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Foaming from chrome suppressant
Q. The water we use for rinsing our chrome plated parts goes to an evaporator to allow us to evaporate off the water, we start the process at approx. 10-15 grams per litre of chrome,and stop the process when we reach around 250 g.p.litre. The problem we have is foaming in the tower and collection tank, this is caused by the suppressant we add to the chrome plating tanks,. this gets transferred into the evaporator with the chrome rinse water,we are trying to find a way to stop the foaming which slows down the evaporating process, does anyone have any answers?
A. You might try sending the solution feeding the evaporator through activated carbon. Unfortunately, if you remove the expensive foam suppressant, you will have to replenish it. LKLyle Kirman
consultant - Cleveland Heights, Ohio
A. Unfortunately, the additive is doing what it is intended to do, create a foam blanket. In the bath it keeps the mist down, which is good. But in your evaporation step, it slows the volume reduction, which is bad. That's a common problem with recycling and waste treatment operations - you're often trying to accomplish the reverse of what the process solution does while in service.
I can think of two things that might help. 1) Pass the rinse through a bed of a polymeric adsorbent, such as Amberlite XAD-4. This may remove the foaming agent. 2) Add a step where the rinse is downflowed through a tall, small diameter tank, and air sparged up through it. Then collect and remove the foam from the top, which will contain a much higher concentration of the foaming agent than the bulk solution. Then, pipe the rinse to evaporation.
I have never tried either of these treatments on a waste such as you describe, so you would have to do some bench scale tests to see if either would work.
Hope this is of some help. Good luck!
Consultant - The Bronx, New York
A. Firstly, why not try to recover more rinse waters before evaporation. That said,what do you do with the rinse water from the evaporator? If it is being concentrated for disposal, use a defoamer in the evaporator BUT do not do this if the water is being returned to the chrome tank. You may find it necessary to use a different type of evaporator,such as a "paddlewheel" instead of packing type.Gene Packman
process supplier - Great Neck, New York
Chrome Bath FoamingAugust 8, 2016 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread
Q. We recently replaced our chrome bath solution. Since start-up 3 weeks ago we have been struggling with excessive foam on the tanks resulting in Hydrogen pops. We are using a non-foaming mist suppressant but the foam is more that 10"-12" thick at times. What can we add to get the foam reduced? What could be the cause?Gerry Marchese
- Beamsville, Ontario, Canada
September 8, 2016
This problem easy to fix, try to turn down amps 50-100 amps in chrome before the bar or rack pick up.
finishing shop - Roseville, Michigan