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Iron-making method adopting carbothermal pre-reduction, gas-based deep reduction and synchronous cooling

A gas-based, carbon-thermal technology, applied in waste gas treatment, climate sustainability, sustainable manufacturing/processing, etc., can solve the complex gas source isolation control system, low carbon-thermal reduction degree of pellets, and slow gas-based reduction rate and other problems, to achieve the effect of promoting gas-based reduction rate, good internal porosity, and fast carbon-thermal pre-reduction rate

Pending Publication Date: 2020-06-19
CENT IRON & STEEL RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In view of the above analysis, the embodiment of the present invention aims to provide an ironmaking method of carbothermal pre-reduction, gas-based deep reduction and synchronous cooling to solve the problem of low carbon-thermal reduction degree of pellets, slow gas-based reduction rate, The long cooling time and the different gas sources in the reduction stage and the cooling stage during gas-based reduction lead to complex problems in the gas source isolation control system

Method used

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  • Iron-making method adopting carbothermal pre-reduction, gas-based deep reduction and synchronous cooling
  • Iron-making method adopting carbothermal pre-reduction, gas-based deep reduction and synchronous cooling
  • Iron-making method adopting carbothermal pre-reduction, gas-based deep reduction and synchronous cooling

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Experimental program
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Effect test

Embodiment 1

[0044] Guohai Sand Vanadium Titanium Magnetite, TFe content is 56%, chemical composition is shown in Table 1, ore powder particle size is less than 80 mesh.

[0045] The chemical composition (%) of table 1 sea sand vanadium-titanium magnetite

[0046] TF FeO Fe 2 o 3

TiO 2

V 2 o 5

SiO 2

CaO MgO Al 2 o 3

K Na Cl 56 21.85 56 10.67 0.76 4.29 0.72 3.18 4.12 <0.1

<0.1

<0.05

[0047] After uniformly mixing the vanadium-titanium magnetite and the binder, the carbon-containing pellets are prepared by a double-roller briquetting machine. 10kg of pellets were placed in a vertical reduction furnace and heated with H 2 It is a reducing gas, which is reduced at 900°C for 4 to 10 hours, and N is introduced after the reduction is completed. 2 Cool to 4h. The reduced pellets were crushed and ground to prepare powder samples, and the metallization rate of the samples was determined by chemical titration analysi...

Embodiment 2

[0050] Use the same vanadium-titanium magnetite raw material as above. After uniformly mixing the vanadium-titanium-magnetite, the binder, and the coal powder, the carbon-containing pellets are prepared by a double-roller briquetting machine, and the pellets have a C / O ratio of 1.2. The chemical composition of coal powder is shown in Table 2.

[0051] Table 2 Chemical composition of anthracite powder for reduction, %

[0052] composition(%) fixed carbon Volatile matter Ash S moisture anthracite 74.53 5.16 17.86 0.44 2.45

[0053] Put 10kg of carbon-containing pellets in an electrically heated small rotary hearth furnace for heating, and reduce them at 1250°C for 15-30 minutes to simulate the carbothermal reduction process of carbon-containing pellets. The reduced pellets were crushed and ground to prepare powder samples, and the metallization rate of the samples was determined by chemical titration analysis.

[0054] The experimental results...

Embodiment 3

[0056] In this example, the carbon-containing scout prepared in Example 1 is used for pre-reduction, deep reduction and synchronous cooling.

[0057] Place 10kg of carbon-containing pellets in a small rotary hearth furnace for heating, pre-reduce at 1250°C for 15 minutes and 20 minutes, stop heating after the reduction, and discharge the hot metallized pellets into the vertical reduction through the discharger after the reduction Cooler, into H 2 Reduction cooling 4h, H 2 The flow rate is 50L / min, H 2 The gas volume to pellet mass ratio is 1.2 Nm 3 / kg.

[0058] The high-temperature gas after reduction and heat exchange is heat exchanged by the waste heat boiler to prepare supersaturated steam for power generation. The temperature of the gas after heat exchange by the waste heat boiler is 200°C, and then cooled to below 50°C by a water cooler, and the cooled gas passes through a dehumidifier After dehumidification, return to the vertical reduction cooler for recycling, and...

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Abstract

The invention relates to an iron-making method adopting carbothermal pre-reduction, gas-based deep reduction and synchronous cooling, and belongs to the field of non-blast furnace ironmaking. The problems of low carbon thermal reduction degree, low gas-based reduction rate and long cooling time of existing pellets and complex gas source isolation control system due to different gas sources of a reduction section and a cooling section during gas-based reduction are solved. The iron-making method adopting carbothermal pre-reduction, gas-based deep reduction and synchronous cooling comprises thefollowing steps that 1, the carbon-containing pellets are subjected to pre-reducing by using a rotary hearth furnace to obtain porous pre-reduced metalized pellets; 2, the porous pre-reduced metalizedpellets are discharged into a vertical reduction cooling reactor in a hot state, and subjected to countercurrent reduction and heat exchange with cold-state reducing gas; and 3, the high-temperaturegas subjected to reduction and heat exchange is subjected to heat exchange through a waste heat boiler, physical heat is utilized, and after the cooled gas is dehumidified and subjected to impurity removal, unreacted reducing gas returns to the vertical reduction cooling reactor to be recycled. According to the method, the high reduction degree effect that the pellet metallization rate is larger than 90% within 3 h-5 h is achieved.

Description

technical field [0001] The invention relates to the field of non-blast furnace ironmaking methods, in particular to an ironmaking method comprising carbothermal pre-reduction, gas-based deep reduction and synchronous cooling. Background technique [0002] Blast furnace ironmaking is the main method of ironmaking in my country, accounting for the absolute share of my country's iron production, but there are two characteristics of blast furnace smelting, one is to ensure the air permeability of the blast furnace, there must be a coke layer, the price of coke is high, and the coking process is seriously polluted by the environment The second is that the strength of the raw materials is high, and clinker is mainly used to enter the furnace, including sintered ore or oxidized pellets, which increases the cost of smelting and produces a large amount of tail gas, which increases the cost of treatment. Non-blast furnace ironmaking does not use sinter or oxidized pellets as raw materi...

Claims

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Application Information

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IPC IPC(8): C21B13/08C21B13/02
CPCC21B13/02C21B13/08C21B13/029C21B2100/66
Inventor 张俊周和敏齐渊洪严定鎏
Owner CENT IRON & STEEL RES INST
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