Process for refining pig iron

Claim 1

A PROCESS FOR REFINING MOLTEN FERROUS METAL BY SURFACE BLOWING WITH GASEOUS OXYGEN IN WHICH THE HEAT REQUIRED FOR THE REFINING IS PRODUCED BY REACTION OF THE OXYGEN WITH THE IMPURITIES IN THE MOLTEN METAL, WHICH COMPRISES INTRODUCING INTO A REACTION ZONE SOLID FERROUS METAL AND A PREDOMINANT PROPORTION OF MOLTEN CARBONCONTAINING FERROUS METAL, PROVIDING THE MOLTEN METAL WITH A SLAG COVER, INITIALLY DISPLACING THE SLAG COVER TO PROVIDE DIRECT CONTACT OF OXYGEN WITH SAID MOLTEN METAL, BLOWING A JET OF HIGH PURITY OXYGEN FROM A BLAST NOZZLE SUBSTANTIALLY VERTICALLY DOWNWARDLY ONTO THE SURFACE OF SAID MOLTEN METAL, SAID BLAST NOZZLE BEING SPACED BETWEEN ABOUT 150 MILLIMETERS AND ABOUT 2000 MILLIMETERS ABOVE THE SURFACE OF THE MOLTEN METAL, AND CONTROLLING THE IMPINGEMENT OF THE OXYGEN JET ON THE SURFACE OF SAID MOLTEN METAL SUCH THAT THE IMPACT PRESSURE OF THE BLAST JET ON A REFERENCE SURFACE SPACED FROM THE BLAST NOZZLE A DISTANCE EQUAL TO THE DISTANCE OF THE MOLTEN METAL SURFACE FROM THE BLAST NOZZLE IS MAINTAINED BELOW ABOUT 0.75 KG./SQ. C., AND ABOVE ABOUT 0.02 KG./SQ. CM., WHILE SUPPLYING THE OXYGEN AT A RATE SUFFICIENT TO COMPLETE THE REFINING IN ABOUT 12 TO ABOUT 30 MINUTES.