CN111304386A

CN111304386A - Method for promoting zinc in blast furnace

Info

Publication number: CN111304386A
Application number: CN202010165704.XA
Authority: CN
Inventors: 白文广; 渠世平; 高东辉
Original assignee: Baotou Iron and Steel Group Co Ltd
Current assignee: Baotou Iron and Steel Group Co Ltd
Priority date: 2020-03-11
Filing date: 2020-03-11
Publication date: 2020-06-19

Abstract

The invention discloses a method for promoting blast furnace zinc, which mainly promotes the blast furnace zinc by controlling the coke ratio in the center of a blast furnace to be 31.25-37.5%. The invention can promote the zinc in the blast furnace and reduce the zinc element circulation enrichment in the furnace.

Description

Method for promoting zinc in blast furnace

Technical Field

The invention relates to a method for promoting zinc in a blast furnace.

Background

In recent years, in order to reduce the smelting cost of the blast furnace, a large amount of economic materials are used, the zinc load of the blast furnace is increased, and zinc flows out from a tuyere in the damping down process. Under the condition that a large amount of harmful elements are increased when economic materials are used for feeding into a furnace, how to improve the discharge rate of potassium, sodium and zinc, reduce the cyclic enrichment of the harmful elements and reduce the influence of the potassium, the sodium and the zinc on the smooth operation of the furnace condition and the service life of the blast furnace is imperative.

The hazard of zinc in blast furnaces is manifested in three ways: firstly, the brick lining of the blast furnace is damaged, and the service life of the blast furnace is influenced. The zinc vapor enriched in the furnace can permeate into the furnace wall to be combined with the furnace lining, and the zinc vapor permeates into the lining joints and pores of the furnace lining to be deposited, oxidized and expanded in volume, so that the furnace lining is damaged; the tuyere is enriched, oxidized and expanded in the tuyere composite brick, so that the tuyere is upwarped. Secondly, the smooth operation of the blast furnace is influenced. The zinc vapor is condensed on the surface of the material block to form a film of zinc metal or oxide, which can weaken the metallurgical properties of coke and ore and reduce the strength and reducibility of the material block; after zinc steam is condensed at the upper part of the blast furnace, if the zinc steam is adhered to a furnace wall, nodulation is easily formed, if the zinc steam is adhered to furnace burden, air holes of the furnace burden are blocked, the air permeability of a material column is deteriorated, and the smooth operation of the blast furnace is influenced; the zinc vapor rises along with the coal gas flow, is condensed and deposited in the ascending pipe to form zinc nodules, and the ascending pipe is plugged to influence the distribution of the coal gas flow. Thirdly, increasing the coke ratio. The zinc circulation in the blast furnace transfers the heat in the high temperature area in the furnace to the low temperature area, and increases the coke ratio.

No effective zinc removal method is available in the available data.

Disclosure of Invention

The invention aims to provide a method for promoting blast furnace zinc, which can promote the blast furnace zinc and reduce the cyclic enrichment of zinc elements in a furnace.

In order to solve the technical problems, the invention adopts the following technical scheme:

a method for promoting zinc in blast furnace features that the coke ratio in the center of blast furnace is controlled to 31.25-37.5%.

Further, the center coke ratio was changed by changing the charging system of the blast furnace.

Further, the blast furnace is 4150m³A blast furnace.

Compared with the prior art, the invention has the beneficial technical effects that:

① promoting zinc discharge of blast furnace, reducing the cyclic enrichment of new elements in furnace, ② eliminating metallic zinc enriched in tuyere, ③ reducing the damage of zinc to furnace lining and tuyere, ④ prolonging the period of blast furnace.

Drawings

FIG. 1 shows 4150m³The Z/W value of the blast furnace and the ash amount are in corresponding relation.

Detailed Description

As can be seen from the research and calculation of the zinc balance, 95% of the zinc in the blast furnace can be discharged out of the furnace along with the gas, so that the central gas amount can be increased by increasing the central coke amount, thereby promoting the discharge of the zinc element, but the increase of the gas amount can increase the fuel ratio of the blast furnace and the production cost, so that the discharged gas amount should be controlled within a certain range.

TABLE 1 ladle steel 4150m³Blast furnace specimen zinc content/%)

According to the zinc content of each sample in Table 1, 4150m was combined³The results of the zinc balance and distribution calculation of the production data of the blast furnace are shown in Table 2, in which the data are the average values of various types.

TABLE 2 ladle steel 4150m³Blast furnace specimen zinc distribution and balance

Note: the absolute error is 524.86-471.44-53.42 g/t, and the relative error is 53.42/499.50-10.69%

The zinc load of the blast furnace is 524.86g/t, the zinc quantity carried by the sinter and the pellet is the most, and the zinc quantity accounts for 95.41 percent of the total zinc quantity in the furnace; the high zinc content in the sinter and the pellet and the high charging proportion directly cause the zinc to be a main source of the charging zinc load. Therefore, the zinc content of the sinter and the pellet is controlled to be reduced by 4150m³The key of the furnace charging zinc load of the blast furnace.

In the branch, the zinc amount taken away from the blast furnace by the gas ash is the largest, which accounts for 95.01% of the total expenditure, and the zinc content in the cloth bag ash is the highest, and the gravity ash and the cyclone ash are the second.

The zinc balance is calculated according to the income and expenditure, the absolute error is 53.42g/t, the relative error is 10.69 percent, and the error is mainly considered to be the circulating enrichment amount of zinc in the blast furnace.

According to the support proportion, in order to reduce the cyclic enrichment of the zinc element in the blast furnace, the zinc can be discharged by increasing the coal gas amount. Through tests, the corresponding relation between the Z/W value and the ash amount of the blast furnace top gas is shown in figure 1.

As can be seen from figure 1, the Z/W value of the gas can represent the central gas amount, and the Z/W values of the zinc discharge amount and the top gas are positiveAnd (4) the ratio. When the central coke amount is increased, the central gas amount is increased, and the zinc amount of the blast furnace is increased along with the central gas amount. By wrapping steel 4150m³The comparative relationship between the central coke amount and the zinc discharge amount obtained from the test data of the blast furnace in the last two years is shown in Table 3.

TABLE 3 ladle steel 4150m³Blast furnace center coke amount and zinc discharge amount comparison table

From the analysis in Table 3, it can be seen that ① ladle steel 4150m³When the proportion of coke in the center of the blast furnace is less than 31.25 percent, metal zinc flows out of a tuyere and the times of abnormality of furnace conditions are more; when the central coke proportion reaches 31.25%, the zinc metal at the tuyere disappears, the abnormal times of the furnace condition are obviously reduced, and the fuel ratio is 556kg/t and is in a reasonable level. When the proportion of the central coke is more than 37.5, no metal zinc flows out of the tuyere, the smooth running state of the furnace is good, but the fuel ratio is greatly increased (575kg/t) due to the great reduction of the utilization rate of the coal gas, and the cost of the pig iron is increased. Therefore, the central coke proportion is controlled at a level of 31.25 percent, and the zinc discharging effect and the economic index of the blast furnace are optimal.

In the invention, the proportion of the central coke is controlled to be 31.25-37.5%, and the zinc discharging efficiency can reach 95% of the zinc load of the furnace.

The invention controls the central coke proportion at 31.25% -37.5% level, and the fuel ratio can be kept at reasonable level.

The invention controls the central coke proportion to be 31.25-37.5%, which is beneficial to the smooth operation of the furnace condition and reduces the number of abnormal furnace conditions.

Note: and the Z/W value of the coal gas can represent the quantity of the central coal gas. The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.

Claims

1. A method for promoting zinc in a blast furnace is characterized by comprising the following steps: the coke proportion of the blast furnace center is controlled to be 31.25-37.5%.

2. The method for promoting zinc in a blast furnace according to claim 1, wherein: the center coke ratio was changed by changing the charging schedule of the blast furnace.

3. The method for promoting zinc in a blast furnace according to claim 1, wherein: the blast furnace is 4150m³A blast furnace.