Question regarding the use of nitric acid (55% dilution). We are a small production shop that turns over around 50 pieces/day. We use a sulphuric acid pickle (10% dilution) followed by a nitric acid dip to remove the cuprous oxide that appears after soldering.
Over time this nitric acid bath becomes a deep blue color due to it becoming saturated with said cuprous oxides. At this point the time it takes for the acid to do it’s job gets lengthier and lengthier, but if I go to neutralize this acid I can tell it still has a lot of strength in it (due to the immense about of bubbling and vapors that occur when I pour it into a giant bucket of lime). I’m thinking the longer time needed is due to it being over saturated with cuprous oxides and it just can’t take much more.
My question is this, is it possible to remove the cuprous oxides from the nitric acid and then keep on using it? If so, would this return the nitric acid to its original strength and short time needed to remove the oxides? I remember reading something somewhere on here about using steel wool to soak up the copper that gets put into a pickle pot, would something like this work?
Appreciate any advice offered!