Ask the Expert Question-and-Answer Archive (TRI)
by Joelie Zak, Scientific Control Labs, Inc.
Lead Compounds Generated From Lead Anodes in Chromium Plating Process
Q. Are there any standard calculations I can use to determine the amount lead processed the lead anode during chromium plating? NMFRC says to multiply 1.56 for each pound of lead anodes replaced. How do you determine the amount of lead replaced? We dont change our lead anodes every year. Therefore, I need a calculation based on amount of chrome plating or amp hours, to determine the lead "used."
A. This situation is posing lots of problems for chromium platers who didnt
replace their anodes in 2001.
Unfortunately, there are no calculations for lead compounds being generated in
your bath based on amp-hrs. The anodes are also chemically attacked, so there is
not a way to estimate based on this or the amount of substrate plated.
The best suggestion I can give is to weigh a new lead anode and weigh one of the
anodes in your tank. Take the weight difference and divide it by the number of
days/years since it was last replaced. This will give you an estimate of how
much lead was "used" in the tank over a given period of time. From this data,
you can then extrapolate and estimate how much was used in 2001.
Another suggestion would be to contact your lead anode supplier and see if they
have any estimation on average rates of anode dissolution from chromium plating.