system based on ion exchange principle, will remove
both Hexavalent chromium as anion and Trivalent
chromium, Nickel, Iron etc. as cation, in a two
bed ion exchange system.
The static rinse after chrome palting drag out
tank, containing Hexavalent chrome ions and othe
cationic impurities like trivalent chrome, Nickel,
iron, copper etc. is pumped through chrome recovery
coloumns. The strongly acidic cation exchanger
removes trivalent chromium (and other cations)
while the macroracticular weak base anion exchange
resin removes the haxavalent chrome. This produces
deionised water which can be recycled in a closed
The hexavlent chromium is eluted from anion exchanger
with sodium Hydroxide in a concentrated solution.
This solution is further passed through a third
column containing strongly acidic resin in the
hydrogen form. to recover chromic acid which can
be recycled to the plating bath after concentrating
in an evaporator.