perchloric acid and other stuff, like chromic anhydride.

Now, is there a way to isolate any chromium compound out of that?
Is there any other way to remove chromium from a chromated metal piece?
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blogfast25
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[*] posted on 27-4-2014 at 10:17


Quote: Originally posted by valeg96  
[...] and got a vigorous reaction with the release of perchloric acid and other stuff, like chromic anhydride.



Perchloric acid as in HClO<sub>4</sub>? That strikes me as impossible.

'Chromic anhydride': as in CrO<sub>3</sub>? Again, unlikely to form in an aqueous solution. What's more, in acid conditions Cr(VI) is reduced by H<sub>2</sub>O<sub>2</sub> to Cr(III).

If recovering chromium from scrap metal is your goal, scrap stainless steel is a better feed stock, IMO. It contains a minimum of 10.5 w% of Cr (Wiki).

[Edited on 27-4-2014 by blogfast25]




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LanthanumK
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[*] posted on 30-4-2014 at 08:07


Chromated metal is only coated, so an insignificant amount of chromium is present.



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HgDinis25
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[*] posted on 30-4-2014 at 08:55


What do you mean by releasing? Did you worked your products all the way to Chromic Anhydride, for instance, or are you saing that they formed by the reaction between the steel and the HCl/H2O2?
AFAIK, it's impossible to produce CrO3 or even perchloric acid, in the conditions mentioned.
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