Method for modifying iron ore powder by composite additive to prevent sticking and defluidizing during fluidization reduction

A composite additive and iron ore powder technology, applied in the direction of fluidized bed furnace, etc., can solve the problems of low metallization rate, inability to operate continuously in the reduction process, failure to meet the requirements of hot briquetting, etc. The effect of improving reduction efficiency and good anti-sticking effect

Inactive Publication Date: 2013-02-13
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The technical problem solved by the invention: Aiming at the technical problems that the reduction process cannot be continuously operated due to phenomena such as iron ore powder fluidization reduction process, such as mineral powder sticking and loss of flow, and the metallization rate is low and cannot meet the requirements of hot briquetting, an additive is provided A method for preventing caking loss in the fluidized reduction process of modified iron ore powder, which can reduce the occurrence of caking loss, improve reduction efficiency and product metallization rate, and achieve the purpose of efficient continuous production

Method used

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  • Method for modifying iron ore powder by composite additive to prevent sticking and defluidizing during fluidization reduction
  • Method for modifying iron ore powder by composite additive to prevent sticking and defluidizing during fluidization reduction

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Embodiment 1

[0027] An iron ore powder with a particle size of less than 70 meshes is added with composite additives calcium nitrate and aluminum nitrate (mass ratio 1:1), the concentration of the additive solution is 20%, and the mass ratio of the solution to the iron ore powder is 3:1. After stirring, impregnating, After drying, the modified iron ore powder is placed in a fluidized bed for fluidized roasting and pre-reduction, and then the reduction temperature in the fluidized bed is 800 ° C, and the reducing gas is H 2 =20%, CO=80%, and the final reduction is carried out under the condition of air velocity of 0.5m / s. The pre-reduction and final reduction process can be normally fluidized, the pressure difference of the fluidized bed remains constant, the fluidization state is normal, and the metallization rate can reach 73.70%, which is 30.45% higher than that without additives. The slag phase separated by magnetic separation is dissolved in nitric acid, filtered, and reconstituted int...

Embodiment 2

[0029] An iron ore powder with a particle size of less than 70 meshes is added with composite additives calcium nitrate and aluminum nitrate (mass ratio 1:2), the concentration of the additive solution is 40%, and the mass ratio of solution to iron ore powder is 3:1. After stirring, impregnating, After drying, the modified iron ore powder is placed in a fluidized bed for fluidized roasting and pre-reduction. Then the fluidized bed reduction temperature is 900°C, and the reducing gas is H 2 =20%, CO=80%, and the final reduction is carried out under the condition of air velocity of 0.5m / s. The pre-reduction and final reduction process can be normally fluidized, the pressure difference of the fluidized bed remains constant, the fluidization state is normal, and the metallization rate can reach 82.54%, which is 38.99% higher than that without additives. The slag phase separated by magnetic separation is dissolved in nitric acid, filtered, and reconstituted into a 40% additive sol...

Embodiment 3

[0031] An iron ore powder with a particle size of less than 70 meshes is added with composite additives magnesium nitrate and calcium nitrate (mass ratio 1:1), the concentration of the additive solution is 20%, and the mass ratio of the solution to the iron ore powder is 3:1. After stirring, impregnating, After drying, the modified iron ore powder is placed in a fluidized bed for fluidized roasting and pre-reduction. Then the fluidized bed reduction temperature is 800°C, and the reducing gas is H 2 =20%, CO=80%, and the final reduction is carried out under the condition of air velocity of 0.5m / s. The pre-reduction and final reduction process can be normally fluidized, the pressure difference of the fluidized bed remains constant, the fluidization state is normal, and the metallization rate can reach 78.43%, which is 34.88% higher than that without additives. The slag phase separated by magnetic separation is dissolved in nitric acid, filtered, and reconstituted into a 20% add...

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Abstract

The invention relates to a method for modifying iron ore powder by utilizing a composite additive to prevent sticking and defluidizing during fluidization reduction. The method comprises the following steps of: modifying the iron ore powder before a fluidization reduction process step, firstly preparing a 0.5%-60% additive solution, then dipping the iron ore powder in the additive solution, adsorbing the additive onto the surface of the iron ore powder or a pore canal by utilizing the adsorption performance of the iron ore powder, and performing fluidization preheating treatment on the modified iron ore powder. According to the method disclosed by the invention, the occurrence of sticking and defluidizing during the fluidization reduction can be effectively inhibited, and the reduction degree and the metallization rate are respectively improved by 45%-55% and 30%-40%. Simultaneously, the additive can realize cyclic utilization by magnetic separation so as to ensure product quality. The method disclosed by the invention has the advantages of a wide range of applications of ore, and capability of adjusting the composition of the composite additive against the characteristics of the type of the iron ore powder to achieve the best anti-sticking effect; and simultaneously, the process flow of the fluidization reduction process is not changed, and the method is simple to operate and economic and practical.

Description

technical field [0001] The invention belongs to the technical field of ironmaking production, and in particular relates to a method for modifying iron ore powder with compound additives to prevent cohesion loss in a fluidized reduction process and improve metallization rate. Background technique [0002] At present, the external compliance of my country's iron ore resources is about 60%, and the supply of iron ore resources has become a bottleneck. With the depletion of high-grade iron ore resources in the world, there are less and less natural rich ore and lump ore. Therefore, in order to solve the shortage of iron ore resources in our country, we must base ourselves on the utilization of low-grade and compound paragenetic ore resources. In particular, the grade of my country's iron ore resources is low. To meet the requirements of ironmaking grade, it needs to go through fine grinding, beneficiation and enrichment to produce fine iron fine powder. The particle size of iron...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21B13/00C22B1/02
Inventor 钟怡玮王志郭占成
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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