Method of operating an iron-refining basic converter and for refining iron into steel

Claim 1

A METHOD OF OPERATING A BOTTOM-BLOW IRON-REFINING BASIC CONVERTER, COMPRISING THE STEPS OF: (A) PASSING A GAS STREAM CONTAINING BETWEEN SUBSTANTIALLY 25% AND 45% BY VOLUME OXYGEN THROUGH A FIRST MELT OF RELATIVELY LOW-PHOSPHORUS PIG IRON IN SAID CONVERTER IN THE PRESENCE OF A SLAG FORMER TO PRODUCE A SLAG AND LIQUID STEEL; (B) DRAINING SAID LIQUID STEEL FROM SAID CONVERTER WHILE LEAVING AT LEAST PART OF SLAG THEREIN; (C) ADDING A RELATIVELY HIGH-PHOSPHORUS BASIC PIG IRON CONSISTING ESSENTIALLY OF 3.5 TO 4 WEIGHT PERCENT CARBON, 0.3 TO 0.6 WEIGHT PERCENT SILICON, 0.8 TO 1.3 WEIGHT PERCENT MANGANESE, 1.5 TO 2 WEIGHT PERCENT PHOSPHORUS AND 0.4 TO 0.8 WEIGHT PERCENT SULPHUR THE BALANCE BEING SUBSTANTIALLY ENTIRELY IRON, TO SAID CONVERTER; (D) PASSING AN OXYGEN-CONTAINING GAS STREAM THROUGH SAID HIGH-PHOSPHORUS BASIC PIG IRON TO EFFECT A REACTION OF SAID SLAG THEREWITH, THEREBY REFINING SAID HIGH-PHOSPHORUS BASIC PIG IRON; (E) ADDING A FRESH MELT OF SAID LOW-PHOSPHORUS PIG IRON TO SAID CONVERTER; AND (F) REPEATING STEPS (A) THROUGH (E) TO ALTERNATELY REFINE SAID LOW-PHORPHORUS AND SAID HIGH-PHOSPHORUS PIG IRONS.

Claim 2

A METHOD OF OPERATING A BOTTOM-BLOW IRON-REFINING BASIC CONVERTER, COMPRISING THE STEPS OF: (A) PASSING A GAS STREAM CONTAINING BETWEEN SUBSTANTIALLY 25% AND 45% BY VOLUME OXYGEN THROUGH A FIRST MELT OF RELATIVELY LOW-PHOSPHORUS PIG IRON IN SAID CONVERTER IN THE PRESENCE OF A SLAG FORMER TO PRODUCE A SLAG AND LIQUID STEEL; (B) DRAINING SAID LIQUID STEEL FROM SAID CONVERTER WHILE LEAVING AT LEAST PART OF SLAG THEREIN; (C) ADDING A RELATIVELY HIGH-PHOSPHORUS BASIC PIG IRON CONSISTING ESSENTIALLY OF 3.5 TO 4 WEIGHT PERCENT CARBON, 0.3 TO 0.6 WEIGHT PERCENT SILICON, 0.8 TO 1.3 WEIGHT PERCENT MANGANESE, 1.5 TO 2 WEIGHT PERCENT PHOSPHORUS AND 0.4 TO 0.8 WEIGHT PERCENT SULPHUR THE BALANCE BEING SUBSTANTIALLY ENTIRELY IRON, TO SAID CONVERTER; (D) PASSING AN OXYGEN-CONTAINING GAS STREAM THROUGH SAID HIGH-PHOSPHORUS BASIC PIG IRON TO EFFECT A REACTION OF SAID SLAG THEREWITH, THEREBY REFINING SAID HIGH-PHOSPHORUS BASIC PIG IRON; (E) ADDING A FRESH MELT OF SAID LOW-PHOSPHORUS PIG IRON TO SAID CONVERTER; AND (F) REPEATING STEPS (A) THROUGH (E) TO ALTERNATELY REFINE SAID LOW-PHORPHORUS AND SAID HIGH-PHOSPHORUS PIG IRONS.