Method for making iron by smelting reduction

Abstract

The invention discloses a method for making iron by smelting reduction. The method comprises the following steps of firstly, preparing raw materials: secondly, drying pellets; thirdly, prereducing: continuously adding carbon-containing pellets into a coal shaft furnace, introducing fuel into a combustion chamber of the coal shaft furnace, performing mixed combustion on the fuel and combustion-supporting air, supplying heat to a reduction chamber through a refractory furnace wall between the combustion chamber and the reduction chamber, and stably controlling the furnace temperature in the reduction chamber to be 1,000 to 1,150DEG C; fourthly, finally reducing: adding high-temperature metallized pellets which are prereduced in the coal shaft furnace into a smelting gasifier through a spiral discharger and a discharging pipe; meanwhile, adding lump coal and lime into the furnace, blowing oxygen into the furnace, performing reducing and melting separation on raw materials under the atmosphere of high temperature and high reduction atmosphere, and regularly discharging generated molten iron and furnace clinker from an iron notch and a clinker notch. According to the method disclosed by the invention, heat is supplied to the smelting gasifier by coal oxygen combustion without coke, and high reaction intensity, high reaction speed and high volumetric utilization efficiency are realized.

Description

technical field [0001] The invention relates to an ironmaking method, in particular to a smelting reduction ironmaking method, which belongs to the field of non-blast furnace ironmaking. Background technique [0002] Since the 20th century, the production of blast furnaces has developed unprecedentedly, and the volume of blast furnaces has also continued to expand. Blast furnace ironmaking has been developed to this day, with reduced consumption, lower costs, and almost peak productivity, making great contributions to human civilization and economic development, and is still the main force in steel production. In the world's iron and steel industry, about 60% of steelmaking pig iron comes from blast furnaces, while in my country almost 100% comes from blast furnace ironmaking. However, in modern industrial production, blast furnace ironmaking production has encountered new challenges, and most of these challenges come from the development of the blast furnace itself, mainly...

AI Technical Summary

Problems solved by technology

From the raw material field in front of the iron to the sintering (or pelletizing) plant, coking plant, and then to the blast furnace ironmaking system, the production process is very long, and the total investment is very huge

[0004] (2) Blast furnace ironmaking must use coke, but the resource of coke coal is less and less, and it is not renewable

Higher and higher environmental protection requirements make the development of blast furnace ironmaking technology more and more difficult to meet the needs

[0005] (3) The traditional blast furnace relies too much on indirect reduction, and the indirect reduction degree is about 67%, that is, about 2 / 3 of the oxygen in the ore is removed by indirect reduction, so the reduction and smelting of iron oxides in the blast furnace generally takes a long time Time, that is, it takes 6.5~7 hours from the charging of the charge to the tapping of the blast furnace

[0007] The one-step smelting reduction furnace lining is severely eroded, and the energy of a large amount of hot gas is difficult to recycle, and the energy cost remains high

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