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HCL cleaning on Hot Dip Galvanizing Line

We have recently installed an enhanced cleaning (HCL)section to our hot dip galvanize line. Now, we are experiencing an increased amount of ferrous chloride / ferric chloride ⇦this on eBay or Amazon [affil links] crystals building up in our system. It is to the point that when we attempt to check acid concentration / Fe concentration, the acid "freezes" in the pipette [pipettes on eBay or Amazon [affil links] . Does anyone have a solution as to what we are experiencing?

Dan Lansberry
- Warren, Ohio, USA
2000

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2000

'Freezing' is happening due to the ratio hydrochloric acid/Iron at a certain temperature.

i.e. at 20 °C:

hydrochloric acid -iron = 100 g/l - 170 g/l

iron is freezing out (crystallizing)

hydrochloric acid - iron = 50 g/l - 170 g/l

iron is in solution

at 40 °C with a ratio 100/170 iron is not freezing out.

So I think you our around saturation with the temperature of your pipette (your pickling temperature is higher)

Dolf van den Berg
- Leusden, The Netherlands