A method for producing metallized pellets by direct reduction of sensible heat of high-temperature oxidation pellets

Abstract

The invention belongs to the technical field of metallurgy, and in particular relates to a method for producing metallized pellets by direct reduction of sensible heat of high-temperature oxidized pellets. The present invention adopts a single chain grate-rotary kiln method to prepare high-temperature oxidized pellets, uses its sensible heat to directly carry out a reduction reaction with a reducing agent (coal), and then uses normal-temperature reduced coal for heat exchange and cooling, and after magnetic separation and separation, obtains Metallized pellet products and dried reducing agents (including retort coal char). The invention can recycle carbonized coal coke and reuse high-purity coal gas. The recovered carbonized coal coke can be used as a reducing agent again, and high-purity coal gas can be used for oxidation pellet rotary kiln and flame-trap type deep reduction rotary kiln. Energy, no additional heating energy is needed. The patent can reduce coal consumption by 40% to 60%, and the high-purity gas burned can reduce carbon emissions, which is energy-saving and environment-friendly.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for producing metallized pellets through direct reduction using sensible heat of high-temperature oxidation pellets. Background technique [0002] my country is a big country of iron and steel. In 2014, the steel output exceeded 1.126 billion tons (of which crude steel was 820 million tons), and the annual output of grate-rotary kiln method and sintering machine method oxidized pellets reached more than 2 billion tons; the amount of scrap steel ( Including DRI) there is a gap of 29 million tons per year, while the production of non-coking iron (direct reduced iron) products accounts for less than 1.0% of the world's production, with an annual production scale of less than 600,000 tons. As my country's coking coal reserves become increasingly poor and environmental protection problems become more and more serious, the state has introduced more relevant indus...

AI Technical Summary

Problems solved by technology

[0005] Among them, the traditional coal-based tunnel kiln method to produce direct reduced iron (sponge iron) must use expensive refractory tanks (consumption of refractory tanks per ton of reduced iron is generally 230 to 280 yuan / ton), and the annual production capacity of a single production line is at most not To 30,000 tons, backward process equipment, low production capacity, large area, high energy consumption, long reduction time, high production and operation costs, high labor intensity, poor product quality, etc., resulting in high production and operation costs and poor sales. question

[0006] Although the coal-based tankless tunnel kiln method can abandon the expensive silicon carbide tank of the tunnel kiln method, greatly shorten the reduction time, reduce energy consumption and production costs, it can also combine various high-grade ores, various low-poor and refractory iron ores, and composite For ore and iron-containing waste, TFe≥90% metallic iron or even granular iron products can be obtained after reduction, which enables the sustainable development of refractory ore resources, but the production line still occupies a large area, the production line operation is still cumbersome, and the reduction time is still It takes 7h to 9h, the investment scale is also large, and the reduction process is complicated. Therefore, this tankless reduction kiln needs to be further improved and optimized

[0007] The coal-based one-step rotary kiln process technology is gradually mature and the operating cost is low, and it is gradually being promoted. However, it has strict requirements for reducing coal. Granular high-quality long-flame coal and lignite must be used as reducing agents. The operation is difficult and the investment scale is relatively small. Larger, the annual production capacity of a single production line is less than 200,000 tons; the coal-based two-step rotary kiln process technology is gradually mature, but there is a shortage of rich massive iron ore. High-grade oxidized pellets are used, and the production and operation costs are high. Suitable for our national conditions

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