Air-base direct reduction iron-making method for reducing iron concentrate powder by self-reforming of gas rich in methane

Abstract

An air-base direct reduction iron-making method for reducing iron concentrate powder by self-reforming of gas rich in methane. The method provided by the invention belongs to the field of iron-making technology. The method is characterized in that through a technology combining a circulating fluidized bed and a two-section high temperature conveying bed, iron ore powder is dried and preheated andthen is fed into a circulating fluidized bed for pre-reduction; the pre-reduced iron ore powder is fed into a high temperature fast conveying bed for a deep and rapid reduction in the presence of reducing gas at a reaction temperature of 940 to 1000 DEG C and methane is cracked by a effect of direct reduction of iron simultaneously; in a cooling zone of the high temperature fast conveying bed, the reduced iron ore powder is mixed with reducing gas from a cooling circuit and is fast cooled to a temperature of 700 to 800 DEG C; and the reduced iron ore powder can be utilized for producing hot pressed blocks and cold pressed blocks produced through a cooling treatment of a third stage circulating fluidized bed. The air-base direct reduction iron-making method realizes self-reforming of gas rich in methane in a reducing furnace and has the advantages of high utilization rate, high efficiency, environmental protection, etc.

Description

technical field [0001] The invention belongs to the technical field of ironmaking, and in particular relates to a gas-based reduction ironmaking method for self-reforming of methane-rich coal gas to reduce iron fine powder. Background technique [0002] The blast furnace ironmaking process has become the most important ironmaking process at present due to its large-scale equipment, high production efficiency, long service life and the production of molten iron products suitable for steelmaking. With the rapid development of my country's iron and steel industry, large-scale blast furnaces, increasing demand for metallurgical raw materials, and increased environmental protection and energy-saving requirements, some shortcomings of the blast furnace ironmaking process have gradually emerged, such as excessive dependence on metallurgical coke, requirements The use of high-quality bulk iron-containing materials, high energy consumption, and serious pollution, etc., the traditional...

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Problems solved by technology

[0008] To sum up, the gas-based shaft furnace method has the advantages of mature technology and high efficiency, but it cannot directly use the concentrate powder; the gas-based fluidized bed method is limited by the source of hydrogen and the low reaction temperature, and the production cost is high and the efficiency is low

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