Method and system for treating metallurgical slag

Abstract

The invention discloses a method and system for treating metallurgical slag. The method comprises the steps that the metallurgical slag, limestone and adhesives are subjected to forming treatment, so that first material pellets are obtained; oxidizing roasting is conducted on the first material pellets, so that fayalite in the metallurgical slag is converted into ferric oxide, and meanwhile oxidizing roasting products are obtained through desulfurization; the oxidizing roasting products are crushed, so that crushed oxidizing roasting products are obtained; the crushed oxidizing roasting products, reducing coal, the adhesives and water are subjected to forming treatment, so that second material pellets are obtained; reducing roasting is conducted on the second material pellets, so that the iron oxide in the second material pellets is converted into iron, and meanwhile reducing roasting products are obtained through desulfurization; and ore grinding and magnetic separation are conducted on the reducing roasting products, so that metal iron powder and tailings are obtained. By the adoption of the method, the problem that reduction of fayalite in the metallurgical slag is difficult is solved, effective separation of the iron element is achieved, and high-quality low-sulfur metal iron powder can be obtained advantageously.

Description

technical field [0001] The invention belongs to the technical field of metallurgical industry, in particular to a method and system for processing metallurgical slag. Background technique [0002] In the prior art, with the development of society and economy, the production and consumption of non-ferrous metals are also increasing day by day. Along with the smelting process of non-ferrous metal products, a large amount of smelting slag and tailings are also discharged. Most of these smelting slags are high-temperature molten slags obtained by pyrometallurgy. In order to recover the valuable elements in them, some smelting slags are quenched in water to room temperature and then crushed with chemicals for flotation to finally obtain smelting furnace slag ore dressing tailings. . These smelting slags and beneficiation tailings generally contain 35-55 wt% iron, mainly in fayalite phase. Due to the difficulty in utilizing smelting slag and tailings, a large amount exists in t...

AI Technical Summary

Problems solved by technology

When the carbon-containing pellets are reduced at a temperature greater than 1200 °C, the metallurgical slag melts to separate the reduced coal and slag, which deteriorates the reaction kinetics; when the reaction temperature is higher, such as above 1450 °C, it belongs to smelting reduction, although it can be reduced, However, the energy consumption is too high; if the reduction temperature is lower than the melting point of the metallurgical slag, although the pellets will not melt, the metallurgical slag will fully contact the reduced coal, but fayalite is difficult to restore, the reduction speed is slow, and the reduction is not complete

[0004] In addition, non-ferrous metallurgical slag contains 0.5%-1.5% sulfur, and reduced coal contains >0.5% sulfur. During the reduction process, most of the sulfur brought by the two raw materials enters the metallized pellets. Only a small part of sulfur can be removed, so that the sulfur content of iron powder is as high as 0.5%, which is higher than the requirements for steelmaking pig iron, which is not conducive to the subsequent steelmaking process. If the desulfurization process is added, the production cost will be increased.

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