Metallurgical composite pelletizing prepared through twice pelletizing method, as well as preparation method and application thereof

Abstract

The invention provides a metallurgical composite pelletizing prepared through a twice pelletizing method, as well as a preparation method and an application thereof. The pelletizing is provided with a pelletizing shell formed by a central pelletizing core and a pellet material coating the outside of the pelletizing core. The internal pelletizing core of the formed pelletizing is in a reducing atmosphere, the outside of the formed pelletizing is in an oxidizing atmosphere, and the metallurgical composite pelletizing undergoing twice pelletizing satisfies the metallurgical requirements. The pelletizing core takes an iron-containing material and reducing coal dust or coke powder as raw materials in which adhesive and waste fly dust are added, and is obtained by means of disk pelletization or pressure pelletization. The pelletizing shell takes the iron-containing material and the pelletizing core as raw materials in which the adhesive is added, and is obtained by means of disk pelletization and taking the pelletizing core as the center of the sphere. Various metallurgical performance indexes of the composite pelletizing are highly better than normal pellets. The composite pelletizing not only realizes the harmlessness and the recycling of the waste fly ash, but also can greatly improve the technical and economic indexes of iron making blast furnaces. In addition, the composite pelletizing not only achieves such social benefits as energy conservation, emission reduction, environment protection and environment pollution treatment, but also can create considerable economic benefits.

Description

technical field [0001] The invention belongs to the technical fields of metallurgical iron-smelting and steel-making technology and waste treatment technology, and specifically relates to the production of pellets and sintered ore for metallurgical iron-making, the production of high-quality scrap steel and slag-forming agent for steel-making, and the pretreatment technology for waste fly ash. While improving the metallurgical properties, the harmless pretreatment of garbage fly ash can be realized. Background technique [0002] Metallurgical pellet is the latest mature technology widely used in the blast furnace-converter production process in the iron and steel metallurgy industry. It is one of the most important raw materials for blast furnace smelting. Compared with traditional sinter, it is suitable for all fine concentrates and has high strength. It has uniform viscosity, high grade and good reducibility, and its metallurgical properties greatly exceed that of sintered...

AI Technical Summary

Problems solved by technology

[0008] However, when melting treatment is performed in a high-temperature oxidizing atmosphere, when the melting temperature is above 800°C, all the trivalent chromium in the heavy metal will be converted into hexavalent chromium, and hexavalent chromium is a poisonous substance for swallowing / very toxic for inhalation, and skin contact may Causes sensitivity, more likely to cause hereditary gene defects, may cause cancer if inhaled, and has persistent danger to the environment, which is not allowed to exist in environmental protection standards at home and abroad

[0009] The use of high-temperature reducing atmosphere melting method can effectively avoid this problem, but the current high-temperature reducing atmosphere melting method at home and abroad all use special high-temperature reducing atmosphere melting equipment, such as surface melting furnace, arc melting furnace, plasma melting furnace, cyclone Furnaces, etc., the construction and operation costs of these equipment are extremely high, and it is difficult to implement industrialization

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