Etching process

Claim 1

THE CONTINUOUS PROCESS OF ETCHING METAL WITH FERIC CHLORIDE WHICH COMPRISES THE STEPS OF BRINGING METAL TO BE ETCHED INTO CONTACT WITH A LIQUID ETCHING BATH THE ACTIVE INGREDIENT OF WHICH IS FERRIC CHLORIDE, TO FORM IN SAID BATH A LIQUID MIXTURE OF FERRIC CHLORIDE, FERROUS CHLORIDE, AND CHLORIDE OF THE ETHED METAL, CONTINUING THE ETCHING UNTIL THE CONCENTRATION OF ETCHED METAL CHLORIDE IN SAID BATH APPROACHES THE SATURATION POINT AT THE WORKING TEMPERATURE OF THE BATH, CONTINUOUSLY WITHDRAWING FROM THE BATH A QUANTITY OF SAID LIQUID CONTAINING SAID CONCENTRATION OF ETCHED METAL CHLORIDE, SUBJECTING THE WITHDRAWN LIQUID TO REACTION WITH CHLORINE GAS TO CONVERT AT LEAST A SUBSTANTIAL PART OF THE FERROUS CHLORIDE THEREIN TO FERRIC CHLORIDE, COOLING THE WITHDRAWN LIQUID TO CRYSTALLIZE OUT A SUBSTANTIAL PART OF THE ETCHED METAL CHLORIDE, REMOVING THE ETCHED METAL CHLORIDE CRYSTALS FROM THE COOLED LIQUID, REHEATING THE COOLED LIQUID TO THE WORKING TEMPERATURE OF THE ETCHING BATH, AND RETURNING THE REGENERATED LIQUID TO THE ETCHING BATH.