Red mud treatment method and system

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...

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.

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