Reducing furnace, and technology for directly reducing coal-containing pellets through preheating outside coal base

Abstract

The invention provides a reducing furnace. The reducing furnace comprises a furnace wall, at least one reducing tank and at least one combustion tank, and the at least one reducing tank and the at least one combustion tank are alternately arranged. The top of each reducing tank is connected with a raw material feeding device, and the bottom of each reducing tank is provided with a material outlet. The top of each combustion tank is connected with a fuel feeding device, and the bottom of each combustion tank is provided with an ash outlet. The invention also provides a technology for directly heating coal-containing pellets through preheating outside a coal base. The technology comprises the following steps: 1, mixing and pelletizing an iron-containing raw material, coal dust and a binder to obtain coal pellets; and 2, providing the reducing furnace, adding the pellets to the reducing tank(s) through the raw material feeding device(s), adding fire coal to the combustion tank(s) through the fuel feeding device(s), allowing the pellets and the fire coal to independently move from top to bottom, heating and reducing the pellets to form spongy iron, and discharging the spongy iron. The reducing furnace and the reducing technology have the advantages of high shaft furnace productivity, adoption of non-coking coal as a reducing agent in coal base reduction, adoption of cheap coal as a heat source, and production of the direct reduction iron for steel making.

Description

technical field [0001] The invention belongs to the ironmaking field of the metallurgical industry, is a non-blast furnace ironmaking method, and particularly relates to a reduction furnace and a coal-based external preheating coal-containing pellet direct reduction process. Background technique [0002] Direct reduced iron (DRI), also known as sponge iron, is formed by reducing iron ore, iron concentrate or iron-containing raw materials with natural gas or non-coking coal as a reducing agent. Depending on the reducing agent, the chemical composition of the produced DRI is also different. As smelting steel types have stricter requirements on residual elements, especially steel products such as nuclear power, hydrogenation, and power stations, the use of ordinary returned scrap steel and purchased scrap steel for smelting can no longer meet the product’s requirements for residual elements. Due to its very low content of impurity elements, direct reduced iron is often used to...

AI Technical Summary

Problems solved by technology

The rotary hearth furnace has achieved industrial production in the treatment of dust containing Fe, Zn, Cr, and Ni in iron and steel plants. The disadvantage is that the sponge iron (DRI) has high gangue and sulfur content, which leads to an increase in the amount of steelmaking slag in the electric furnace and electrode consumption. Difficult to be directly used in the production of direct reduced iron for steelmaking

Due to the strict requirements on raw materials and fuels, the high investment and operating costs per unit capacity, the difficulty in stable operation, and the small production scale (maximum 150,000 t / year), it is difficult to become the main process for the development of direct reduced iron in my country

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