Method for inhibiting reduction degradation of zinc-containing dust pellets in rotary hearth furnace

Abstract

The invention discloses a method for inhibiting reduction degradation of zinc-containing dust pellets in a rotary hearth furnace. The method comprises the steps as follows: 1), zinc-containing dust and bentonite are pneumatically transported to a stock bin and mixed, and a mixture is formed and divided into two parts by a distributor; 2), after part of the mixture and a composite additive are mixed uniformly, the obtained mixture is fed into a No.1 ball press machine and pressed into No.1 pellets to be sent into a drier, and the dried No.1 pellets are distributed into the rotary hearth furnacethrough a No.1 vibrating distributor; 3), the other part of mixture is sent into a No.2 ball press machine and pressed into No.2 pellets to be sent into the drier, and the dried No.2 pellets are distributed into the rotary hearth furnace through a No.2 vibrating distributor; and 4), the reduction process of the pellets distributed at the bottom of the rotary hearth furnace is completed in the rotary hearth furnace. The problem about the reduction degradation of the zinc-containing dust in the rotary hearth furnace is thoroughly solved from the source.

Description

technical field [0001] The invention relates to a process for returning metallized pellets obtained by treating zinc-containing dust in a rotary hearth furnace to a blast furnace, a converter / electric furnace or a sintering process, and more specifically, to a method for inhibiting the reduction and pulverization of zinc-containing dust pellets in a rotary hearth furnace. Background technique [0002] my country's annual crude steel output is about 800 million tons, and the total amount of iron and steel dust is generally 8% to 12% of steel output. Calculated at 10%, the total is about 80 million tons, including about 20 million tons of zinc-containing dust, which is rich in iron and zinc. and carbon elements. Zinc-containing dust is returned to the sintering process, and the zinc in it will corrode the furnace lining, cause nodules in the blast furnace, affect the smooth operation of the blast furnace, and seriously cause the shutdown of the blast furnace. Therefore, realiz...

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Problems solved by technology

[0008] 1) It will reduce the finished metallized pellets (oversize) produced by the rotary hearth furnace and reduce the system productivity;

[0009] 2) Due to the pulverization of zinc-containing dust pellets during the reduction process in the furnace, the specific surface area in contact with the flue gas is increased, causing a large amount of carbon in them to be burned, which does not play a role in reduction, thus causing its metallization rate And the dezincification rate is reduced, and the product quality is deteriorated;

[0010] 3) Iron and steel enterprises all hope that the metallized pellets discharged from the rotary hearth furnace can be directly sent to blast furnace ironmaking or converter / electric furnace steelmaking. invest;

[0011] 4) Due to the low metallization rate and high zinc content of the undersieve, even if it is given to the blast furnace for free for sintering, the blast furnace ironworks are unwilling to use it, which directly reduces the economic benefits;

[0012] 5) If the undersieve is not disposed of in time, even if it is stored on site for several hours, due to its large specific surface area, the reduced iron is very easy to oxidize and generate heat, resulting in spontaneous combustion, which not only pollutes the environment, but also poses a great safety hazard

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