Where the
world gathers for metal finishing
Q&As since 1989


-----

Keep Rinse Waters Neutral

Dear Sirs.

We are having problems in keeping the PH of our degreasing and pickling rinse tanks neutral. We are running on 3 shifts and its very difficult for us to change this rinses on week days. We try to in put fresh water during working time but it seems that is not enough to keep the PH neutral.

My question is: What will happen if I interconnect these two rinsing tanks so one will neutralize the other? Will this be a good practice? What risks are we taking doing this?

Thanks for your help.

Juan Carlos Sanin
galvanizers - Medellin, Antioquia, Colombia
2004

---

Dear Juan,

We practice waste minimisation wherever possible and yes, we counterflow most rinse tanks. We use airlift pumps. The only problem we have encountered so far is oil coming to the surface in alkaline rinses once the acid pH becomes to low, but this is only the case in plants where the articles are very oily coming in. I hope this helps!

Best regards,

Trudy Kastner
electroplating service - Durban, KZN, South Africa
2004

---

Be careful your degreaser does not contain cyanides.

Khair Shishani
aircraft maintenance - Al Ain, UAE
2004