Method for smelting bell-less top blast furnace high proportion pellet ore burden structure

Abstract

The invention discloses a method for smelting a bell-less top blast furnace high proportion pellet ore burden structure. Alkalinity of sintering ore is improved to be 2.5-3.5 times or flux with high CaO content is added, the technology that bulk coke is charged at the center and coke is mixed in ore is adopted, a charging method of split charging, ore coke unequal stockline and chute feeder feeding from small angle to high angle is adopted, a tank is reversed regularly, and batch weight of ore is expanded, so that a blast furnace stock column can maintain stable and uniform edge gas flow and strong center gas flow when gas flow passes through; the tuyere theoretical combustion temperature is controlled to be 2200-2300 DEG C; and the operation policy of low silicon and low slag basicity is adopted to smelt. The utilization factor of the blast furnace can be improved by 8-10%; the fuel ratio of the blast furnace can be reduced by 2-3%; and the Si content of pig iron is reduced, the desulphuration capacity is improved, the pig iron quality is improved, the furnace body service life is prolonged to more than eight years, and the blast furnace production stability and the economic benefit are improved. The invention is applicable to the bell-less top blast furnace under the condition that pellet ore in the blast furnace burden structure accounts for 60-100% of the total burden quantity.

Description

technical field [0001] The invention belongs to a blast furnace smelting process, in particular to a bellless furnace top blast furnace high-proportion pellet furnace charge structure smelting method. Background technique [0002] Due to the expansion of the blast furnace in the ironworks and the demand for intensified smelting, the contradiction of increasing the clinker rate of the blast furnace has become increasingly prominent. In order to ensure the clinker rate of the blast furnace and improve the comprehensive grade of the blast furnace. Under the original sintering production capacity, develop the production of pellets, so that the proportion of pellets in the blast furnace reaches about 80%; due to the particularity of the pellets themselves, after the amount of pellets increases to 60% , it is difficult to ensure the smooth production of the blast furnace, the number of collapsed and suspended materials increases, and the phenomenon of thickening of the furnace wai...

AI Technical Summary

Problems solved by technology

Under the original sintering production capacity, develop the production of pellets, so that the proportion of pellets in the blast furnace reaches about 80%; due to the particularity of the pellets themselves, after the amount of pellets increases to 60% , it is difficult to guarantee the smooth production of the blast furnace, the number of collapsed and suspended materials increases, and the phenomenon of thickening of the furnace waist and bosh often occurs, which seriously restricts the production of the blast furnace and the improvement of technical and economic indicators

[0003] For the smelting of high-proportion pellet furnace charge structure of bellless furnace top blast furnace, there is no good solution at home and abroad at present; because when the proportion of pellet ore accounts for more than 60% of the total charge, there are the following outstanding problems that need to be solved during smelting Questions: (1) Because most of the pellets are acidic, namely: CaO% / SiO 2 %<1.00, it is necessary to consider how CaO is added in the batching of the blast furnace; (2) The natural pile angle of pellets is smaller than that of coke, only 24-27°, and the rolling property is good, and the angle of repose is small; After the pellets are added to the blast furnace, they are easy to roll, making the material surface tend to be flat; (3) The pellets in the blast furnace are more severely reduced and pulverized in the temperature range of 570-1000°C, and the pulverization rate is about 30%-35%; Under normal circumstances, there is a volume expansion rate of 20%-25%, which seriously affects the air permeability of the blast furnace material column.

(4) The initial softening temperature of pellet load reduction softening is relatively low, and the softening range is relatively wide, which causes the resistance of blast furnace bosh gas to pass through the reflow zone to increase

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