An intensified method for denitrification by ammonia spraying in the production process of iron ore pellets

A pelletizing and iron ore technology, which is applied in the strengthening field of ammonia injection denitrification in the production process of iron ore pellets, can solve the problems of prolonging the denitrification reaction time, short reaction time of iron-containing minerals, and low denitrification efficiency, so as to improve the denitrification efficiency , Improve dehydration efficiency and reduce adverse effects

Active Publication Date: 2022-02-18
ANSTEEL GRP MINING CO LTD
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Problems solved by technology

[0006] The purpose of the present invention is to provide a method for strengthening the production of iron ore pellets and denitrification by ammonia spraying. By adding additives, the burst temperature of the pellets is increased, the process parameters are optimized, and the denitrification reaction time is prolonged to solve the problem of NOx and NH in the prior art. 3 Short reaction time with iron-containing minerals in pellets and low denitrification efficiency

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  • An intensified method for denitrification by ammonia spraying in the production process of iron ore pellets

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Embodiment 1

[0026] Add the anti-burst additive in bentonite, the ratio is 1% of bentonite, additive is sodium carboxymethyl starch: cationic polyacrylamide: the compound of sodium carboxymethyl cellulose, the ratio of the three is 2:3:5, will Mix bentonite and additives thoroughly, then add 1.2% to iron concentrate to prepare pellets, the bursting temperature of green pellets is increased from 480°C to 600°C; the chain grate-rotary kiln pellet production process is adopted, and the thickness of the material layer is 240mm , the speed of the grate machine is 2.3m / min, the drying of the pellets adopts two-stage drying, the first stage is blast drying, the temperature is increased from the conventional 180°C to 250°C, and the dehydration rate of the first stage of the drying is increased from 32%. to 50%; Stage II is exhaust drying, the drying temperature is 350°C, and the wind speed is reduced from the conventional 1.2m / s to 1.0m / s. Pipelines are installed in the fume hood of the drying sec...

Embodiment 2

[0028] Add the anti-burst additive in bentonite, the ratio is 3% of bentonite, additive is sodium carboxymethyl starch: cationic polyacrylamide: the compound of sodium carboxymethyl cellulose, the ratio of the three is 4:4:7, will The bentonite and additives are fully mixed, finely ground and modified, and then 1.2% is added to the iron concentrate to prepare pellets. The burst temperature of the green pellets is increased from 480°C to 660°C; the chain grate-rotary kiln pellet production process is adopted, The thickness of the material layer is 280mm, the speed of the grate machine is 2.0m / min, the drying of the pellets adopts two-stage drying, the first stage is blast drying, the temperature is increased from the conventional 180°C to 300°C, and the first stage of drying is dehydrated The drying rate is increased from 32% to 59%; the second stage is exhaust drying, the drying temperature is 350°C, and the wind speed is reduced from the conventional 1.2m / s to 0.8m / s. Pipelin...

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Abstract

The invention discloses an intensified method for denitrification by ammonia injection in the production process of iron ore pellets. The method is to prepare pellets with high bursting temperature and good thermal stability by adding anti-burst additives to the pellet binder bentonite. In this way, the thickness of the material layer in the heat treatment process of the pellets is increased by 1.5 to 1.75 times, the machine speed is reduced to 4 / 7 to 2 / 3, and the exhaust wind speed in the second drying section is reduced to 0.8 to 1.0m / s. Ammonia water is evenly sprayed into the air stream for denitrification. The advantages of the present invention are: due to the operation of the thick material layer and the reduction of the airflow velocity, the time for the airflow to pass through the pellet material layer is prolonged, and the concentration of iron-containing minerals and NOx, NH in the denitrification catalyst is improved. 3 The action time is longer, thereby enhancing the efficiency of ammonia spray denitrification in the drying section, and the NOx removal rate is increased by 15% to 30%.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgical pellet technology, and in particular relates to a strengthening method for ammonia injection denitrification in the production process of iron ore pellets. Background technique [0002] NOx is considered to be a powerful greenhouse gas, and it is also the main factor causing the "ozone hole", photochemical smog and acid rain, which is extremely harmful to the ecological environment. [0003] The steel industry produces a large amount of flue gas, which emits particulate matter, SO 2 , NOx and other pollutants. Although the steel industry has made great progress in dust removal and desulfurization, the prevention and control of NOx pollution is still in its infancy. According to research at home and abroad, the NOx emitted by the flue gas produced by iron ore sintering and pelletizing ranks first in iron and steel enterprises, accounting for more than 50%. In recent years, my...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B1/243C22B1/20B01D53/86B01D53/56
CPCC22B1/2406C22B1/243C22B1/20B01D53/8625B01D2258/0283B01D2251/2062
Inventor 朱德俊范晓慧陈许玲甘敏张海峰翁兴洋黄旭季志云
Owner ANSTEEL GRP MINING CO LTD
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