Original Date: 06/02/1997
Revision Date: 01/18/2007
Best Practice : Optimization of Plating Baths
Since 1990, Sharretts has been filtering its zinc-plating solution, using disposable cartridge filters as a way to prolong the lifespan of plating baths. Although filtration successfully increased the lifespan, the procedure generated spent cartridge filters as a hazardous waste. To eliminate this hazardous waste, Sharretts installed reusable filters which could be cleaned as needed. In two applications, the company has successfully implemented filter presses as replacements for the cartridge filters.
Sharretts has also increased the dwell times over its processing tanks prior to the plating baths. Increased dwell times reduce the contaminant amounts carried from the processing tanks to the plating baths; improve the process control and productivity of the entire line; and increase the lifespan of the plating baths.
In cases where plating baths are spent and need to be replaced, Sharretts uses an in-house reclaim system for tin and zinc solutions. The spent bath solution is reclaimed by pumping the solution into a vessel; treating it to separate the organics and contaminating metals (e.g., iron, copper, lead), and running the solution through a final filtration. The solution is then analyzed and returned to the plating baths. Electroless nickel baths are shipped to an off-site reclaimer. By using reclaim methods, Sharretts eliminates these plating baths from being disposed as hazardous waste or as influent to the in-plant waste water treatment system. Chemical treatment costs are minimized and the volume of sludge is reduced.
Through innovative improvements, Sharretts has optimized its plating baths. Benefits from these improvements include extending the lifespan of plating baths, reclaiming spent plating bath solution, minimizing spent plating baths as hazardous waste, and implementing reusable cartridge filters in conjunction with an in-process filtration system.
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