Summary for iron chain pickling chemicals Discussion
Historical iron chain pickling likely involved more than just acid. In response to Jim Gossweiler’s question about a former plant’s “pickling room,” the answerer notes that plain steel chains would have been too rust-prone to ship, so the facility most likely also used zinc electroplating with chromate conversion coatings, and possibly cadmium, nickel, and other platings. Black oxide coatings may also have been used. Beyond pickling acids such as hydrochloric acid and sulfuric acid, the process likely included caustic cleaners and solvent cleaners such as TCA/TCE. The answerer adds that if the plant handled castings, forgings, or stainless steel chains, nitric acid and hydrofluoric acid may also have been used. The main caution is that it is hard to know the exact chemicals without knowing the product lines.
Q. I am working on a former industrial plant that manufactured “mechanical chains” from about 1950 to 1990. The plant had a “pickling room.” I would guess they used HCl and H2SO4, but what other chemicals might have they used during this period?
Jim Gossweiler
environmental consultant – Baltimore, Maryland, USA
A. Hi. I doubt that they would have shipped plain steel chains because they would be too rust-prone. So in addition to using acids, they most likely did zinc electroplating along with a chromate conversion coatings as a topcoat, and perhaps cadmium, and nickel, and other platings. They might have done black oxide coatings. They would have used caustic cleaners, and most likely solvent cleaners (TCA/TCE) as well. If any castings/forgings were involved, or if they offered stainless steel chains, they probably also used nitric acid and hydrofluoric acid.
It is very difficult even to guess even what product lines they offered, let alone what chemicals they would use. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
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December 2014