Method for producing steel

Claim 1

THE METHOD OF PRODUCING STEEL BY REFINING OF PIG IRON IN WHICH THE MAJOR PART OF THE DEPHOSPHORIZERS IN FINELY DIVIDED FORM ARE SUSPENDED IN A GAS AND INJECTED INTO THE BATH TO BE TREATED FROM ABOVE THE SURFACE OF SAID BATH BY MEANS OF A NOZZLE HAVING AN INNER CONDUIT AND AN OUTER CONDUIT CONCENTRIC TO THE INNER CONDUIT AND SURROUNDING IT, CHARACTERIZED BY THE FACT THAT DURING AT LEAST A PART OF THE PROCESS AN OXIDIZING GAS CONTAINING THE DEPHOSPHORIZER IN SUSPENSION IS INJECTED INTO THE BATH OF METAL THROUGH THE INNER CONDUIT OF THE NOZZLE AT A SPEED SUFFICIENTLY HIGH TO CAUSE IT TO PENETRATE THE SLAG ON THE SURFACE OF SAID BATH AND INTO SAID BATH, WHILE AN OXIDIZING GAS WHICH CONTAINS NO DEPHOSPHORIZER IS INJECTED ONTO SLAG FLOATING ON TOP OF THE METAL THROUGH THE OUTER CONDUIT OF THE NOZZLE AT A SPEED SUFFICIENTLY LOW TO AVOID ITS PENETRATION OF THE SLAG ON THE SURFACE OF SAID BATH, SAID LAST MENTIONED OXIDIZING GAS CONSISTING OF OXYGEN DURING THE FIRST PART OF THE OPERATION UNTIL THE SLAG HAS BECOME SUFFICIENTLY FOAMY, WHILE AT THE SAME TIME THERE IS INJECTED THROUGH THE INNER CONDUIT OF THE NOZZLE A MIXTURE OF OXYGEN AND POWDERED LIME, THE APPARENT DENSITY OF WHICH IS AT FIRST NO HIGHER THAN 3/10 KILOGRAMS PER CUBIC METER (S.T.P.), AND THEN GRADUALLY INCREASED AS THE FOAMING DEVELOPS, SAID INJECTION THROUGH THE OUTER CONDUIT OF THE NOZZLE BEING STOPPED AS SOON AS THE FOAMING HAS OCCURRED, AND THE OPERATION BEING CONTINUED, INJECTING SOLELY THROUGH THE INNER CONDUIT OF THE NOZZLE WITH AN INCREASINGLY LARGER PRESSURE.

Claim 2

THE METHOD OF PRODUCING STEEL BY REFINING OF PIG IRON IN WHICH THE MAJOR PART OF THE DEPHOSPHORIZERS IN FINELY DIVIDED FORM ARE SUSPENDED IN A GAS AND INJECTED INTO THE BATH TO BE TREATED FROM ABOVE THE SURFACE OF SAID BATH BY MEANS OF A NOZZLE HAVING AN INNER CONDUIT AND AN OUTER CONDUIT CONCENTRIC TO THE INNER CONDUIT AND SURROUNDING IT, CHARACTERIZED BY THE FACT THAT DURING AT LEAST A PART OF THE PROCESS AN OXIDIZING GAS CONTAINING THE DEPHOSPHORIZER IN SUSPENSION IS INJECTED INTO THE BATH OF METAL THROUGH THE INNER CONDUIT OF THE NOZZLE AT A SPEED SUFFICIENTLY HIGH TO CAUSE IT TO PENETRATE THE SLAG ON THE SURFACE OF SAID BATH AND INTO SAID BATH, WHILE AN OXIDIZING GAS WHICH CONTAINS NO DEPHOSPHORIZER IS INJECTED ONTO SLAG FLOATING ON TOP OF THE METAL THROUGH THE OUTER CONDUIT OF THE NOZZLE AT A SPEED SUFFICIENTLY LOW TO AVOID ITS PENETRATION OF THE SLAG ON THE SURFACE OF SAID BATH, SAID LAST MENTIONED OXIDIZING GAS CONSISTING OF OXYGEN DURING THE FIRST PART OF THE OPERATION UNTIL THE SLAG HAS BECOME SUFFICIENTLY FOAMY, WHILE AT THE SAME TIME THERE IS INJECTED THROUGH THE INNER CONDUIT OF THE NOZZLE A MIXTURE OF OXYGEN AND POWDERED LIME, THE APPARENT DENSITY OF WHICH IS AT FIRST NO HIGHER THAN 3/10 KILOGRAMS PER CUBIC METER (S.T.P.), AND THEN GRADUALLY INCREASED AS THE FOAMING DEVELOPS, SAID INJECTION THROUGH THE OUTER CONDUIT OF THE NOZZLE BEING STOPPED AS SOON AS THE FOAMING HAS OCCURRED, AND THE OPERATION BEING CONTINUED, INJECTING SOLELY THROUGH THE INNER CONDUIT OF THE NOZZLE WITH AN INCREASINGLY LARGER PRESSURE.