ReFe - Iron (Fe) removal from rinse water in pickling lines
It is generally accepted that the presence of Fe has a negative influence on both zinc consumption and the quality of the galvanized steel and therefore should be avoided. WTN Water Treatment developed the ReFe-system to overcome this problem.
WTN Water Treatment has developed a continuous Fe removal process for flux/rinse bath solutions, which completely eliminates the production of waste. The Fe is recovered as an Fe-containing HCl solution which can be used to modify the composition of pickling baths.
Process description
The unit consists of three different sections:
neutralisation section
ion-exchange section
stripping section
All ion-exchange processes are highly sensitive to solid particles, which inter- fere with the process as a whole. After filtration with a standard plate-filter the feed solution with controlled pH is pumped through the ion-exchange col- umn where the Fe is absorbed by the resin.
After leaving the column, the liquid is returned to the rinse/flux bath. When the resin is saturated with Fe, it must be stripped and regenerated.
The stripping/regeneration solution is pumped from a storage vessel through the column into another vessel. An ex- change of Fe and HCl takes place in the column. Fe is dissolved in the HCl, while the HCl is absorbed by the resin. It is not necessary to rinse the column as pollution is no problem here.
Additionally
Next to Fe removal savings can be made by control of composition and performance of the flux.
To make it easy for you WTN offers its customers additionally:
Laboratory support and advice
GALVA FLUX - Fluxing salt
Trade in zinc ashes and dross
Results obtained in a Dutch plant:
Decrease in zinc-pickup > 25%
Efficiency of Ni from 25 to >80%
Increase production rate >10%
Decrease in zinc ash production
Decrease in dross production
Dross removal before treatment:
8t/2 wk; at present: 2t/6 wk
