A Method for Improving the Air Permeability of All-fine Powder Sintered Material Layer

Abstract

The invention discloses a method for improving the air permeability of a fully refined powder sintered material layer, relates to the field of steel smelting, in particular to the field of fully refined powder sintered ore. The method comprises the steps that sintering return mines are adopted as granulating balls, are subjected to primary fully refined powder batching mixing, secondary fully refined powder batching mixing, and tertiary fully refined powder batching mixing sequentially, then enter a material loosening device, come out of the material loosening device, and then enter a sintering process. Before being subjected to the primary fully refined powder batching mixing, the sintering return mines are subjected to pre-wetting with atomized water till the water content reaches 4-6%.

Description

technical field [0001] The invention relates to the field of iron and steel smelting, in particular to the field of all-concentrated powder sintered ore. Background technique [0002] The air permeability of the sinter layer is a key technical parameter affecting the sintering process index, sinter output and quality, and the air permeability is closely related to the properties of raw materials and the control of production parameters. Full refined powder, TISCO uses two kinds of iron fine powder for full fine powder sintering, one is magnetite concentrate, the other is hematite concentrate, the particle size of magnetite concentrate is less than 0.074mm and the content reaches more than 96%, hematite concentrate The concentrate particle size is less than 0.045mm and the content reaches more than 98% (full concentrate powder in the present invention refers to the remaining iron concentrate powder after material selection and grinding). The characteristics of raw materials ...

AI Technical Summary

Problems solved by technology

Full refined powder, TISCO uses two kinds of iron fine powder for full fine powder sintering, one is magnetite concentrate, the other is hematite concentrate, the particle size of magnetite concentrate is less than 0.074mm and the content reaches more than 96%, hematite concentrate The concentrate particle size is less than 0.045mm and the content reaches more than 98% (full concentrate powder in the present invention refers to the remaining iron concentrate powder after material selection and grinding). The characteristics of raw materials for sintering determine that the granulation effect of the mixture is poor, the air permeability of the material layer is significantly reduced, and the negative pressure of sintering is increased.

The air permeability of the material layer becomes poor, resulting in uneven sintering air volume and heat distribution, the formation and diffusion of liquid phase are inhibited, the degree of homogenization of sinter ore is low, and the particle size composition of sinter ore deteriorates, the -5mm powder rate increases significantly, and the drum strength decrease, the FeO content increases, which is not conducive to the blast furnace smelting sequence

[0003] Under the working condition of all-fine powder sintering, the requirements for the unwinding device are higher, but the traditional unloading device is a fixed cylindrical and plate-shaped loosening rod. The viscosity is high, and at the same time, the moisture content of the mixture for sintering with all-fine powder is higher than that for sintering with rich ore powder. Severe sticking phenomenon will appear on the upper part of the loosener, resulting in excessive deviation of the lateral air permeability of the sintered material layer, and the combustion zone is wavy, which will lead to poor quality of sintered ore. When the material sticks to the unwinder, it may even cause the sintered material layer to be sandwiched, endangering the safety of the finished product belt at the rear of the sintering system.

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