Iron-containing material pretreatment and composite injection method and system

Abstract

The invention provides an iron-containing material pretreatment and composite injection method and system. The method comprises the following steps of (1) crushing and grinding an iron-containing material, and then carrying out dehydration drying treatment and primary preheating pre-reduction treatment on the iron-containing material; (2) carrying out secondary preheating and pre-reduction treatment on the iron-containing material subjected to the primary preheating and pre-reduction treatment; (3) premixing pulverized coal, a flux and the iron-containing material subjected to secondary preheating and pre-reduction treatment in an injection pipeline before being injected into a smelting reduction furnace, so that sensible heat carried by the iron-containing material preheats the pulverized coal and the flux; and (4) blowing the premixed mixed material into the smelting reduction furnace. According to the method, the iron-containing material treatment efficiency is high, the process is short, the comprehensive utilization rate of energy is high, the coal consumption of an iron bath smelting reduction process can be reduced to 850 kg / t or below, and the heat efficiency is increased by 3-5%.

Description

technical field [0001] The invention relates to the technical field of raw fuel pretreatment in a smelting reduction process, in particular to a method and system for pretreatment of iron-containing materials and composite injection. Background technique [0002] The iron bath smelting reduction process is a smelting reduction metallurgical process using non-coking coal powder and iron ore powder to reduce iron oxides to metallic iron with carbon in a high-temperature molten state. It has strong raw material adaptability, short process flow, With the advantages of less environmental pollution and good quality of molten iron, it is an advanced ironmaking technology to solve the problems of my country's lack of coking coal resources and environmental protection. [0003] The smelting reduction production process is currently dominated by the "two-step method", that is, the "pre-reduction" + "final reduction" process. The fluidized bed technology used in the iron bath smelting ...

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Problems solved by technology

The fluidized bed technology used in the iron bath smelting reduction process uses the high-temperature gas generated by the smelting reduction furnace to preheat the ore powder, but the traditional fluidized bed process directly uses the gas generated by the smelting reduction furnace, which has a high degree of oxidation and high quality. Poor, poor reducing ability, and only pre-reduced by the first-stage circulating fluidized bed, resulting in poor pre-reduction effect of iron-containing materials, and the pre-reduction degree is lower than 20%.

[0004] At the same time, in the traditional iron bath smelting reduction process, coal powder and mineral powder are transported by two different delivery pipelines, which are connected to different solid spray guns and injected into the smelting reduction furnace. After entering the smelting reduction furnace, the mixing effect of coal powder and mineral powder Poor, the furnace temperature of pulverized coal is low, and the surface activity is low, which seriously affects the heat transfer and mass transfer reaction rate of the smelting reduction reaction

Pulverized coal needs to absorb a large amount of heat to reach the reaction temperature before the smelting reduction reaction can proceed. The reaction time is prolonged and the reaction is not sufficient. Part of the material particles will be carried out of the furnace with the rising gas, resulting in waste of materials.

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