Rational technological solutions in production of pig iron in blast furnaces of Magnitogorsk Iron and Steel Works

Abstract

The main factors affecting the specific consumption of natural gas have been identified. The most significant of them for the existing conditions are the process oxygen consumption, the reactivity of coke (CRI - coke reactivity index) and the hot strength of the coke (CSR - coke strength after reaction). The increase in the specific consumption of natural gas in the shop on average from 106.7 to 135.2 m3/t of pig iron with a replacement equivalent of at least 0.7 kg/m3 was facilitated by an increase in the oxygen content from 26.95 to 27.4 % and an increase in the reactivity of coke from 33.4 to 35.1 %. The technology of loading high-quality sinter from factory No. 5 into blast furnaces of Magnitogorsk Metallurgical Plant (MMK) has been mastered. An increase in the factory’s agglomerate content in the iron ore part of the charge by every 10 % increased the blast furnace productivity by 21.1 t/day while reducing the specific consumption of coke by 2.8 kg/t of pig iron. A local mode for loading flushing materials, depending on the hot strength of coke according to CSR has been developed and implemented.1. Into the ore ridge zone when coke is supplied with the CSR of more than 40%.2. Into different zones with the CSR less than 40 %:– to the axial zone, if the CSR is less than 90 % of the average value for the previous 5 days;– to the ore ridge zone, if the CSR is more than 110 % of the average value for the previous 5 days;– evenly over the top section, if the CSR is 90–110 % of the average value for the previous 5 days.