Production technology and device of externally heated shaft furnace coal-based direct reduced iron

Abstract

The invention discloses a production process of externally-heated type vertical furnace coal based direct reduced iron. The production process comprises the following steps of: adopting powdered iron and pulverized coal as the materials for uniformly mixing to obtain a mixture with a C / O ratio of 0.95-1.1; preparing the mixture into spheres with particle diameter of 6mm-20mm, and drying until the moisture content is not more than 2wt%; feeding the mixture to a reduction furnace for carrying out a reduction reaction. The invention further discloses a corresponding production device. According to the production process and the production device of the externally-heated type vertical furnace coal based direct reduced iron disclosed by the invention, the carbon-containing pellets can be manufactured; and the reduced products are ball-milled and selected, so that the use of the powdered iron of various grades is adapted on the condition of ensuring the grades of the product; the externally-heated type vertical furnace capable of expanding capacity in a modularized manner is adopted, so that the metallization ratio of the product can be ensured, the yield can be adjusted and the production cost can be lowered.

Description

technical field [0001] The invention relates to the technical field of metallurgy, in particular to a production process and a production device of an externally heated shaft furnace coal-based direct reduced iron. Background technique [0002] In terms of production technology of coal-based direct reduction iron with external heating shaft furnace, the key technology is not only the structure of shaft furnace body, but also the form of external heating shaft furnace, the processing technology of raw materials used and the post-processing technology of shaft furnace products. The earliest externally heated shaft furnace coal-based direct reduction iron production process technology appeared in 1971, namely the KINGLORMETOR process, referred to as the KM process, and some domestic researchers were influenced by this technology and published on the key device - externally heated shaft furnace Corresponding research results, such as publication number CN101832706A "external com...

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Problems solved by technology

[0006] The above-mentioned disclosed technology has the same feature that the reduction reaction chamber is similar to a tube and stands upright in the furnace. In order to overcome the problem of thermal expansion of materials and liquid phase at high temperature, the KM process uses a mixture of iron ore and reduced coal to enter the furnace, and the reduction temperature is controlled at Around 1050°C, other methods are difficult to increase the reduction temperature without other technical support, and the reduction time is longer

Since the reduction product only adopts simple crushing and magnetic separation, in order to ensure the full iron grade of the product, the requirements for the iron content grade of the raw material are relatively high, and the ordinary iron concentrate powder with about 63% iron content is used, and the product quality is low, and it is difficult to achieve the full iron grade. Content greater than 90%

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