CN110643760A

CN110643760A - Ultrahigh Al2O3Blast furnace smelting method of furnace slag

Info

Publication number: CN110643760A
Application number: CN201910942502.9A
Authority: CN
Inventors: 刘杰; 姜喆; 朱建伟; 周明顺; 车玉满; 孙鹏; 郭天永; 姚硕; 李建军; 韩晓东
Original assignee: Angang Steel Co Ltd
Current assignee: Angang Steel Co Ltd
Priority date: 2019-09-30
Filing date: 2019-09-30
Publication date: 2020-01-03
Anticipated expiration: 2039-09-30
Also published as: CN110643760B

Abstract

The invention discloses an ultrahigh Al₂O₃The blast furnace smelting method of the furnace slag comprises 10-16% of MgO and Al by mass₂O₃30-40% of FeO and 1-2.5% of FeO; the binary basicity R2 of the slag is 0.8-0.9; controlling blast temperature of the blast furnace to be more than 1250 ℃; adding converter slag into pulverized coal blown by a blast furnace, controlling the coal ratio at 50-80 kg/thm, controlling the blowing amount of the converter slag at 40-80 kg/thm, wherein the mass percentages of FeO and MgO in the converter slag are respectively more than 10% and 6%; controlling the oxygen enrichment rate of blast furnace hot air to be more than 8%; the slag temperature is greater than 1600 ℃.

Description

Ultrahigh Al2O3Blast furnace smelting method of furnace slag

Technical Field

The invention belongs to the field of ferrous metallurgy, and particularly relates to ultrahigh Al₂O₃A blast furnace smelting method of furnace slag.

Background

Under the background that the steel industry is influenced by conditions such as excess productivity and the like, the market performance is low, so that the cost reduction becomes the first work for keeping the survival of various steel plants, and a trend that a blast furnace is matched with high-aluminum low-price ores in large quantity is formed. However, when blast furnaces use high-alumina ore in large quantities, this results in increased slag viscosity, difficulty in tapping and tapping the blast furnace, and increased fuel consumption. Therefore, in order to use a large amount of high-alumina ore and effectively reduce the production cost of the blast furnace, the high-alumina ore is basically matched with a large amount of low-alumina ore for use, and finally, Al in blast furnace slag is added₂O₃The content is controlled below 16%. However, this dilution "Al in slag₂O₃The use method of the high-alumina ore limits the use of the high-alumina ore in large quantity, and the production cost of the blast furnace is difficult to be greatly reduced.

In recent years, with the increasing importance of various steel plants on reducing the production cost of blast furnaces, new methods for using high-alumina ore in large proportion are continuously proposed:

CN201410557803.7 (a blast furnace slag system for blast furnace smelting) discloses a high-alumina slag system for blast furnace smelting. The invention innovatively utilizes Al on the premise of meeting the performance requirement of the blast furnace smelting slag system₂O₃By its own action in the slag system, with Al₂O₃Replace SiO in the existing slag system₂While reducing SiO₂The content of Al in the slag can be obtained by changing the traditional aluminosilicate slag system for high-alumina smelting into the aluminosilicate slag system, utilizing the current blast furnace to smelt high-alumina ore varieties and matching with other iron ores₂O₃The slag system reaches 20 to 30 percent or even higher, and the requirement of blast furnace smelting slag system is met. However, the slag system slag has poor stability, and the viscosity of the slag is greatly changed by component fluctuation and temperature fluctuation in the blast furnace, so that the stable and smooth operation of the blast furnace is influenced.

CN201110190772.2 (a method for improving the fluidity of high-alumina slag in the blast furnace ironmaking process) discloses a method for improving the fluidity of high-alumina slag in the blast furnace ironmaking process, which comprises the following steps: firstly, in the blast furnace ironmaking process, the boron-containing iron ore concentrate is used for partially replacing iron ore powder and accounts for the mass percentage8-27% of Fe content is more than or equal to 50%, and B content₂O₃The method comprises the following steps of preparing a mixture of boron-containing iron concentrate with the concentration of less than or equal to 10%, 8-15% of flux, 2.5-4.5% of fuel and 53-82% of iron ore powder, conveying the mixture to a sintering machine for sintering to obtain boron-containing sintered ore, smelting the boron-containing sintered ore by using a blast furnace, separating iron and boron of the boron-containing sintered ore, enabling boron oxide to enter blast furnace slag to improve the fluidity of the slag, and solving the problems of thick slag and poor molten iron desulphurization effect caused by smelting high-alumina slag by using the blast furnace.

The above patent has a disadvantage in that B in iron ore increases slag fluidity although the above patent can reduce slag viscosity₂O₃Can not enter the slag by 100 percent, and has a part B₂O₃The B is reduced into B and enters into slag, which can affect the production of subsequent special steel.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide the ultrahigh Al₂O₃Blast furnace smelting method of slag, which can lead Al in the slag₂O₃The mass percentage content is increased to 30-40%, the use proportion of low-price high-aluminum ores can be greatly increased, and the blast furnace iron-making cost is greatly reduced.

In order to realize the purpose of the invention, the technical scheme adopted by the invention is as follows:

ultrahigh Al₂O₃The blast furnace smelting method of the furnace slag is characterized by comprising the following steps: the slag contains 10-16% of MgO and Al according to mass percentage₂O₃30-40% of FeO and 1-2.5% of FeO; the binary basicity R2 of the slag is 0.8-0.9; controlling blast temperature of the blast furnace to be more than 1250 ℃; adding converter slag into pulverized coal blown by a blast furnace, controlling the coal ratio at 50-80 kg/thm, controlling the blowing amount of the converter slag at 40-80 kg/thm, wherein the mass percentages of FeO and MgO in the converter slag are respectively more than 10% and 6%; the oxygen enrichment rate of the blast furnace hot air is controlled to be more than 8 percent.

The slag temperature is greater than 1600 ℃.

The blast kinetic energy of the blast furnace is more than 140 KJ/s.

The mass percentage of the part of the converter slag with the granularity of less than 0.074mm is more than or equal to 78 percent.

The mass percentage of Al2O3 in the iron ore in the blast furnace smelting process is 7-15%.

The principle of the invention is as follows: the viscosity of the slag is mainly influenced by the composition and temperature of the slag, when Al in the slag₂O₃When the content is increased, the slag viscosity increases and the fluidity deteriorates. Therefore, in the blast furnace smelting of high-alumina ore, Al in the slag is generally controlled₂O₃The content is less than 15 percent, so that the stable and smooth operation of the blast furnace is ensured, and the charging proportion of the high-alumina ore is limited. When the blast furnace slag content is increased to 30%, it is necessary to adjust not only the slag composition but also the slag temperature to ensure the viscosity and fluidity of the slag. The invention reduces the binary alkalinity, and reduces the CaO in the blast furnace slag which is easy to react with SiO₂Generates a high melting point substance of wollastonite (2 CaO. SiO)₂Melting point 2150 ℃ C.). Meanwhile, converter slag is blown into the slag, so that the FeO content in the slag is ensured, and the slag plays a role of a fluxing agent; and the coal injection amount is reduced, the coal powder is ensured to be completely combusted, the coal powder which is not combusted is prevented from entering the slag, and the fluidity of the slag is reduced. In addition, the theoretical combustion temperature is increased by increasing the air temperature and the oxygen enrichment rate, so that the temperature of the slag in the hearth is increased, the fluidity of the slag can be obviously improved, and the viscosity of the slag is reduced.

Compared with the prior art, the invention has the beneficial effects that: 1. the invention can greatly increase the usage amount of low-price high-alumina ore and reduce the cost of blast furnace charging raw materials, thereby reducing the blast furnace ironmaking cost; 2. the invention does not need to add flux such as fluorite, manganese ore and the like into the blast furnace burden; 3. can recycle the steelmaking converter slag, and is beneficial to energy conservation and emission reduction of steel plants.

Detailed Description

The following description is given with reference to specific examples:

high Al in examples₂O₃The iron ore is low-value lump ore from Australia, and Al in the ore₂O₃The content is 7-15%. The furnace charge material parameters, blast furnace control parameters and molten iron ingredients are shown in tables 1, 2 and 3. No. 1 is a control parameter for smelting common high-alumina slag, and No. 2, No. 3 and No. 4 are the method adopting the inventionThe method controls the blast furnace slag components and blast furnace parameters, and after the method is adopted to smelt the high-aluminum ore, the smelting proportion of the low-price high-aluminum ore is obviously improved, the molten iron cost is obviously improved, and simultaneously the components and the yield of the molten iron are basically kept unchanged.

TABLE 1 composition of charged raw materials

TABLE 2 blast furnace control parameters

TABLE 3 blast furnace ironmaking water composition, wt%

Numbering	C	Si	S	P
					1	5.2	0.4	0.03	0.07
2	4.9	0.4	0.04	0.08
					3	4.8	0.5	0.03	0.08
4	5.2	0.6	0.04	0.09

Claims

1. Ultrahigh Al₂O₃The blast furnace smelting method of the furnace slag is characterized by comprising the following steps: the slag contains 10-16% of MgO and Al according to mass percentage₂O₃30-40% of FeO and 1-2.5% of FeO; the binary basicity R2 of the slag is 0.8-0.9; controlling blast temperature of the blast furnace to be more than 1250 ℃; adding converter slag into pulverized coal blown by a blast furnace, controlling the coal ratio at 50-80 kg/thm, controlling the blowing amount of the converter slag at 40-80 kg/thm, wherein the mass percentages of FeO and MgO in the converter slag are respectively more than 10% and 6%; the oxygen enrichment rate of the blast furnace hot air is controlled to be more than 8 percent.

2. Ultra-high Al according to claim 1₂O₃The blast furnace smelting method of the furnace slag is characterized by comprising the following steps: the slag temperature is greater than 1600 ℃.

3. Ultra-high Al according to claim 1₂O₃The blast furnace smelting method of the furnace slag is characterized by comprising the following steps: the mass percentage of the part of the converter slag with the granularity of less than 0.074mm is more than or equal to 78 percent.

4. Ultra-high Al according to claim 1₂O₃A blast furnace smelting method of furnace slag is characterized in that: the blast kinetic energy of the blast furnace is more than 140 KJ/s.

5. Ultra-high Al according to claim 1₂O₃The blast furnace smelting method of the furnace slag is characterized by comprising the following steps: al of the iron ore in the blast furnace smelting process₂O₃The mass percentage content is 7-15%.