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-----Chromium plating baths
1999
I am a graduate student at the University of Minnesota. I am writing a paper on Chromium Plating and have had trouble finding some information (both on the web and in the literature).
I will be grateful if you could help me out with the following information. The information does not need to be very authentic, good estimates will do.
1. What is the average size of a commercial chromium plating bath
(In Litres)
2. How much chromium salt do these commercial baths consume per day (In Kgs)
3. On an average how many times are the bath solutions changed per day
4. How many times can one use the bath solution.
Thanks.
Water Resources Science, University of Minnesota, St. Paul, Minnesota
1). There is probably no way to calculate the average when some plating tanks are thimble-sized and others are big enough to dip a Winnebago into, but about 500-gallons is pretty typical.
2). I'd have to defer to a real plater for an actual number. But it has been estimated that in automated decorative plating 90 percent of the chromium is dragged out rather than electroplated. And it depends on production rate, drainage time, whether automated or manual, decorative or functional. So if you wanted to say 50 pounds, I don't know who could argue with you.
3). The baths are virtually never changed, it's an equilibrium process where--as you said--chromic acid is replenished as it's used. There are some tramp contaminants that must be periodically removed, but their volume is only the tiniest fraction of the tank volume.
4). They are used for years or decades.

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