Method of preparing preliminary metal or steel pig iron containing phosphorus

Claim 1

IN THE METHOD FOR PRODUCING PRELIMINARY METAL AND STEEL FROM A PIG IRON MELT HAVING AN ARBITRARY PHOSPHORUS CONTENT BY REFINING SAID MELT WITH OXYGEN-CONTAINING AGENTS WITH THE SIMULTANEOUS ADDITION OF SLAG-FORMING SUBSTANCES IN A REFINING VESSEL, IN WHICH A REFINING GAS IS BLOWN ONTO THE LAYER OF THE SLAG IN SUCH A MANNER THAT, DURING AN INITIAL STAGE OF THE REFINING PROCESS, SAID GAS WILL NOT PENETRATE THE SLAG LAYER AND REACH THE SURFACE OF SAID MELT AND CONTACT THE LATTER, THEREBY CONTINUOUSLY OXIDIZING THE FEO CONTAINED IN THE SLAG TO FE2O3, THE FE8O3 CAUSING DEPHOSPHORIZATION AT THE INTERFACE BE TWEEN THE SLAG AND THE MELT AND THE FEO THEREBY FORMED BEING REOXIDIZED TO FE2O3 BY THE OXYGEN OF THE REFINING GAS, THE IMPROVEMENT WHICH COMPRISES STOPPING THE SAID BLOWING WITH REFINING GAS AT A STAGE WHEREIN DEPHOSPHORIZATION OF THE MELT IS COMPLETED AND SAID MELT HAS A CARBON CONTENT HIGHER THAN THAT FINALLY REQUIRED AND WHEREIN SAID CARBON CONTENT CAN BE ADJUSTED TO THE FINAL COARBON CONTENT REQUIRED BY A SUBSEQUENT HEAT TREATING STEP, MAINTAINING THE TEMPERATURE OF SAID MELT TO PERMIT FURTHER BOILING THEREOF, AND ADJUSTING THE CARBON CONTENT OF SAID MELT TO THE CONTENT FINALLY REQUIRED DURING SAID FURTHER BOILING.