Pneumatic process for the refining of basic pig iron

Claim 1

THE PNEUMATIC METHOD OF REFINING AMERICAN BASIC PIG IRON TO LOW CARBON, STEEL CONTAINING NOT MORE THAN 0.045 PHOSPHORUS AND NOT MORE THAN 0.005 NITROGEN, COMPRISING CHARGING A QUANTITY OF MOLTEN AMERICAN BASIC PIG IRON AT A TEMPERATURE OF BETWEEN 2400-2700* F. ONTO A BASIC HEARTH, ADDING MATERIALS FOR FORMING A BASIC SLAG, APPLYING A BLAST OF AIR TO THE SURFACE ONLY OF SAID MOLTEN BATH AT A RATE OF ABOUT 1500 CUBIC FEET PER MINUTE PER TON OF MOLTEN METAL CHARGED, SAID BLAST BEING APPLIED AT AN ANGLE OF INCIDENCE WITH SAID SURFACE OF BETWEEN 9 AND 18* AND AT A BLAST VELOCITY OF BETWEEN 300 AND 500 FEET PER SECOND TO MAINTAIN SAID SLAG IN A STATE OF ROLLING AGITATION WITHOUT BORING OF THE BLAST INTO SAID MOLTEN METAL, ADDING COLD MATERIAL FROM THE GROUP CONSISTING OF FERROUS SCRAP AND IRON OXIDE WHEN THE TEMPERATURE OF SAID MOLTEN IRON APPROACHES ABOUT 3000* F. TO MAINTAIN THE TEMPERATURE BELOW 3100* F., AND DISCONTINUING SAID BLAST AT THE CARBON END POINT.