Method and system for smelting reduction ironmaking with thick slag layer

Abstract

The invention belongs to the ironmaking field, and especially relates to a thick slag layer smelting reduction ironmaking method and a system thereof. The method comprises the following steps: a mixture of ore powder and a flux as well as combustion-supporting gas are in fluid connection with an upper spray gun (2) at middle part, and a fuel and combustion-supporting gas are in fluid connection with a lower spray gun (3) at lower part for injecting into a smelting reducing furnace; then injected in the smelting reducing furnace, steps of powder ore smelting, reduction and slagging can be completed in the smelting reducing furnace by one step, molten iron and slag are generated, then discharged from an iron / slag outlet (4) at lower part of the furnace; high temperature flue gas generated during an ironmaking process is introduced into a waste heat power generation boiler (7) through a flue (6) at top, is introduced into a heat exchange fluidized bed (10) by a first gravity deduster (8); and passes through a second gravity deduster (11), a cloth bag deduster (12), an induced draught fan (13) and a chimney (14) and then is discharged into atmosphere. The method has the advantage of high energy utilization efficiency, short production flow, high smelting efficiency, low energy consumption and low production cost.

Description

technical field [0001] The invention belongs to the field of non-blast furnace ironmaking in the metallurgical industry, and in particular relates to a method and system for smelting reduction of a thick slag layer. Background technique [0002] The traditional ironmaking technology is a long-process process based on blast furnace ironmaking. In the process of blast furnace ironmaking, lump ore and coke need to be applied. Therefore, it has the disadvantages of long blast furnace ironmaking process, high energy consumption, and large investment. Therefore, the technology of using fine ore to directly smelt iron has been proposed. [0003] At present, the non-blast furnace ironmaking technologies that have been industrialized include COREX and FINEX. However, these two processes are two-stage ironmaking processes. Carrying out smelting reduction, the reduction and melting of molten iron cannot be realized in one step, and these two processes also require a certain amount of ...

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Problems solved by technology

[0002] The traditional ironmaking technology is a long-process process based on blast furnace ironmaking. In the process of blast furnace ironmaking, lump ore and coke need to be applied. Therefore, it has the disadvantages of long blast furnace ironmaking process, high energy consumption, and large investment. Therefore, the technology of using fine ore to directly smelt iron has been proposed.

[0003] At present, the non-blast furnace ironmaking technologies that have been industrialized include COREX and FINEX. However, these two processes are two-stage ironmaking processes. Carrying out smelting reduction, the reduction and melting of molten iron cannot be realized in one step, and these two processes also require a certain amount of coke or coke in the production process, and the coke-free ironmaking has not been fully realized. Due to the complexity of process control, productivity and energy Therefore, there is a phenomenon that non-blast furnace ironmaking process cannot replace blast furnace ironmaking process; and there are also ironmaking processes using fine ore one-step smelting, such as DIOS in Japan and AISI in the United States. The HIsmelt process in Australia and the Romelt process in Russia, etc., although these processes are all for the reduction and melting of fine ore in a furnace, some ore powder falls from the top, and some are sprayed into the slag. At the same time, all combustion-supporting The gas is blown at the top, but these processes have problems such as serious refractory burning, high energy consumption, and unsmooth process during the test process. Therefore, industrialization has not yet been realized.

[0004] In short, there are still some unresolved problems in the current one-step direct smelting process of fine ore, such as the addition method of the charge affects the melting and reduction speed of the charge; The heat utilization efficiency of the gas is not high, and there will be incomplete combustion; the utilization efficiency of the flue gas at the top of the furnace is not high, etc.

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