A method for reducing the melting point of high-titanium blast furnace slag

Abstract

The present invention relates to the technical field of blast furnace ironmaking, and in particular to a method for reducing the melting point of high-titanium blast furnace slag. The method comprises the following steps: uniformly stirring bentonite and talcum powder to obtain an additive; uniformly sandblasting the additive prepared in step one on the surface of the slag ditch before slag discharge; during the slag discharge process, spraying the additive prepared in step one on the surface of the flowing high-titanium blast furnace slag, spraying in all directions, and obtaining high-titanium blast furnace slag with a reduced melting point. The present invention effectively increases the silicon content by spraying the additive into the slag ditch and on the surface of the high-titanium blast furnace slag, reduces the melting point of the high-titanium blast furnace slag in the slag ditch, enhances its fluidity, shortens the residence time of the high-titanium blast furnace slag from the blast furnace through the slag ditch to the slag pot, reduces the temperature loss during the flow process, and makes the initial temperature of the slag pot for high-temperature carbonization reaction increase by 100-200°C, thereby realizing energy saving in the reaction process.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace ironmaking, in particular to a method for reducing the melting point of high-titanium blast furnace slag. Background Art

[0002] Blast furnace ironmaking is the process of reducing iron ore or iron oxide to obtain liquid pig iron and blast furnace slag. The blast furnace slag formed flows into the slag pot through different grooves. Panxi area contains a large amount of vanadium-titanium magnetite. The blast furnace slag formed after smelting in the blast furnace has a high titanium content and is a high-titanium blast furnace slag. The main difference between high-titanium blast furnace slag and ordinary blast furnace slag is that the SiO2 content of high-titanium blast furnace slag is 10-12% lower than that of ordinary blast furnace slag, and the TiO2 content is 12-15% higher than that of ordinary blast furnace slag. Due to the high TiO2 content, high-titanium blast furnace slag is partially reduced to high-melting-point TiC (melting point 3150℃) and TiN (melting point 2950℃) in the reducing atmosphere of the blast furnace, which is dispersed and suspended in the slag as solid particles, resulting in a high melting point of the blast furnace slag.

[0003] The high titanium blast furnace slag has a high TiO2 content. In order to better recover titanium resources, the high titanium blast furnace slag needs to be subjected to a high temperature carbonization reaction. Due to the high melting point and poor fluidity of the blast furnace slag, the temperature drops rapidly during the process of flowing from the blast furnace through the slag ditch to the slag pot, resulting in the initial temperature of the high titanium blast furnace slag for high temperature carbonization reaction being reduced to 1100-1200°C. The temperature needs to be raised to meet the high temperature carbonization reaction, resulting in serious energy waste. In addition, the blast furnace slag contains titanium dispersed in solid particles, resulting in the inlay distribution of titanium with iron and iron oxides, and the particle particles are only about 5μm, which is not conducive to the collection of titanium-containing mineral phases. Summary of the invention

[0004] The object of the present invention is to provide a method for lowering the melting point of high-titanium blast furnace slag, which can lower the melting point of high-titanium blast furnace slag, ensure its flow rate in the process of flowing from the blast furnace through the blast furnace slag outlet groove to the slag pot, and reduce the heat loss of high-titanium blast furnace slag during the flow process.

[0005] The present invention provides a method for reducing the melting point of high-titanium blast furnace slag, comprising the following steps:

[0006] Step 1: Mix bentonite and talcum powder evenly to obtain an additive;

[0007] Step 2: Before slag discharge, the additive prepared in step 1 is evenly sandblasted on the surface of the slag discharge groove;

[0008] Step 3: During the slag tapping process, the additive prepared in step 1 is sprayed on the surface of the flowing high-titanium blast furnace slag, and the spraying is performed in all directions to obtain high-titanium blast furnace slag with a reduced melting point.

[0009] Preferably, the specific steps of step one are: setting a stirring device within 20 meters from the blast furnace slag ditch, stirring the bentonite and talcum powder evenly according to proportion, and continuously stirring to obtain the additive.

[0010] Preferably, in step 1, the weight ratio of bentonite to talc is (1-9): (9-1).

[0011] Preferably, in step 1, the particle sizes of bentonite and talc are both less than 200 mesh.

[0012] Preferably, in step 1, the moisture content of bentonite and talc is less than 2%.

[0013] Preferably, the components of the bentonite in step 1 include, by weight: 2-3 parts of CaO, 4-5 parts of MgO, 16-18 parts of Al2O3, 50-53 parts of SiO2, and 1-2 parts of Fe2O3.

[0014] Preferably, the components of the talc in step 1 include, by weight: 31-32 parts of MgO and 62-65 parts of SiO2.

[0015] Preferably, the specific steps in step 2 are: 5-10 minutes before slag discharge, spray the additive prepared in step 1 evenly on the surface of the slag discharge groove using a high temperature resistant spray gun.

[0016] Preferably, the spraying thickness in step 2 is 5-10 mm.

[0017] Preferably, in step three, the speed of spraying the additive prepared in step one is 1-5 L / s.

[0018] Beneficial effects:

[0019] The present invention can effectively increase the silicon content of the slag by spraying additives into the slag discharge groove and the surface of the high-titanium blast furnace slag, reduce the melting point of the high-titanium blast furnace slag in the slag discharge groove, enhance its fluidity, shorten the residence time of the high-titanium blast furnace slag in the process of flowing from the blast furnace through the slag groove to the slag pot, reduce the temperature loss in the flow process, increase the initial temperature of the high-temperature carbonization reaction when it reaches the slag pot by 100-200°C, reduce the melting point of the high-temperature carbonization reaction, improve the high-temperature carbonization reduction rate, and achieve energy saving in the reaction process. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like, which indicate directions or positional relationships, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0022] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] Example 1

[0024] A method for lowering the melting point of high-titanium blast furnace slag comprises the following steps:

[0025] Step 1: Set up a stirring device within 20 meters of the blast furnace slag ditch, stir the bentonite and talcum powder evenly according to the proportion, and continue stirring to obtain the additive; continuous stirring can effectively prevent the additive from agglomerating and keep it in a relatively stable state;

[0026] The weight ratio of bentonite to talc is (1-9): (9-1), and the particle size of bentonite and talc is less than 200 mesh, which is convenient for mixing high-titanium blast furnace slag evenly. The moisture content of bentonite and talc is less than 2%. Controlling the moisture content can effectively prevent the additive from contacting with high-temperature high-titanium blast furnace slag and causing explosion. In step 1, the components of bentonite include by weight: 2-3 parts of CaO, 4-5 parts of MgO, 16-8 parts of Al2O3, 50-53 parts of SiO2, and 1-2 parts of Fe2O3; the components of talc include by weight: 31-32 parts of MgO and 62-65 parts of SiO2. Preferably, the components of bentonite include, by weight: 2.26 parts of CaO, 4.65 parts of MgO, 16.54 parts of Al2O3, 50.95 parts of SiO2, and 1.36 parts of Fe2O3; the components of talc include, by weight: 31.7 parts of MgO and 63.5 parts of SiO2.

[0027] Compared with talc, bentonite has a relatively low SiO2 content, but it contains a higher Al2O3. With the addition of bentonite, the Al2O3 can reduce the basicity of high-titanium blast furnace slag and further enhance the fluidity of high-titanium blast furnace slag.

[0028] Step 2: 5-10 minutes before slag discharge, use a high temperature resistant spray gun to evenly spray the additive prepared in step 1 on the surface of the slag discharge groove; the spraying thickness is 5-10mm.

[0029] High-titanium blast furnace slag has a large proportion of high-melting-point compounds, and the temperature of the blast furnace slag is generally controlled at 1700-1800℃. However, due to the low temperature of the blast furnace slag ditch, the temperature of the contact part of the blast furnace slag drops rapidly when it contacts the bottom and wall of the slag ditch, as well as the air. A small amount of blast furnace slag will directly stick to the slag ditch, resulting in a significant drop in temperature. Bentonite and talcum powder have a high SiO2 content. By spraying them into the slag ditch, the melting point of the blast furnace slag in the contact area can be lowered, and the fluidity can be enhanced. The bentonite and talcum powder are taken away during the flow process, but the temperature of the slag ditch has been increased, so the flow rate increases significantly, reducing the residence time of the blast furnace slag in the slag ditch and reducing the temperature drop loss during the flow to the slag pot.

[0030] Step three: During the slag tapping process, the additive prepared in step one is sprayed on the surface of the flowing high-titanium blast furnace slag. The speed of spraying the additive prepared in step one is 1-5L / s, and the spraying is performed in all directions to obtain high-titanium blast furnace slag with a lowered melting point, thereby improving the fluidity of the high-titanium blast furnace slag in the slag tapping ditch.

[0031] By spraying additives into the slag ditch and on the surface of high-titanium blast furnace slag, the silicon content can be effectively increased, the melting point of high-titanium blast furnace slag in the slag ditch is lowered, its fluidity is enhanced, and the residence time of high-titanium blast furnace slag in the process of flowing from the blast furnace through the slag ditch to the slag pot is shortened. It is ensured that after the blast furnace completes slag discharge, the high-titanium blast furnace slag flows quickly to the slag pot, reducing the temperature loss during the flow process, and the initial temperature of the slag pot for high-temperature carbonization reaction is increased by 100-200°C, which also reduces the melting point of the high-temperature carbonization reaction, improves the high-temperature carbonization reduction rate, and realizes energy saving in the reaction process. It can ensure that the additives are mixed with the high-titanium blast furnace slag and flow quickly into the slag pot. The impact when reaching the slag pot makes them evenly mixed with each other. Since the particle size of bentonite and talcum powder is controlled below 200 mesh, they react quickly with the high-titanium blast furnace slag during the mixing process. The SiO2 therein increases the grain size of the titanium-containing mineral phase in the high-titanium blast furnace slag to 20-30μm, which is convenient for better collection of the titanium-containing mineral phase in the later high-temperature carbonization reduction process.

[0032] When adding additives in different proportions and using different spraying thicknesses and spraying times, the grain sizes of the titanium-containing mineral phase in the final high-titanium blast furnace slag are shown in Table 1. The components of bentonite include by weight: 2.26 parts of CaO, 4.65 parts of MgO, 16.54 parts of Al2O3, 50.95 parts of SiO2, and 1.36 parts of Fe2O3; the components of talc include by weight: 31.7 parts of MgO and 63.5 parts of SiO2.

[0033] Table 1

[0034]

[0035] As shown in Table 1, when the thickness of the additive sprayed in the slag discharge groove is 10 mm and the mass ratio of bentonite to talc is 1:9, the final high-titanium blast furnace slag has the largest grain size of titanium-containing mineral phase, which is 28.1 μm, which is convenient for better collection of titanium-containing mineral phase in the later high-temperature carbonization reduction process. The slag discharge temperature of blast furnace slag has little effect on the subsequent titanium-containing mineral phase grain size.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for lowering the melting point of high-titanium blast furnace slag, characterized in that: The following steps are involved: Step 1: Set up a stirring device within 20 meters of the blast furnace slag ditch, stir the bentonite and talcum powder evenly according to the proportion, and continue stirring to obtain the additive; The weight ratio of bentonite to talc is (1-9): (9-1), the components of bentonite include 2-3 parts of CaO, 4-5 parts of MgO, 16-18 parts of Al2O3, 50-53 parts of SiO2, and 1-2 parts of Fe2O3, and the components of talc include 31-32 parts of MgO and 62-65 parts of SiO2 by weight; the moisture content of bentonite and talc is less than 2%; Step 2: Before slag discharge, the additive prepared in step 1 is evenly sandblasted on the surface of the slag discharge groove; Step 3: During the slag tapping process, the additive prepared in step 1 is sprayed on the surface of the flowing high-titanium blast furnace slag, and the spraying is performed in all directions to obtain high-titanium blast furnace slag with a reduced melting point.

2. The method according to claim 1, characterized in that In step 1, the particle sizes of bentonite and talc are both less than 200 meshes.

3. The method according to claim 1, characterized in that The specific steps in step 2 are: 5-10 minutes before slag discharge, use a high temperature resistant spray gun to evenly spray the additive prepared in step 1 on the surface of the slag discharge groove.

4. The method according to claim 3, characterized in that The spraying thickness in step 2 is 5-10 mm.

5. The method according to claim 1, characterized in that In step 3, the speed of spraying the additive prepared in step 1 is 1-5 L / s.

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