The authoritative public forum
  for Metal Finishing since 1989
-----

Flux regeneration plan

February 27, 2009

We are at the research stage to construct a flux regeneration plant for our facility.

I want to learn how much H2O2 addition should we make for each tonnes of material we immerse into the bath.

What is the addition rules for adjust the PH and also to precipitate iron and regenerate the flux ?
Thanks for the help.

Hakan Esen, Material Engineer(BSc.)
galvanizing plant manager - Bursa, Turkey

---

Sir:
If you are trying to make a CONTINUOUS flux purification machine, there is a single BIG PROBLEM. The best pH for flux solution for galvanizing is 4.2 (range 4.0 to 4.5). For the oxidation of iron (+2) green solution, to iron (+3) orange Fe(OH)3 solid, the pH MUST be 5 or higher. Thus while CONTINUOUSLY maintaining pH 5 or higher in the purification tank and removing iron, the flux flow back to the working flux tank is 5 or higher and then must be again lowered CONTINUOUSLY to operate properly.
There are some commercially available flux purification machines in the market place and some of these corrode badly with software failing, pumps quit132ting, pipes leaking, pH probes not working, etc. etc. Some have a filter press some have filters. I have not seen one working long term.
There are better ways to solve the bad flux problem.
Regards,

Dr. Thomas H. Cook
Galvanizing Consultant - Hot Springs, South Dakota, USA
March 4, 2009