Desulfurization of molten ferrous metals

Claim 1

A METHOD FOR LOWERING THE SULFUR CONTENT OF MOLTEN IRON FROM THE RANGE OF ABOUT 0.025% TO 0.075% TO NOT MORE THAN 0.015% BY THE INJECTION OF CALCIUM CARBIDE INTO SAID MOLTEN IRON SAID METHOD NOT REQUIRING AGITATION BY GAS INJECTION SUBSEQUENT TO THE INJECTION OF CALCIUM CARBIDE AND REQUIRING NOT MORE THAN ABOUT 4 POUNDS OF CALCIUM CARBIDE PER TON OF IRON PER 0.01% OF SULFUR REMOVED IN SAID RANGE, SAID METHOD COMPRISING THE STEPS OF: I. PROVIDING IN A VESSEL MOLTEN IRON CONTAINING SULFUR IMPURITY IN AN AMOUNT OF AT LEAST 0.025%. II. PROVIDING FINELY DIVIDE PARTICLES OF CALCIUM CARBIDE IN A GAS STREAM SUBSTANTIALLY ALL OF SAID FINELY DIVIDED PARTICLES OF CALCIUM CARBIDE BEING NOT LARGER THAN 200 MICRONS, AT LEAST ABOUT 50 PERCENT OF SAID PARTICLES BEING NOT LARGER THAN 50 MICRONS AND AT LEAST 20 PERCENT BEING NOT LARGER THAN 10 MICRONS AND THE AGGREGATE OF SAID PARTICLES OF CALCIUM CARBIDE HAVING A FISCHER SUB-SIEVE NUMBER OF LESS THAN ABOUT 12. III. INJECTING SAID CALCIUM CARBIDE CONTAINING GAS STREAM AT A VELOCITY OF NOT MORE THAN ABOUT 15 FEET PER SECOND INTO THE LOWER 75% OF THE TOTAL DEPTH OF MOLTEN IRON TO THEREBY REDUCE THE SULFUR CONTENT OF SAID MOLTEN IRON AND PROVIDE IN SAID MOLTEN IRON A SULFUR CONTENT OF NOT MORE THAN 0.015% UPON TERMINATION OF CALCIUM CARBIDE INJECTION.

Claim 2

A METHOD FOR LOWERING THE SULFUR CONTENT OF MOLTEN IRON FROM THE RANGE OF ABOUT 0.025% TO 0.075% TO NOT MORE THAN 0.015% BY THE INJECTION OF CALCIUM CARBIDE INTO SAID MOLTEN IRON SAID METHOD NOT REQUIRING AGITATION BY GAS INJECTION SUBSEQUENT TO THE INJECTION OF CALCIUM CARBIDE AND REQUIRING NOT MORE THAN ABOUT 4 POUNDS OF CALCIUM CARBIDE PER TON OF IRON PER 0.01% OF SULFUR REMOVED IN SAID RANGE, SAID METHOD COMPRISING THE STEPS OF: I. PROVIDING IN A VESSEL MOLTEN IRON CONTAINING SULFUR IMPURITY IN AN AMOUNT OF AT LEAST 0.025%. II. PROVIDING FINELY DIVIDE PARTICLES OF CALCIUM CARBIDE IN A GAS STREAM SUBSTANTIALLY ALL OF SAID FINELY DIVIDED PARTICLES OF CALCIUM CARBIDE BEING NOT LARGER THAN 200 MICRONS, AT LEAST ABOUT 50 PERCENT OF SAID PARTICLES BEING NOT LARGER THAN 50 MICRONS AND AT LEAST 20 PERCENT BEING NOT LARGER THAN 10 MICRONS AND THE AGGREGATE OF SAID PARTICLES OF CALCIUM CARBIDE HAVING A FISCHER SUB-SIEVE NUMBER OF LESS THAN ABOUT 12. III. INJECTING SAID CALCIUM CARBIDE CONTAINING GAS STREAM AT A VELOCITY OF NOT MORE THAN ABOUT 15 FEET PER SECOND INTO THE LOWER 75% OF THE TOTAL DEPTH OF MOLTEN IRON TO THEREBY REDUCE THE SULFUR CONTENT OF SAID MOLTEN IRON AND PROVIDE IN SAID MOLTEN IRON A SULFUR CONTENT OF NOT MORE THAN 0.015% UPON TERMINATION OF CALCIUM CARBIDE INJECTION.