Process for producing cast iron

Claim 1

A PROCESS FOR TREATING CAST IRON TO PROMOTE THE FORMATION OF FREE GRAPHITE IN COMPACTED AND NODULAR FORM, WHICH PROCESS COMPRISES PROVIDING A BATH OF MOLTEN CAST IRON, ADDING TO SAID CAST IRON ABOUT 0.1% BY WEIGHT OF CAST IRON TO BE TREATED OF ONE OF THE DEOXIDIZERS IN THE GROUP CONSISTING OF CALCIUM-SILICON AND ALUMINUM, ENTRAINING POWDERED CALCIUM CARBIDE IN A STREAM OF INERT GAS, INJECTING SAID ENTRAINED CALCIUM CARBIDE INTO SAID MOLTEN CAST IRON THEREBY REDUCING THE SULFUR CONTENT OF SAID CAST IRON TO NOT MORE THAN 0.01%, INJECTING INTO THE DESULFURIZED CAST IRON SIMULTANEOUSLY AN INOCULANT AND NODULIZING AGENT, BOTH IN POWDERED FORM, SAID NODULIZING AGENT BEING ADDED IN AN AMOUNT SUFFICIENT TO IMPART TO SAID CAST IRON IN THE AS-CAST CONDITION A RETAINED AMOUNT OF NODULIZING AGENT EQUAL TO NOT MORE THAN 0.001%.