Method for top blowing pulverulent burnt lime and oxygen into cast iron for refining same

Claim 1

IN A METHOD FOR MAKING LOW PHOSPHORUS, LOW NITROGEN STEEL FROM PIG IRONS OF WIDELY VARYING PHOSPHORUS CONTENT, THE STEP OF BLOWING THROUGH A LANCE HAVING AN OUTLET OPENING OF PREDETERMINED CROSS-SECTIONAL AREA, A JET STREAM OF SUBSTANTIALLY PURE OXYGEN HAVING SUSPENDED THEREIN PULVERULENT BURNT LIME AGAINST THE TOP SURFACE OF A MOLTEN BATH OF SAID PIG IRON IN DOWNWARD DIRECTION WITH SUCH A FORCE AND IN SUCH A MANNER THAT SAID JET STREAM OF OXYGEN WITH SAID PULVERULENT LIME SUSPENDED THEREIN PENETRATES DOWNWARDLY THROUGHOUT THE DEPTH OF THE BATH INTO A REGION NEAR THE BOTTOM THEREOF WITH THE CROSS-SECTIONAL AREA OF SAID PENETRATING JET STREAM REMAINING SUBSTANTIALLY EQUAL TO THE CROSS-SECTIONAL AREA OF THE OUTLET OPENING OF THE LANCE, WHEREBY, DUE TO THE SUBSTANTIALLY COMPLETE PENETRATION OF THE BATH DEPTH BY THE OXYGEN HAVING A PULVERULENT LIME SUSPENDED THEREIN, THE REACTION THEREOF WITH THE PIG IRON BATH WILL OCCUR IN THAT REGION OF SAID BATH WHERE IT IS MOST EFFICIENT WHILE, SIMULTANEOUSLY, DUE TO THE SUBSTANTIALLY CONSTANT DIAMETER OF THE JET DURING PENETRATION OF THE BATH, THERE WILL BE AVOIDED WITHIN THE BATH ANY SUBSTANTIAL TURBULENCE THEREOF WHICH MIGHT ADVERSELY AFFECT THE REACTION BETWEEN THE PIG IRON AND THE OXYGEN HAVING PULVERULENT LIME SUSPENDED THEREIN.