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-----Adding an acid etch salt...what could happen in waste water treatment?
We were having a problem with parts that have been heat inducted to a rockwell hardness of around 80. It seems to be causing silicates to appear on our parts, causing poor plate appearance. We were thinking about adding an acid etch salt that contains hydrofluoric acid. I would like to know what affect on ph probes in waste water treatment systems would occur(in a 857gal tank). The concentration of hce acid 30%, concentration of acid etch salt is 8oz/gal-8%by volume.(this is what I have been told anyway) We have a 857 galon tank in wwt. The information given to me was a bit vague, so any suggestions on what you THINK the situation is , would be greatly appreciated. Thanks and have a good one.
James D. Browning- Oxford, Mississippi
1999
If you are flowing the rinse from this tank along with a lot of other rinses to a common waste sump or pretreatment chamber, such that the pH of the combined is above 4 -5, I wouldn't expect much problem with the probe. If it's going into an acid treatment chamber (like a chrome reduction) you might see some early degradation of the probe. If you are batch treating spent acid bath in a tank with a mounted probe, it will get eaten up really quick. In the latter case, you need to either remove the probe until most of the acidity is neutralized, or replace the glass probe with an antimony pH probe and controller.
Dave Wichern
Consultant - The Bronx, New York
1999
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