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Is it okay to use NaOH to neutralize CitriSurf 2250?

2003

Hi,

I am a Chemical Engineering Student at UIC, and the company I work for wants to install a citric passivation line. I have gathered a large sum of information. The question I have is when using Stellar Solutions [a finishing.com supporting advertiser] Citrisurf 2250 can I neutralize the ph with just NaOH and will it be okay to dispose of the solution if the ph is with in the local and federal EPA standards. Also can the NaOH be used when your ph is to low to bring the solution to the correct ph or is their a special product you must only use, when using CitriSurf 2250.

Thank You,

Chris Kozka
- Schiller Park, Illinois, USA

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Chris Kozka asked about suitability of neutralizing an industrial solution before disposal.

The answer is that nobody can advise you properly on this without knowledge of the specific local laws and regulations. The best way to find these out is to call the wastewater authority in your area. In some cases, this treatment may be all right, however in other cases adding the NaOH to your process for disposal makes you legally a "hazardous waste treater" with many additional requirements and costs. The CitriSurf makers [Stellar Solutions [a finishing.com supporting advertiser]] do include a substantial amount of information on their Website and would probably be glad to help advise you on this situation. And they will also tell you to talk to your local regulators.

Paul Tibbals, P.E.
gas & electric
San Ramon, California, USA
(My opinions are not related to nor a statement of my employer's)
2003

You are dissolving metal into the product. citric acid is a wonderful complexing agent. Simple pH adjustment will not reduce the metal content to your local discharge requirements in 99+% of the cases. Precipitation/neutralization does not make you a waste treatment facility, it makes you a Haz Waste generator and you better do a lot of homework on that or some agency you never heard of will come visit you. Also, watch out for title 3 reporting. There are numerous interpretations and it changes yearly (or so it seams). This information is available to the world! You would not believe how many lawyers make a living by class action lawsuits for totally trivial things.

James Watts
- Navarre, Florida
2003

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You should probably contact Lee kremer at Stellar Solutions [a finishing.com supporting advertiser], who make Citrisurf. Another possible method of dealing with the solution, is to allow it to evaporate into dry crystal, which can be easily stored and transported to a waste facility. Then the problem of handling gallons of contaminated water, becomes handling far less volume in dry waste, and finding a venue that specializes in the destruction of such material.

My question is "why throw it away?". The passivation solution should have a very long life, given the necessary maintenance protocols are adhered to. The citric acid solution will be useful until you are seeing iron particles precipitating to the bottom of the solution, meaning that enough iron citrate is present to overcome the citric acid s' function to solubilize free iron from the surface of your parts and complex them into the solution.

I passivate ASTM F138 316 lvm surgical steel in my own proprietary citric acid solution which I will never dispose of, as it is unnecessary. I simply modify the solution as needed. Due to the nature of the alloy I passivate, there is very little free iron to solubilize, so bath maintenance is rarely required. If your requirements are more vigorous, then perhaps a tighter maintenance schedule will work without the problem of disposal.

Jeff Swayze
body jewelry - Kelowna, B.C., Canada
2003