Mix-Up 101

Q: One of our operators used nitric acid to adjust the pH of our nickel plating solution. Is there any way that we can salvage this solution or do we have to dump the tank and make up a new tank? S. E.

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A: I have been asked this question in a number of times in the last five or six years. I can’t say that we are having an epidemic of this problem, but it is a type of screw-up that should not occur. I am aware of one procedure that seems to work fairly often in removing much of the nitric acid from your nickel plating bath. Larry Durney mentions this process in one of his plating clinic columns. The method uses dummying of the plating bath using high current densities. The plating bath is kept at a relatively high temperature (165–170°F) and air agitated during the process. This will strip out the ammonia that is formed from the plating bath. A voltage of 8–10 volts and a small cathode are required. He reported good results using this procedure.

A more critical question is how did this happen in the first place? In my experience, things like this happen because communications are not what they should be. Perhaps a supervisor tells one of his operators to adjust the pH of the plating tank. Did he do this verbally and assume the operator understood what had to be done or did he do this by preparing an add slip and giving the add slip to the operator? Verbal instructions are fine in some situations but typically are not adequate if there are different languages spoken in the plating shop environment or if the operator/supervisor does not understand what the problem really is. Many of the problems that occur in plating as well as many other manufacturing operations are due to poor communications and documentation!