Pre-reduction method for iron-bath melting reduction furnace

Abstract

The invention discloses a pre-reduction method for an iron-bath melting reduction furnace. Coal and iron ore are directly fed into a cyclone melting separator to form semi coke in the cyclone melting separator, then the semi coke is mixed with melted ore material to form a melted mixture composed of a pre-reduced ore material and the semi coke and finally the melted mixture is fed into a final reduction unit. The semi coke is prevented from being formed in a final reduction melting pool so that heat consumed during a forming process of the semi coke in the melting pool can be saved, the melting pool is easy to be kept at a high temperature, the semi coke is more sufficiently mixed with slag and reduction capacity of the melting pool is improved; meanwhile, the semi coke formed in the cyclone melting separator can be mixed well with the pre-reduced melted ore material before being fed into the melting pool, thereby a reduction effect of the semi coke on iron oxide in the pre-reduced melted ore material can be achieved just in the cyclone melting separator and a pre-reduction degree in the cyclone melting separator is improved.

Description

technical field [0001] The invention relates to an iron bath smelting reduction process, and more particularly, to a pre-reduction method for an iron bath smelting reduction furnace. Background technique [0002] The existing CCF (Cyclone Converter Furnace) iron bath smelting reduction method to produce molten iron is a smelting reduction method of iron bath type with great commercialization prospects. [0003] The method is a two-step method, which mainly includes two parts: "pre-reduction + pre-reduction ore powder melting" (at least partial melting) and final reduction of iron bath. The unit equipment of "pre-reduction + pre-reduction ore powder melting" is a smelting swirl flow Melting Cyclone or cyclone melting separator, the iron bath final reduction unit located under the "pre-reduction + pre-reduction and melting" unit is a metallurgical vessel with slag similar to the converter furnace type. The "pre-reduced ore powder melting" unit sits on the iron bath final redu...

AI Technical Summary

Problems solved by technology

[0007] The disadvantages of CCF coal addition technology are: 1) The pulverized coal or coal particles or the combination of the two directly added to the molten pool (hot metal or liquid slag) have to absorb more coal during the process of heating up and pyrolyzing to form semi-coke Heat, which will reduce the temperature of the iron bath in the final reduction unit, reduce the reduction speed in the reduction zone, and reduce the reduction speed and efficiency of the final reduction unit

At the same time, the content of ferrous oxide in the slag is also high, which is not good for the life of the iron bath molten pool.

2) In the CCF technology, the coal and mineral materials directly added to the molten pool have not been fully premixed. Therefore, the degree of mixing and contact between the semi-coke formed in the molten pool of the final reduction unit and the iron oxide in the slag is poor, reducing the semi-coke The reduction interface with iron oxide, and after entering the final reduction molten pool, the concentration of ferrous oxide drops rapidly, further reducing the reduction speed and efficiency of the final reduction unit