Method of producing nodular iron

Claim 1

IN THE PRODUCTION OF AS-CAST NODULAR IRON FROM A MOLTEN GRAY IRON MIX BY THE USE OF RARE EARTH METALS AS THE NODULARIZING AGENT ADDED TO SAID MOLTEN MIX, THE METHOD OF INCREASING THE EFFICIENCY OF INCORPORATION OF SAID AGENT INTO SAID MIX AND OF DECREASING THE AMOUNT OF SAID AGENT ADDED TO SAID MIX AND THE AMOUNT OF SAID AGENT LOST DURING SAID ADDITION WHICH COMPRISES THE STEPS OF PREPARING A MOLTEN GRAY IRON MIX, TREATING SAID MIX WITH A SLAG MATERIAL COMPRISING CALCIUM CARBONATE AND A CARBONACEOUS MATERIAL AND CALCIUM FLUORIDE FOR ENHANCING THE RESPONSIVENESS OF SAID MIX TO THE EFFECT OF SAID NODULARIZING AGENT, THEREAFTER ADDING TO SAID MIX BEFORE CASTING A RARE EARTH METAL FLUORIDE AND A REDUCING AGENT THEREFOR, EFFECTING REDUCTION OF SAID RARE EARTH METAL FLUORIDE TO SAID RARE EARTH METAL BY SAID REDUCING AGENT IN SAID MOLTEN MIX FOR NODULARIZING ACTION THEREIN, AND POURING THE THUS TREATED MIX INTO A MOLD TO FORM SAID CASTING.