Chemical Forums
General Forums => Generic Discussion => Topic started by: Lewis on October 09, 2019, 08:50:35 AM
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Hello,
I would like to know how to remove the black residue, that remains on the surface of carbon steel after rust removal by treatment with citric acid. Household-typical means and minimal abrasive action would be preferred, although the surface is pitted under the rusted areas.
Thanks,
Lewis
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If it is carbon steel, the black may be residual carbon - the citric acid would dissolve the metal but leave behind the carbon.
The carbon might be removable with hydrogen peroxide - you could either use hydrogen peroxide from the pharmacy, or use something like Clorox2, which has hydrogen peroxide mixed with surfactants.
If you test it on a small area, usually if the hydrogen peroxide is working you will see bubbles forming.