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Red mud treatment method and system

A technology for red mud and dealkalized red mud, applied in the fields of metallurgy and energy, can solve problems such as unfavorable separation of slag and iron, unsmooth production, serious adhesion between reflow and refractory materials, etc., and achieve important economic and social benefits, realize The effect of comprehensive recycling and accelerated reduction efficiency

Inactive Publication Date: 2016-11-16
JIANGSU PROVINCE METALLURGICAL DESIGN INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When no limestone is added or the amount added is small, the pellets cannot be fully reduced, and the metallization rate is very low, which is not conducive to the subsequent separation of slag and iron.
When more limestone is added, CaO in limestone reacts with FeO and SiO at high temperature 2 、Al 2 o 3 The formation of low melting point compounds such as calcium ferrite olivine leads to severe bonding between the pellets and refractory materials, so it is difficult to obtain metallized pellets with high metallization rate. The existing rotary kiln adopts red mud powder sintering method. Although the dealkalization rate can reach more than 60%, the metallization rate is only 50%-70%, and the iron recovery rate is 30%. The equipment is easy to loop and the production is not smooth.

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0055] A certain red mud, TFe is 30.29%, Na 2 O is 5.22%. The red mud is dried and finely ground to -0.043mm, and the red mud ore powder is sent into the fluidized bed for pre-reduction dealkalization. In the fluidized bed reducing gas (H 2 +CO) was 55%, the gas temperature was 1020° C., and the reaction time was 40 minutes. The sodium content of the red mud after dealkalization is 0.39%. After dealkalization, the red mud is mixed with 18% reduced coal and 5% limestone. After mixing evenly, briquetting is carried out, and the obtained agglomerates are placed in a rotary hearth furnace for reduction. The reduction temperature in the rotary hearth furnace was 1200° C., and the reduction time was 25 minutes to obtain metallized pellets with a metallization rate of 92%. Metallized pellets are subjected to grinding and magnetic separation to obtain metal iron powder with TFe93.5%.

Embodiment 2

[0057] A certain red mud, TFe is 30.29%, Na 2 O is 5.22%. The red mud is dried and finely ground to -0.037mm, and the red mud ore powder is sent into the fluidized bed for pre-reduction dealkalization. In the fluidized bed reducing gas (H 2 +CO) was 60%, the gas temperature was 950° C., and the reaction time was 35 minutes. The sodium content of the red mud after dealkalization is 0.35%. After dealkalization, the red mud is mixed with 10% reduced coal and 5% limestone. After mixing evenly, it is pressed into blocks, and the obtained lumps are placed in a rotary hearth furnace for reduction. The reduction temperature in the rotary hearth furnace was 1250° C., and the reduction time was 25 minutes to obtain metallized pellets with a metallization rate of 93%. Metallized pellets are subjected to grinding and magnetic separation to obtain metal iron powder with TFe93.8%.

Embodiment 3

[0059] A certain red mud, TFe is 30.29%, Na 2 O is 5.22%. The red mud is dried and finely ground to -0.037mm, and the red mud ore powder is sent into the fluidized bed for pre-reduction dealkalization. In the fluidized bed reducing gas (H 2 +CO) was 60%, the gas temperature was 850° C., and the reaction time was 40 minutes. The sodium content of the red mud after dealkalization is 0.55%. After dealkalization, the red mud is mixed with 12% reduced coal and 3% limestone. After mixing evenly, it is pressed into blocks, and the obtained lumps are placed in a rotary hearth furnace for reduction. The reduction temperature in the rotary hearth furnace was 1250° C., and the reduction time was 25 minutes to obtain metallized pellets with a metallization rate of 93%. Metallized pellets are subjected to grinding and magnetic separation to obtain metal iron powder with TFe92.5%.

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Abstract

The invention discloses a method and system for treating red mud, wherein the method for treating red mud includes: drying the water-containing red mud to obtain dried red mud; finely grinding the dried red mud to obtain ultra-fine red mud Fine powder; red mud superfine powder is pre-reduced and dealkalized in a fluidized bed under a reducing atmosphere to obtain dealkalized red mud and high-alkali dust; dealkalized red mud is mixed with reducing agents and additives , in order to obtain red mud agglomerates; direct reduction treatment of red mud agglomerates in a rotary hearth furnace in order to obtain metallized pellets; and conduct grinding and magnetic separation of metallized pellets in order to obtain iron powder and tailings scum. Therefore, the method can effectively remove alkali metals in red mud, and solve the technical problems of low dealkalization rate of red mud, poor iron reduction effect and difficult iron recovery. At the same time, by adding additives, the iron particles are reduced and aggregated, which facilitates the subsequent separation of slag and iron through physical separation.

Description

technical field [0001] The invention belongs to the technical field of metallurgy and energy, and in particular relates to a method and system for processing red mud. Background technique [0002] Red mud is the most important solid waste generated in the production process of alumina industry. At present, the annual discharge of red mud in China exceeds 30 million tons. Except for a small part used in cement production and brick making, most of them are used in wet open-air dam construction Stockpiling, the cumulative stockpiling of red mud has exceeded 350 million tons. In the field of cement building materials, my country's cement consumption in 2015 was about 2.2 billion tons, and the market is very huge. However, the main limiting factor restricting the application of red mud in cement is the high alkali content in red mud. The existing red mud dealkalization methods mainly include lime method, atmospheric suspension carbonization method, water washing method, and pick...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21B13/00C22B1/24C22B1/00
CPCC21B13/0046C21B13/008C22B1/00C22B1/24
Inventor 王敏曹志成薛逊吴佩佩吴道洪
Owner JIANGSU PROVINCE METALLURGICAL DESIGN INST
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