Ferric chloride is corrosive to concrete. Any spills should be readily neutralized, absorbed, and removed. Do not try to wash down the spill because that will only dilute it and then spread it.
A two component epoxy flooring overlayment and coating system has worked pretty well for our...
As a manufacturer of ferric chloride who frequently trials the material at WTPs and WWTPs, we recommend that no metal (except for titanium and possibly Hastelloy-C) be used for any wetted parts, regardless of the concentration of the ferric chloride. The 5% FeCl3 will eat through the metal far...