Method for directly reducing and producing metallized pellets by utilizing sensible heat of high-temperature oxidized pellets

Abstract

The invention belongs to the technical field of metallurgy, in particular to a method for directly reducing and producing metallized pellets by utilizing sensible heat of high-temperature oxidized pellets. The method comprises the following steps: preparing high-temperature oxidized pellets by adopting a single-chain grate-rotary kiln process, and utilizing the sensible heat of the high-temperature oxidized pellets to directly carry out reduction reaction with a reducing agent (coals); then, adopting normal-temperature reducing coal to carry out heat exchange and cool, and obtaining metallized pellet products and a dried reducing agent (including destructive distillation cokes) after magnetic separating. The method can be used for recycling the destructive distillation cokes and recycling high-purity coal gas; the recycled destructive distillation cokes can be used as a reducing agent; the high-purity coal gas can provide energy resources for an oxidized pellet rotary kiln and a muffle type deep-reduction rotary kiln without additionally introducing energy resources for heating. The method can reduce coal consumption by 40%-60%; and the burnt high-purity coal gas can be used for reducing carbon emission, saving energy and protecting environment.

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...

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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 susta

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