Metal mixer lining protection method

Abstract

The invention discloses a furnace lining protection method of a metal mixer, which is used for protecting the furnace lining of the metal mixer by directionally distributing high-titanium molten iron with titanium content greater than or equal to 0.08% from a blast furnace into the metal mixer, and specifically comprises the following processes: in a slag adhering stage, controlling the furnace temperature of the metal mixer to be 1300-1330 DEG C; and in the molten iron injection stage, molten iron is continuously injected into the metal mixer until the molten iron reaches the operation liquid level line of the metal mixer, the furnace temperature of the metal mixer is controlled to be 1330-1350 DEG C, and heat preservation is conducted for 30 min or above. According to the method, the titanium element in the molten iron reacts with the material of the furnace lining, so that the problem that the furnace lining of the metal mixer is seriously eroded is effectively solved, the operation stability of the metal mixer is remarkably improved, production interruption and potential safety hazards caused by the problem of the furnace lining are reduced, and the service life of the metal mixer is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel smelting, in particular to a mixed iron furnace lining protection method. BACKGROUND

[0002] The mixed iron furnace is an important thermal equipment in the steel smelting industry, mainly used for storing, heat preserving, mixing and homogenizing the molten iron from the blast furnace, and is located between the blast furnace and the steelmaking furnace, playing a key role in buffering and coordinating. The blast furnace tapping is carried out every few hours, while the converter steelmaking is carried out in batches. The mixed iron furnace is used as a huge storage tank to accept and store the molten iron from multiple blast furnaces, ensuring continuous and stable supply of molten iron for the converter, and solving the problem of mismatch between the production rhythm of the blast furnace and the converter, making the whole production process more smooth.

[0003] The mixed iron furnace is composed of a furnace body, a tilting mechanism, a heating system and a molten iron outlet, wherein the furnace body includes a furnace shell and a furnace lining located inside the furnace shell. Generally, the temperature of the molten iron flowing out of the blast furnace is between 1350-1500℃, even if it is cooled during transportation, it still has a high temperature after entering the mixed iron furnace. The furnace lining needs to be directly in contact with the high-temperature molten iron. As the use time increases, the furnace lining will be eroded by the molten iron, which not only shortens the service life of the mixed iron furnace and increases the maintenance cost, but also may cause safety accidents. Therefore, in the prior art, new type of alkaline refractory material high alumina brick and mullite brick are usually used as furnace lining material, or the furnace lining is protected by regularly gunning refractory material on the eroded surface of the furnace lining to reduce the consequences of molten iron erosion.

[0004] However, although the new type of alkaline refractory material improves the erosion resistance to some extent, its erosion resistance gradually decreases with the increase of use time and changes in smelting conditions, and it is difficult to effectively resist the chemical erosion of high-temperature molten iron and the mechanical scouring caused by slag for a long time, resulting in limited service life of the furnace lining. In addition, regular gunning of refractory material on the eroded surface of the furnace lining not only increases labor input, but also suspends production during the gunning process, affecting production continuity. SUMMARY

[0005] Therefore, it is necessary to provide a mixed iron furnace lining protection method to effectively solve the problem of mixed iron furnace lining erosion and prolong the service life of the mixed iron furnace.

[0006] The present application provides a mixed iron furnace lining protection method, which protects the furnace lining of the mixed iron furnace by directing the high-titanium molten iron with titanium content greater than or equal to 0.08% from the blast furnace into the mixed iron furnace, specifically including the following processes: During the slag hanging stage, the furnace temperature of the mixed iron furnace is controlled to be 1300-1330℃; In the hot metal injection stage, high-titanium hot metal is continuously injected into the mixing furnace until the high-titanium hot metal reaches the operating liquid level line of the mixing furnace, the temperature of the mixing furnace is controlled to be 1330-1350 DEG C, and the temperature is kept for more than 30 minutes. In one of the embodiments, in the mixing furnace slagging stage, the temperature of the mixing furnace is controlled to be 1280-1300 DEG C.

[0007] In one of the embodiments, the high-titanium hot metal with a titanium content of 0.08% or more comes from different blast furnaces.

[0008] In one of the embodiments, the temperature control of the mixing furnace is realized by a temperature control module and a heating module, and the temperature control system comprises thermocouple temperature sensors and a control module arranged uniformly at different heights and positions inside the mixing furnace. The thermocouple temperature sensors are embedded and fixed inside the furnace lining and are electrically connected to the control module. The heating module is a gas heating system, which is electrically connected to the control module.

[0009] In one of the embodiments, the control module controls the gas flow of the gas heating system according to the detection temperature of the thermocouple temperature sensor.

[0010] The beneficial effects of the present application are: (1) The mixing furnace lining protection method of the present application realizes full contact between the high-titanium hot metal and the composition materials of the mixing furnace lining, i.e. high-alumina bricks and mullite bricks. The high-alumina bricks are mainly composed of Al2O3, and the mullite bricks are composed of 3Al2O3·2SiO2. At a set temperature, titanium in the hot metal is oxidized to TiO2, TiO2 reacts with Al2O3 to generate aluminum titanate Al2O3·TiO2, forming a glassy protective layer, and the hot metal erodes the lining. In addition, TiO2 is dissolved into the mullite lattice to form a solid solution (Al,Ti)2O3·SiO2, which strengthens the grain boundary, inhibits the decomposition of mullite at high temperature, and improves the corrosion resistance of mullite bricks. By automatically generating a protective layer and a solid solution, the corrosion resistance of the furnace lining can be improved, and the service life of the mixing furnace can be prolonged. (2) In the slagging stage, the temperature of the mixing furnace is controlled to be 1300-1330 DEG C, and the viscosity of the slag formed at this temperature is less than or equal to 2.0 Pa·s, which can realize uniform coverage and improve the protection degree of the slag on the furnace lining. (3) In the mixing furnace slagging stage, the temperature of the mixing furnace is controlled to be 1280-1300 DEG C, which can reduce the flowability of the slag and prevent the protective layer or solid solution from being taken away during slagging. DETAILED DESCRIPTION

[0011] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail.

[0012] In the blast furnace smelting process, molten iron produced by multiple different blast furnaces is usually input into a mixing furnace for storage, etc. Different raw materials are used in the smelting process, and the titanium content in the molten iron produced by the blast furnace is also different.

[0013] In an embodiment, the mixing furnace lining protection method of the present embodiment protects the lining of the mixing furnace by directing high-titanium molten iron with a titanium content greater than or equal to 0.08% from the blast furnace into the mixing furnace, and specifically includes the following processes: In the slag hanging stage, the furnace temperature of the mixing furnace is controlled to be 1300℃-1330℃, at which temperature the viscosity of the lining protection slag is ≤2.0 Pa·s, which can achieve uniform coverage of the lining.

[0014] In the molten iron injection stage, high-titanium molten iron is continuously injected into the mixing furnace until the high-titanium molten iron reaches the operating liquid level line of the mixing furnace, the furnace temperature of the mixing furnace is controlled to be 1330℃-1350℃, and the temperature is maintained for more than 30 minutes.

[0015] The lining is composed of high-alumina bricks and mullite bricks, the high-alumina bricks are mainly composed of Al2O3, and the mullite bricks are composed of 3Al2O3·2SiO2.

[0016] The titanium in the high-titanium molten iron is oxidized to TiO2, which reacts with Al2O3 to form aluminum titanate Al2O3·TiO2, forming a glassy protective layer that erodes the lining. In addition, TiO2 is solid-solved into the mullite lattice to form a solid solution (Al,Ti)2O3·SiO2, which strengthens the grain boundary, inhibits the decomposition of mullite at high temperatures, and improves the corrosion resistance of mullite bricks. By actively generating a protective layer and a solid solution, the corrosion resistance of the lining can be improved, and the service life of the mixing furnace can be extended.

[0017] At a temperature of 1330℃-1350℃, the rate of titanium oxidation to TiO2 is greater than 80%, and this temperature can promote the formation of aluminum titanate Al2O3·TiO2. Maintaining the temperature for more than 30 minutes allows TiO2 to fully react with Al2O3, and provides sufficient time for TiO2 to be solid-solved into the mullite lattice.

[0018] Specifically, the high-titanium molten iron with a titanium content greater than or equal to 0.08% comes from different blast furnaces. The titanium content in the molten iron can be detected by a spectrometer, and in the present embodiment, the high-titanium molten iron with a titanium content greater than or equal to 0.08% is diverted to the mixing furnace by detecting the titanium content in the molten iron of different blast furnaces. When the molten iron content of all blast furnaces in the same ironmaking area is less than 0.08%, titanium-containing iron ore or pure titanium can be added to one or more blast furnaces to increase the titanium content in the molten iron.

[0019] In one of the embodiments, the temperature of the mixing furnace is controlled to be 1280-1300 DEG C during the slagging stage of the mixing furnace, which can reduce the slag fluidity and prevent the protective layer or solid solution from being taken away during the slagging.

[0020] In one of the embodiments, the temperature control of the mixing furnace is realized by a temperature control module and a heating module, and the temperature control system comprises thermocouple temperature sensors and a control module arranged uniformly at different heights and positions inside the mixing furnace.

[0021] The thermocouple temperature sensors used in the embodiment have a measurement range of 1200-1600 DEG C.

[0022] The thermocouple temperature sensors are embedded and fixed in the interior of the furnace lining and are electrically connected to the control module; the heating module is a gas heating system, which is electrically connected to the control module. The sensors can convert the temperature signals into electrical signals and transmit them to the control module.

[0023] In one of the embodiments, the control module controls the gas flow of the gas heating system according to the detected temperature of the thermocouple temperature sensors. Specifically, when the temperature is lower than the lower limit of the preset temperature, the control module increases the gas flow of the gas burner to increase the temperature; when the temperature is higher than the upper limit of the preset temperature, the control module reduces the gas flow of the gas burner to reduce the temperature.

[0024] The mixing furnace lining protection method of the application utilizes the reaction between the titanium element in the molten iron and the material of the furnace lining to effectively solve the problem of serious erosion of the mixing furnace lining. The stability of the mixing furnace operation is significantly improved, the production interruption and safety hazards caused by the furnace lining problem are reduced, the service life of the mixing furnace is prolonged, the frequency of refractory replacement and gunning maintenance is reduced, and thus the production cost is reduced. At the same time, the application makes full use of the composition characteristics of the molten iron to realize the optimal utilization of resources, and has good economic and environmental benefits.

[0025] The above embodiments only express several embodiments of the application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent of the application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the application, several modifications and improvements can be made, which belong to the protection scope of the application. Therefore, the protection scope of the application should be subject to the appended claims.

Claims

1. A method for protecting the lining of a blast furnace, characterized in that, The furnace lining of the blast furnace is protected by directional diversion of high-titanium molten iron (with a titanium content of ≥0.08%) from the blast furnace into the blast furnace. This process specifically includes the following steps: During the slag-coating stage, the furnace temperature of the blast furnace is controlled at 1300℃~1330℃; During the molten iron injection stage, high-titanium molten iron is continuously injected into the mixing furnace until it reaches the operating liquid level line of the mixing furnace. The furnace temperature is controlled at 1330℃~1350℃ and held for more than 30 minutes.

2. The method for protecting the lining of a blast furnace according to claim 1, characterized in that, During the slag removal stage of the blast furnace, the furnace temperature is controlled at 1280℃~1300℃.

3. The method for protecting the lining of a blast furnace according to claim 2, characterized in that, The high-titanium molten iron with a titanium content of ≥0.08% comes from different blast furnaces.

4. The method for protecting the lining of a blast furnace according to claim 3, characterized in that, The furnace temperature of the blast furnace is controlled by a temperature control module and a heating module. The temperature control system includes thermocouple temperature sensors and a control module that are uniformly arranged at different heights and positions inside the blast furnace. The thermocouple temperature sensor is embedded and fixed inside the furnace lining and is electrically connected to the control module. The heating module is a gas heating system, and the gas heating system is electrically connected to the control module.

5. The method for protecting the lining of a blast furnace according to claim 4, characterized in that, The control module controls the gas flow rate of the gas heating system based on the temperature detected by the thermocouple temperature sensor.