I once asked my father, a research chemist, this question and the answer was too abstruse for me to fully understand. Not much surprise there. :-)
In short though, acidic pickling solutions are reducing agents. That is, they remove the oxides of the metal by combining with them to either change them to something that stays in solution or to strip the oxygen molecules from them and turn them back to their original unoxidized form. Or something like that. Like I said, too complex for me to really grasp. They gobble up oxides faster than they gobble up the un-oxidized metal.
10% sulfuric acid is one pickle formula. Sodium bisulfite is, if I remember correctly, sulfuric acid that is half-neutralized so it is safer to use and less aggressive. The half neutralizing also buffers it so it is less quick to deteriorate with use, I think. Hazy recollections of answers given thirty years ago when I asked Pop.
Rick,I once asked my
Rick,
I once asked my father, a research chemist, this question and the answer was too abstruse for me to fully understand. Not much surprise there. :-)
In short though, acidic pickling solutions are reducing agents. That is, they remove the oxides of the metal by combining with them to either change them to something that stays in solution or to strip the oxygen molecules from them and turn them back to their original unoxidized form. Or something like that. Like I said, too complex for me to really grasp. They gobble up oxides faster than they gobble up the un-oxidized metal.
10% sulfuric acid is one pickle formula. Sodium bisulfite is, if I remember correctly, sulfuric acid that is half-neutralized so it is safer to use and less aggressive. The half neutralizing also buffers it so it is less quick to deteriorate with use, I think. Hazy recollections of answers given thirty years ago when I asked Pop.