A refractory coated ladle dam head and method of making same

Abstract

The application discloses a converter stopper plug head coated with a refractory heat-insulating layer and a preparation method thereof, which comprises a converter stopper plug head body and a 3-5mm-thick refractory heat-insulating layer coated on the outer layer of the body; the converter stopper plug head body is prepared by combining, compounding, stirring and machine-pressing various refractory raw materials, and a stopper plug body without adding a counterweight iron core is prepared; a magnesium refractory heat-insulating layer with high strength and good refractory performance is coated on the outer layer of the body; the finished converter stopper plug head coated with the refractory heat-insulating layer has a volume density and use effect reaching or exceeding that of the stopper plug head with the counterweight iron core; the application saves raw material cost and production cost, improves economic benefits, reduces forming difficulty, improves forming efficiency and improves the effect of stopping slag in a converter.

Description

Technical Field

[0001] This invention relates to the field of refractory materials technology for steelmaking converters, and more specifically to a slag-blocking plug head for a converter coated with a refractory insulation layer and its preparation method. Background Technology

[0002] Currently, after the molten steel is smelted in the converter, it is poured into a ladle through the tapping spout. Towards the end of the tapping process, when most of the molten steel has been discharged from the converter, a strong vortex forms at the tapping spout, inevitably causing slag to flow out with the steel. Because the chemical composition of the slag is complex, especially the sulfur and phosphorus elements it contains, it has a significant impact on the quality of steel products. Therefore, it is crucial to strictly control the amount of slag flowing into the ladle with the molten steel to reduce slag contamination, effectively improve the purity of the molten steel, and reduce sulfur and phosphorus reversion. Currently, there are many commonly used slag-blocking methods in converters, including pneumatic slag blocking, electromagnetic slag blocking, slag-blocking ball methods, slag-blocking plug methods, slag-blocking cap methods, and sliding plate slag blocking methods. Each method is suitable for different production processes and steel grades. The appropriate slag-blocking method should be selected based on the actual conditions of the converter. The most commonly used slag-blocking method in domestic steel plants is still the slag-blocking plug method. Compared to other methods, the slag-blocking plug technology is simple, easy to operate, and economical in its slag-blocking effect, and it is still widely used in converter slag blocking in many steel plants.

[0003] Slag-blocking plugs are widely used in converters, and there are many types of slag-blocking plugs, but their main components are basically the same: the plug head and the guide rod. During use, the guide rod is inserted into the tap hole to guide and position the plug. The density of the plug head varies depending on the steel grade being smelted by different steel mills, generally ranging from 3.0 to 4.5 g / cm³, between that of molten steel and slag. The plug head is typically a gyro-shaped conical structure (with 3-4 flow channels on the cone), including an internal core material and a refractory material surrounding it. The guide rod consists of a core material of threaded steel and a refractory material surrounding it. For example, patent number CN 105400923A discloses an integrally molded converter slag-blocking plug and its castable material, which includes a slag-blocking plug body (plug head) and a guide rod. The slag-blocking plug body has a steel flow channel on its side. The slag-blocking plug includes a core material and a refractory layer cast around the core material. The characteristic is that the slag-blocking plug is integrally cast by fixing the core material at the center position of the mold and then casting the slag-blocking plug body and the guide rod in one go. CN 202492539 U discloses a slag-blocking plug for converter tapping, which includes a slag-blocking plug head and a guide rod. The guide rod includes a guide rod core material and a guide rod refractory layer. The slag-blocking plug head is composed of a counterweight iron core and a refractory material layer. The counterweight iron core is a frustum-shaped cone with a through hole on its center line. The refractory material layer covers the outside of the counterweight iron core.

[0004] The following technical problems exist in the production of slag-blocking plug heads in the existing technology:

[0005] (1) The slag plug cone is composed of a counterweight core material and a refractory material layer. The counterweight core material is generally an iron core material processed into the required shape. Its price is expensive. In addition, the processing fee increases its economic cost, making the slag plug, which is already not expensive, almost unprofitable.

[0006] (2) It is difficult to press-form the slag-blocking plug head with added counterweight iron core. The counterweight iron core is easy to deviate from the center line, and the molding pressure is not easily transmitted to the lower part of the counterweight iron core, resulting in insufficient density of the molded product and inconsistency between the top and bottom. Similarly, the slag-blocking plug head with added counterweight iron core also has the problems of difficulty in fixing the iron core and easy deviation from the center line during casting molding.

[0007] (3) The slag-blocking plug has poor fire resistance, weak erosion resistance, low scouring resistance, and low fire resistance.

[0008] Therefore, how to provide a converter slag plug head with a coated refractory insulation layer that has high overall density, good refractory performance, erosion resistance, corrosion resistance, and excellent slag blocking effect after being assembled with a guide rod is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0009] In view of this, the present invention provides a converter slag-blocking plug head coated with a refractory insulation layer and its preparation method, which can save raw materials and production costs of converter slag-blocking plugs, improve the molding efficiency of the converter slag-blocking plug head body, reduce molding difficulty, improve the refractory performance of the converter slag-blocking plug head coated with a refractory insulation layer, increase the bulk density, and improve the slag-blocking effect of the converter slag-blocking plug.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A converter slag-blocking plug head coated with a refractory insulation layer includes: a converter slag-blocking plug head body and a refractory insulation layer, wherein the refractory insulation layer is coated on the outer surface of the converter slag-blocking plug head body, and the raw materials of the converter slag-blocking plug head body include, by weight percentage: 25-45% 3-6mm iron ore, 20-40% 1-3mm iron ore, 10-20% 0-1mm 97.5 fused magnesia, 10-30% 200-mesh 97.5 fused magnesia powder, 0-5% activated alumina micro powder, 0-5% 96-silica ultrafine powder, and 2-5% liquid binder phenolic resin;

[0012] The raw materials of the refractory insulation layer coated on the plug body, by weight percentage, include: 20-40% 0-0.5mm 95 medium-grade magnesia, 50-70% 325-mesh lightly calcined active magnesium powder, 3-10% 325-mesh Guangxi white clay, and 3-8% pure calcium aluminate 71 cement.

[0013] The beneficial effect of the above technical solution lies in the fact that this invention, combined with the material requirements of the converter slag-blocking plug head for the use of refractory materials, makes practical and innovative choices in the use of raw materials and production processes. Specifically, the main raw material of the refractory material of the converter slag-blocking plug head body coated with a refractory insulation layer is 3-6mm iron ore, with 1-3mm iron ore as the main aggregate, ferric oxide ≥69%, and a particle density ≥4.6g / cm³. 3 Its main raw material, 3-6mm and 1-3mm iron ore, has low impurity content and high bulk density. The converter slag-blocking plug head produced by using this 3-6mm and 1-3mm iron ore as aggregate in combination with other refractory materials can replace the added counterweight iron core, meet the density requirements of the slag-blocking plug at the end of the molten steel tapping process in steel plants, and achieve the purpose of effective slag blocking and clean steel production in steel plants.

[0014] Preferably, the raw material of the converter slag-blocking plug head body contains,

[0015] The iron ore contains ≥69% Fe2O3 and has a particle density ρ ≥4.6 g / cm³. 3 ;

[0016] The 97.5 fused magnesia contains ≥97.5% MgO.

[0017] The active alumina micro powder contains ≥98% Al2O3 and has a median diameter (D50) ≤2.5μm.

[0018] The 96-silica ultrafine powder contains ≥96% SiO2 and has a median diameter (D50) ≤0.5μm.

[0019] The beneficial effect of the above technical solution is that this application ensures the quality of the slag-blocking plug head body by requiring and controlling the performance of raw materials.

[0020] Preferably, the refractory insulation layer material coated on the plug body contains,

[0021] The MgO content in the 95-grade magnesia is ≥95%;

[0022] The MgO content in the lightly calcined active magnesium powder is ≥91%;

[0023] The Al2O3 content in the Guangxi white clay is ≥30%;

[0024] The pure calcium aluminate 71 cement contains ≥71% Al2O3.

[0025] The beneficial effect of the above technical solution is that, in combination with the material requirements of converter slag baffles for refractory materials, the present invention selects raw materials with excellent refractory performance and good coating performance for the refractory insulation layer coated on the body of the baffle head. Specifically, the refractory insulation layer coated on the body of the baffle head uses 95 medium-grade magnesia with excellent refractory performance and economic practicality, and light-burned active magnesia with fast hardening speed and high hardening strength as the main raw materials. Clay and cement are added to increase its strength and plasticity, and saturated liquid brine is used as a binder, giving the refractory insulation layer material coated on the body of the baffle head high strength, erosion resistance, and ease of coating.

[0026] Preferably, the chemical composition of the converter slag-blocking plug body, by weight percentage, is Fe2O3≥45%, MgO≥32%, and the density of the plug body is 3.4-4.2 g / cm³. 3 .

[0027] Preferably, the refractory insulation layer coated on the plug body has a chemical composition of MgO ≥ 82% by weight percentage.

[0028] A method for preparing a converter slag-blocking plug head coated with a refractory insulation layer includes the following steps:

[0029] (1) Weigh each raw material according to the weight ratio of the raw material of the plug body, stir and mix, and add the raw material in the following order: first add the raw material with a particle size ≥0.088mm, then add the raw material with a particle size ≤0.088mm, dry mix for 3-8 minutes, add the liquid binder phenolic resin and mix at high speed for 20-25 minutes to obtain the mixture.

[0030] (2) Press the mixture from step (1) into shape using a friction brick press with a capacity of ≥1000 tons;

[0031] (3) After being pressed and molded, the plug body is obtained through drying, sorting and assembly processes;

[0032] (4) According to the weight required for coating the plug body with refractory insulation layer as described in step (3), weigh the refractory insulation layer raw material according to the weight ratio, stir and mix. The amount of mixing at one time should be used up within 30 minutes. After dry mixing for 3-8 minutes, add liquid binder brine and wet mix for 5-10 minutes to obtain refractory insulation layer slurry.

[0033] (5) Apply the refractory insulation slurry from step (4) evenly to the slag-blocking plug head body, with a coating thickness of 3-5mm.

[0034] (6) The coated slag-blocking plug head is dried and sorted to obtain the finished product.

[0035] The beneficial effects of the above technical solution are as follows: the order of adding raw materials in this application ensures uniform mixing of raw material particle size, avoiding uneven mixing caused by adding raw materials with a particle size ≤0.088 first, which would cause them to settle at the bottom of the raw material. The converter slag-blocking plug head body coated with a refractory insulation layer is prepared by combining, compounding, stirring, and pressing various refractory raw materials to produce a slag-blocking plug body that does not require the addition of a counterweight iron core. The outer layer of the body is coated with a magnesia refractory insulation layer that is erosion-resistant, high-strength, and has good refractory performance. The completed converter slag-blocking plug head coated with a refractory insulation layer has a bulk density and performance that meets or exceeds that of a slag-blocking plug head with a counterweight iron core. This greatly saves raw material and production costs, improves economic efficiency, reduces molding difficulty, improves molding efficiency, enhances the refractory performance of the slag-blocking plug, and improves the slag-blocking effect of the converter.

[0036] Preferably, in step (1), a high-speed mixer is used for mixing, and the mixing time is 20-25 minutes; in step (4), a small mortar mixer is used for mixing, and the mixing time is 8-18 minutes.

[0037] Preferably, the liquid binder brine in step (4) is magnesium chloride hexahydrate with a density of ρ = 1.3 g / cm³. 3 .

[0038] Preferably, the amount of the liquid binder brine is 38-52% of the total weight of the insulation layer raw materials.

[0039] The beneficial effect of the above technical solution is that the requirements for the quality of raw materials can ensure the performance of the refractory insulation layer.

[0040] Preferably, step (5) involves applying the coating using a scraper, trowel, or a homemade tool.

[0041] The slag-blocking plug head coated with refractory insulation and the slag-blocking plug guide rod are assembled into a complete slag-blocking plug for converters coated with refractory insulation.

[0042] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] 1. This invention discloses a converter slag-blocking plug head coated with a refractory insulation layer, which prepares a slag-blocking plug that does not require the addition of a counterweight iron core, so that its bulk density and performance reach or exceed those of a slag-blocking plug with a counterweight iron core.

[0044] 2. This invention provides a converter slag-blocking plug head coated with a refractory insulation layer, which greatly saves raw material costs and production costs, and improves economic efficiency.

[0045] 3. This invention provides a method for producing a converter slag-blocking plug head coated with an insulation layer. The production of the slag-blocking plug head body does not require any changes to the mold or production process. It only requires removing the counterweight iron core from the existing mold and replacing it with a well-mixed plug head body material for molding. The insulation layer coating process of the slag-blocking plug head is simple to operate and easy to apply.

[0046] 4. The present invention provides a converter slag-blocking plug with a coated insulation layer. The converter slag-blocking plug has a coated refractory insulation layer, which is resistant to erosion and scouring, has high overall density, good refractory performance, and excellent slag-blocking effect. Detailed Implementation

[0047] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Example 1

[0049] The raw materials of the converter slag retainer plug body, by weight percentage, include: 33% 3-6mm iron ore, 30% 1-3mm iron ore, 15% 0-1mm 97.5 fused magnesia, 15% 200-mesh 97.5 fused magnesia powder, 3% 2.5μm active alumina micro powder, 2% 0.5μm 96-silica ultrafine powder, and 2% liquid binder phenolic resin;

[0050] The raw materials for the refractory insulation layer coated on the plug body, by weight percentage, include: 30% 0-0.5mm 95 medium-grade magnesia, 60% 325-mesh lightly calcined active magnesium powder, 8% 325-mesh Guangxi white clay, 2% pure calcium aluminate cement, and an additional ρ = 1.3g / cm³. 3 50% saturated magnesium chloride hexahydrate solution;

[0051] A method for preparing a converter slag-blocking plug head coated with a refractory insulation layer includes the following steps:

[0052] (1) Weigh each raw material according to the weight ratio of the raw material of the plug body, mix them in a high-speed mixer for 22 minutes, and add the raw material with a particle size ≥0.088mm first, then add the raw material with a particle size ≤0.088mm, dry mix for 4 minutes, add the liquid binder phenolic resin and mix at high speed for 18 minutes to obtain the mixture.

[0053] (2) Press the mixture from step (1) into shape using a friction brick press with a capacity of ≥1000 tons according to the molding process requirements;

[0054] (3) After being pressed and molded, the plug body is obtained through drying, sorting and assembly processes;

[0055] (4) Based on the weight required for coating the plug body with the refractory insulation layer as described in step (3), weigh the refractory insulation layer raw materials according to the weight ratio, and mix them for 12 minutes using a small mortar mixer. The amount mixed at one time should be used up within 30 minutes. After dry mixing for 4 minutes, add ρ = 1.3g / cm 3 Mix magnesium chloride hexahydrate solution wet for 8 minutes to obtain refractory insulation slurry. Stir the mixed slurry evenly, ensuring it is consistent throughout and has a suitable consistency for application.

[0056] (5) Use a scraper, trowel or homemade tool to take the refractory insulation slurry from step (4) and apply it evenly to the body of the slag-blocking plug head, with a coating thickness of 4mm.

[0057] (6) The coated slag-blocking plug head is dried and sorted according to the production process to obtain the finished product.

[0058] Example 2

[0059] The raw materials of the converter slag retainer plug head body include, by weight percentage: 33% 3-6mm iron ore, 30% 1-3mm iron ore, 15% 0-1mm 97.5 fused magnesia, 20% 200 mesh 97.5 fused magnesia powder, and 2% liquid binder phenolic resin.

[0060] The raw materials for the refractory insulation layer coated on the plug body, by weight percentage, include: 30% 0-0.5mm 95 medium-grade magnesia, 60% 325-mesh lightly calcined active magnesium powder, 8% 325-mesh Guangxi white clay, 2% pure calcium aluminate cement, and an additional ρ = 1.3g / cm³. 3 50% saturated magnesium chloride hexahydrate solution;

[0061] The preparation method of the converter slag-blocking plug head coated with refractory insulation layer is the same as in Example 1.

[0062] Example 3

[0063] The raw materials of the converter slag retainer plug body, by weight percentage, include: 33% 3-6mm iron ore, 30% 1-3mm iron ore, 15% 0-1mm 97.5 fused magnesia, 18% 200-mesh 97.5 fused magnesia powder, 2% 0.5μm 96-silica ultrafine powder, and 2% liquid binder phenolic resin.

[0064] The raw materials for the refractory insulation layer coated on the plug body, by weight percentage, include: 30% 0-0.5mm 95 medium-grade magnesia, 60% 325-mesh lightly calcined active magnesium powder, 5% 325-mesh Guangxi white clay, 5% pure calcium aluminate 71 cement, and an additional ρ = 1.3g / cm³. 350% saturated magnesium chloride hexahydrate solution;

[0065] The preparation method of the converter slag retainer head coated with refractory insulation layer is the same as in Example 1.

[0066] Comparative Example 1

[0067] The raw materials of the converter slag retainer plug body, by weight percentage, include: 64.5% 0-6mm iron ore, 12% 200-mesh iron powder, 20% 200-mesh 97.5 fused magnesia powder, and 3.5% water glass;

[0068] The raw materials of the refractory insulation layer coated on the plug body, by weight percentage, include: 20% 0-0.5mm 95 medium-grade magnesia, 66% 325 mesh light-burned active magnesium powder, 12% 325 mesh Guangxi white clay, 0.8% dextrin, and 1.2% carboxymethyl cellulose (CMC).

[0069] Comparative Example 2

[0070] The raw materials of the converter slag retainer plug head body include, by weight percentage: 68% 0-6mm iron ore, 10% 200-mesh iron powder, 19% 200-mesh 97.5 fused magnesia powder, and 3% phenolic resin.

[0071] The raw materials for the refractory insulation layer coated on the plug body, by weight percentage, include: 20% 0-0.5mm 95 medium-grade magnesia, 50% 240-mesh 95 medium-grade magnesia, 20% 325-mesh lightly calcined activated magnesium powder, 8% 325-mesh Guangxi white clay, 0.8% dextrin, 1.2% carboxymethyl cellulose (CMC), and an additional ρ = 1.3 g / cm³. 3 A 50% saturated brine solution.

[0072] Comparative Example 3

[0073] The raw materials of the converter slag retainer plug body, by weight percentage, include: 28% 3-6mm iron ore, 25% 1-3mm iron ore, 17% 0-1mm iron ore, 10% 200-mesh iron powder, 17% 200-mesh 97.5 fused magnesia powder, and 3% phenolic resin.

[0074] The raw materials of the refractory insulation layer coated on the plug body, by weight percentage, include: 20% 0-0.5mm 95 medium-grade magnesia, 66% 325 mesh light-burned active magnesium powder, 12% 325 mesh Guangxi white clay, 0.8% dextrin, 0.6% carboxymethyl cellulose (CMC), and 0.6% hydroxypropyl methyl cellulose.

[0075] The physicochemical properties of the iron ore, activated alumina micro powder, 97.5 fused magnesia, 96-silica ultrafine powder, and liquid phenolic resin binder used in the converter slag-blocking plug head body in the embodiment are shown in the table below.

[0076] Table 1 shows the physicochemical properties of the converter slag baffle plugs used in Examples 1-3.

[0077] Table 1

[0078]

[0079] After the raw materials in Table 1 are made into the converter slag retainer head body, they meet the performance shown in Table 2.

[0080] Table 2 shows the physical and chemical properties of the converter slag baffle plug head.

[0081] Table 2

[0082]

[0083] Table 3 shows the test indicators for the converter slag baffle plug body in Examples 1-3.

[0084] Table 3

[0085]

[0086] The physicochemical properties of the refractory material used in the heat insulation layer of the converter slag plug head body in Examples 1-3, including 95% medium-grade magnesia (or MgO% ≥ 95% magnesia), lightly calcined active magnesia powder 325 mesh, and Guangxi white clay 325 mesh, are shown in Table 4.

[0087] Table 4 shows the physical and chemical properties of the refractory insulation layer material coated on the furnace slag baffle plug body in Examples 1-3.

[0088] Table 4

[0089] 95 medium-grade magnesia 1.80 2.37 2.45 95.02 0.32 Lightly calcined activated magnesia powder 0.21 1.05 1.51 2.64 91.06 3.20 Guangxi white clay 32.20 1.97 0.12 56.00 0.50 13.00

[0090] After the raw materials in Table 4 are converted into insulation layers, they meet the performance requirements shown in Table 5.

[0091] Table 5 shows the physicochemical properties of the refractory insulation layer material coated on the body of the converter slag baffle plug in Examples 1-3.

[0092] Table 5

[0093]

[0094] Table 6 shows the test indicators of the refractory insulation layer coated on the body of the converter slag baffle plug in Examples 1-3.

[0095] Table 6

[0096]

[0097]

[0098] Table 7 shows the test indicators for the converter slag baffle plug body in Comparative Examples 1-3.

[0099] Table 7

[0100]

[0101] Table 8 shows the test indicators of the refractory insulation layer coated on the body of the converter slag baffle plug in Comparative Examples 1-3.

[0102] Table 8

[0103]

[0104] The bulk density of the converter slag-blocking plug head coated with refractory insulation layer in Examples 1-2 of this invention is 3.52 g / cm³. 3 The slag-blocking plug assembled with the guide rod was tested at the tapping outlet of a 180T converter in a steel plant and achieved good slag-blocking effect. It can be expanded for testing based on the usage situation.

[0105] The bulk density of the converter slag-blocking plug head coated with insulation layer in Embodiment 3 of the present invention is 3.55 g / cm³. 3 The slag-blocking plug, assembled with the guide rod, was used for slag blocking at the tapping port of a 120T converter in a steel plant in Liaoning Province. The slag blocking effect was good and it was recognized by the steel plant. It is now in normal use.

[0106] As shown in Tables 7 and 8, the slag-blocking plugs prepared in Comparative Examples 1-3 have low strength, are difficult to mold, and crack when coated, thus failing to meet the requirements for use.

[0107] As can be seen from the examples, comparative examples, and usage results, the converter slag-blocking plug head coated with a refractory insulation layer provided by this invention makes a practical and innovative choice in the selection of raw materials for the plug head body. The main raw material, iron ore, is combined, compounded, stirred, and machine-pressed with various refractory raw materials, replacing the addition of a counterweight iron core, resulting in a bulk density of 3.4-4.2 g / cm³ for the converter slag-blocking plug head body. 3 This meets the requirements of steel plants for slag blocking at the end of the molten steel discharge process, thus achieving the goal of producing clean steel.

[0108] The converter slag-blocking plug head of this invention uses iron ore, a raw material that is abundant and inexpensive, as its main raw material, thereby reducing production costs and significantly improving economic efficiency. Furthermore, iron ore tailings can meet the requirements, which also has a positive effect on waste utilization and environmental protection.

[0109] This invention provides a converter slag-blocking plug head coated with a refractory insulation layer, the bulk density of which is 3.4-4.2 g / cm³. 3 When assembled with the guide rod, the slag plug has a high overall density, good fire resistance, erosion resistance, and excellent slag-blocking effect during use.

[0110] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0111] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A converter slag-blocking plug head coated with a refractory insulation layer, comprising: The converter slag-blocking plug head body and the refractory insulation layer, wherein the converter slag-blocking plug head body does not contain a counterweight iron core, and wherein the refractory insulation layer is coated on the outer surface of the converter slag-blocking plug head body, characterized in that the raw materials of the converter slag-blocking plug head body, by weight percentage, are: 25-45% 3-6mm iron ore, 20-40% 1-3mm iron ore, 10-20% 1mm 97.5 fused magnesia, 10-30% 200-mesh 97.5 fused magnesia powder, 0-5% activated alumina micro powder, 0-5% 96-silica ultrafine powder, and 2-5% liquid binder phenolic resin; The raw materials of the refractory insulation layer are as follows by weight percentage: 20-40% of 0-0.5mm 95 medium-grade magnesia, 50-70% of 325-mesh light-burned active magnesium powder, 3-10% of 325-mesh Guangxi white clay, and 3-8% of pure calcium aluminate 71 cement.

2. The converter slag-blocking plug head coated with a refractory insulation layer according to claim 1, characterized in that, The iron ore contains ≥69% Fe2O3 and has a particle density ρ ≥4.6 g / cm³. 3 ; The 97.5% fused magnesia contains ≥97.5% MgO. The active alumina micro powder contains ≥98% Al2O3 and has a particle size of D50≤2.5μm; The 96-silica ultrafine powder contains ≥96% SiO2 and has a particle size of D50≤0.5μm.

3. The converter slag-blocking plug head coated with a refractory insulation layer according to claim 1, characterized in that, The MgO content in the 95-grade magnesia is ≥95%; The MgO content in the lightly calcined active magnesium powder is ≥91%; The Al2O3 content in the Guangxi white clay is ≥30%; The pure calcium aluminate 71 cement has an Al2O3 content of ≥71%.

4. The converter slag-blocking plug head coated with a refractory insulation layer according to claim 1, characterized in that, The chemical composition of the converter slag-blocking plug body, by weight percentage, is Fe2O3≥45%, MgO≥32%, and the density of the plug body is 3.4-4.2 g / cm³. 3 .

5. The converter slag-blocking plug head coated with a refractory insulation layer according to claim 1, characterized in that, The chemical composition of the refractory insulation layer, by weight percentage, is MgO ≥ 82%.

6. A method for preparing a converter slag-blocking plug head coated with a refractory insulation layer according to any one of claims 1-5, characterized in that, Includes the following steps: (1) Weigh each raw material according to the weight ratio of the raw material of the plug body, stir and mix, and add the raw material in the following order: first add the raw material with a particle size ≥0.088mm, then add the raw material with a particle size <0.088mm, dry mix for 3-8 minutes, add the liquid binder phenolic resin and mix at high speed for 20-25 minutes to obtain the mixture; (2) Press the mixture from step (1) into shape using a friction brick press with a capacity of ≥1000 tons; (3) After being pressed and molded, the plug body is obtained through drying, sorting and assembly processes; (4) According to the weight required for coating the plug body with refractory insulation layer as described in step (3), weigh the refractory insulation layer raw materials according to the weight ratio, stir and mix. The amount of mixing at one time should be used up within 30 minutes. After dry mixing for 3-8 minutes, add liquid binder brine and wet mix for 5-10 minutes to obtain refractory insulation layer slurry. (5) Apply the mud material from step (4) evenly to the body of the slag-blocking plug head, with a coating thickness of 3-5 mm; (6) The coated slag-blocking plug head is dried and sorted to obtain the finished product.

7. The method for preparing a converter slag-blocking plug head coated with a refractory insulation layer according to claim 6, characterized in that, In step (1), a high-speed mixer is used for stirring and mixing; in step (4), a small mortar mixer is used for stirring and mixing, and the mixing time is 8-18 minutes.

8. The method for preparing a converter slag-blocking plug head coated with a refractory insulation layer according to claim 6, characterized in that, In step (4), the liquid binder brine is magnesium chloride hexahydrate, with a density of ρ = 1.3 g / cm³. 3。 9. The method for preparing a converter slag-blocking plug head coated with a refractory insulation layer according to claim 8, characterized in that, The amount of the liquid binder brine used is 38-52% of the total weight of the insulation layer raw materials.

10. The method for preparing a converter slag-blocking plug head coated with a refractory insulation layer according to claim 6, characterized in that, In step (5), a scraper or trowel is used for application.

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