阅读说明：本技术 一种无碳钢包下水口及其制备方法 (Carbon-free ladle down nozzle and preparation method thereof ) 是由 方岩震 余西平 赵锋 于 2020-12-31 设计创作，主要内容包括：本发明公开了一种无碳钢包下水口及其制备方法,属于耐火材料技术领域,其组成成分及重量百分比为：MAS-76铝镁尖晶石60％-64％和共磨粉36％-40％,总百分比为100％；外加占总重量百分比为4％～5％的热固酚醛树脂结合剂,其中共磨粉包括10％～18％MAS-76铝镁尖晶石细粉、7％～13％α-Al-2O-3微粉、8％～10％锆英石细粉和5％金属硅粉。本发明引入MAS-76铝镁尖晶石作为颗粒骨料,通过无碳化,提高钢水洁净度质量,改善产品性能,降低生产成本；无碳钢包下水口具有耐高温性能、抗渣性能、抗剥落性能,且下水口表面分布有更多的MAS-76铝镁尖晶石颗粒和细粉,具有很好的抗冲刷性能。(The invention discloses a carbon-free ladle down nozzle and a preparation method thereof, belonging to the technical field of refractory materials, and comprising the following components in percentage by weight: 60% -64% of MAS-76 aluminum magnesium spinel and 36% -40% of co-milled powder, wherein the total percentage is 100%; the thermosetting phenolic resin binder accounts for 4 to 5 percent of the total weight, wherein the cofiller powder comprises 10 to 18 percent of MAS-76 aluminum magnesium spinel fine powder and 7 to 13 percent of alpha-Al 2 O 3 Micro powder, 8-10% of zircon fine powder and 5% of metal silicon powder. The invention introduces MAS-76 aluminum magnesium spinel as particle aggregate, and improves steel through non-carbonizationThe water cleanliness quality improves the product performance and reduces the production cost; the carbon-free ladle down nozzle has high temperature resistance, slag resistance and spalling resistance, and the surface of the down nozzle is distributed with more MAS-76 aluminum magnesium spinel particles and fine powder, so the carbon-free ladle down nozzle has good scour resistance.)

1. A carbon-free ladle down nozzle is characterized by comprising 60% -64% of MAS-76 aluminum magnesium spinel, and the components and weight percentage of the raw materials are as follows: 15% of MAS-76 aluminum magnesium spinel with the grain diameter of 5-3 mm, 30% of MAS-76 aluminum magnesium spinel with the grain diameter of 3-1 mm and 15% -19% of MAS-76 aluminum magnesium spinel with the grain diameter of 1-0 mm.

2. The carbon-free ladle nozzle according to claim 1, wherein the carbon-free ladle nozzle raw material further comprises 36-40 wt% of co-ground powder, and the sum of the weight percentage of co-ground powder and MAS-76 aluminum magnesium spinel is 100%; and a thermosetting phenolic resin binder accounting for 4-5 percent of the total weight is additionally added.

3. The carbon-free ladle nozzle as defined in claim 2, wherein the co-milled powder comprises 10-18% MAS-76 MgO spinel fine powder and 7-13% alpha-Al₂O₃Micro powder, 8-10% of zircon fine powder and 5% of metal silicon powder.

4. The carbon-free ladle nozzle as recited in claim 3, wherein the MAS-76 MgO spinel fine powder has a particle size of 325 meshes, and the MAS-76 MgO spinel has the following chemical components and contents: al (Al)₂O₃75.58% of the total content of the components (A) and (B), 23.54% of the content of MgO, 0.3% of the content of CaO, and 0.3% of the content of SiO₂0.25% of (C), Fe₂O₃The content of (B) is 0.23%.

5. The carbon-free ladle nozzle according to claim 3, wherein the MAS-76 aluminum magnesium spinel and the MAS-76 aluminum magnesium spinel fine powder are formed by sintering industrial MAS-76 aluminum magnesium spinel in an ultrahigh temperature tunnel kiln at a high temperature of more than 1800 ℃ through a multi-stage homogenization process.

6. The carbon-free ladle drain nozzle according to claim 3, wherein the α -Al is₂O₃The particle size of the micro powder is 0-2 mu m; the alpha-Al₂O₃The micro powder comprises the following chemical components in percentage by weight: al (Al)₂O₃The content of (A) is more than or equal to 99.0 percent, and SiO₂Content of (B) is less than or equal to 0.1%, Fe₂O₃The content of the sodium-containing complex is less than or equal to 0.08 percent, and Na₂O+K₂The content of O is less than or equal to 0.3 percent.

7. The carbon-free ladle nozzle according to claim 3, wherein the fine zircon powder comprises the following chemical components in percentage by weight: ZrO (ZrO)₂66.25% of SiO₂32.50% of TiO₂0.33% of (C), Al₂O₃0.37% of (C), Fe₂O₃0.16% of (A), 0.05% of CaO, 0.02% of MgO, and Na₂0.01% of O, K₂The content of O is 0.01 percent; the particle size of the fine zircon powder is 325 meshes.

8. The carbon-free ladle drain nozzle according to claim 3, wherein the metal silicon powder comprises the following chemical components in percentage by weight: the content of Si is 98.6%, the content of Fe is 0.54%, the content of Al is 0.49%, and the content of Ca is 0.36%; the particle size of the metal silicon powder is 325 meshes.

9. The method for preparing the carbon-free ladle nozzle according to any one of claims 1 to 8, comprising the following steps:

step one, preparing co-ground powder: MAS-76 fine magnesia alumina spinel powder and alpha-Al are mixed according to the weight percentage₂O₃Uniformly mixing the micro powder, the fine zircon powder and the metal silicon powder to prepare co-milled powder;

step two, proportioning the granular materials: uniformly mixing MAS-76 aluminum-magnesium spinel with the particle size of 5-3 mm, MAS-76 aluminum-magnesium spinel with the particle size of 3-1 mm and MAS-76 aluminum-magnesium spinel with the particle size of 1-0 mm according to weight percentage to obtain particle ingredients;

step three, mixing materials: after the particles are dry-mixed for 2-3 minutes, slowly adding a thermosetting phenolic resin binding agent for wet mixing for 5-8 minutes, finally adding the co-ground powder, and after mixing for 50-60 minutes, discharging and grinding to obtain a mixture;

step four, forming: pressing and molding the mixture into a semi-finished blank;

step five, drying: naturally airing the green body for 8 hours, and then placing the green body in a tunnel natural gas drying kiln for drying according to a set curve: the initial temperature of the material entering the cellar is 30 ℃, and the temperature is increased from 30 ℃ to 80 ℃ within 0-4 hours; raising the temperature from 80 ℃ to 120 ℃ within 4-7 hours; raising the temperature from 120 ℃ to 150 ℃ within 7-9 hours; raising the temperature from 150 ℃ to 180 ℃ within 9-11 hours; raising the temperature from 180 ℃ to 210 ℃ within 11-13 hours, and preserving the heat for 16 hours; the total drying time was 37 hours;

step six, casing: covering the blank obtained in the fifth step with a casing, rotationally plastering mortar on the outer wall of the lower nozzle, covering a steel shell, reversely buckling the lower nozzle in a tool, pressing to a set position, and taking out the nozzle; pressing a shell, cleaning the upward part of the lower nozzle to overflow the fire clay, taking the lower nozzle out of the tool, taking the lower nozzle out, and placing the upper opening downward to clean another fire clay; performing first inspection on the product, placing the water outlet on the frame with a big head downwards after the product is qualified, and adjusting a limiting block when the product is unqualified or tapping the iron shell by using a tool to make the product qualified;

step seven, drying the casing: the water gap is naturally cured for 4-8 hours at room temperature after the casing is sleeved, the product is dried by adopting a natural gas tunnel drying kiln at present, and the drying temperature curve is as follows: raising the temperature from 30 ℃ to 80 ℃ within 0-1 hour; raising the temperature from 80 ℃ to 120 ℃ within 2-3 hours; raising the temperature from 120 ℃ to 150 ℃ within 4-5 hours, and keeping the temperature for 8 hours; the total drying time was 13 hours;

step eight, packaging: and after drying, taking out of the kiln, airing to room temperature, checking to be qualified, and packaging.

10. The method for preparing the carbon-free steel ladle nozzle according to claim 9, wherein the granular materials are added into a wet mill for dry mixing in the third step, and the mixture is pressed and formed on a 630t electric spiral brick press in the fourth step.

Technical Field

The invention belongs to the technical field of refractory materials, and particularly relates to a carbon-free ladle down nozzle and a preparation method thereof.

Background

In the process of smelting molten steel by a steel ladle and a converter, an aluminum-carbon steel ladle nozzle is generally adopted at present, the molten steel smelting purity is influenced by the introduction of carbon due to the use of aluminum carbon, the cost is higher, the product is more favorable for improving the cleanliness of the molten steel through non-carbonization of the nozzle, and meanwhile, MAS-76 aluminum magnesium spinel is formed by sintering at a high temperature of more than 1800 ℃ in an ultrahigh-temperature tunnel kiln through a multi-stage homogenization process, has large volume density, high mineral phase content, good crystal grain development, uniform structure and stable quality, and provides the high-performance carbon-free steel ladle nozzle with good erosion resistance, stripping resistance, slag resistance and thermal shock stability. The refractory materials include refractory bricks, refractory cotton, sliding plates, etc., and the required performance of the refractory materials is different according to the application environment.

Through search, the patent publication number is CN111018496A, the publication date is 2020, 04, 17, and the patent name is a carbon-free magnesium dolomite sliding plate and a preparation method and application thereof. The invention discloses a carbon-free magnesium dolomite slide plate and a preparation method and application thereof, and belongs to the technical field of refractory materials. The sliding plate comprises the following raw materials: 60-64 wt% of a granular material mainly comprising magnesium dolomite sand and 36-40 wt% of co-ground powder, wherein the total percentage is 100%, and an anhydrous resin binder accounting for 4-5 wt% of the total weight is added; wherein the co-milled powder comprises 10-18 wt% of magnesium dolomite fine powder and 3-7 wt% of a-Al₂O₃Micro powder, 4-6 wt% of zirconia fine powder, 8-10 wt% of zirconite fine powder and 5 wt% of metal silicon powder. The magnesium dolomite sand and the fine powder introduced into the sliding plate are industrial high-temperature calcination-stable magnesium dolomite, and the non-carbonization improves the molten steel cleanliness and the molten steel quality during smelting, improves the product performance and reduces the production cost. The method has the disadvantages that the dolomite sand contains CaO and is easy to hydrate, a liquid binding agent without water or with as little water content as possible is required to be adopted in the preparation process, the product is required to be subjected to oil immersion or wax immersion surface treatment and then is subjected to vacuum packaging, the storage cost is increased, the dolomite sand is applied to a sliding plate, the control requirement on the production process of raw materials and pug is higher, in other words, the dolomite sand has high raw material activity requirement, the dolomite sand is generally prepared by adopting electrically fused dolomite sand which is prepared by the reaction of magnesium oxide and aluminum oxide, the temperature and the reaction condition are required to be accurately controlled in the process,and the requirements on the reactor are higher, and the magnesium aluminate spinel has a uniform structure and more stable quality.

For another example, the magnesium spinel brick has a patent publication number of CN106946550B, a publication date of 2019, 08 and 12, and a patent name of the magnesium spinel brick is a magnesium spinel brick with excellent anti-stripping performance and a preparation method of the magnesium spinel brick. The invention discloses a magnesia spinel brick with excellent anti-stripping performance and a preparation method thereof, wherein the preparation method comprises the following steps: 1) mixing magnesia particles with different granularities and spinel combined magnesia particles with carbon black to ensure that the carbon black is uniformly adsorbed on the surfaces of the particles; 2) magnesia and spinel combined magnesia particles subjected to carbon black adsorption modification treatment are used as aggregates, magnesia fine powder and spinel micro powder are used as matrixes, and metal Al, simple substance Si and B are added₄C, and the like, and a high-temperature sintering agent, and is prepared by uniformly mixing lignin solution, phenolic resin or magnesium aluminate cementing agent serving as a binding agent, pressing and molding, and baking at low temperature. The invention utilizes carbon black to carry out surface modification on aggregate, introduces spinel and magnesia, obviously reduces the thermal expansion coefficient of magnesium spinel bricks on the premise of not influencing slag resistance, simultaneously optimizes the microstructure structure of products, is applied to RH furnace linings, can obviously improve the anti-stripping performance of the products and prolongs the service life. The method has the disadvantages that the magnesite is taken as the main raw material, the magnesite is easy to hydrate in a humid environment, the main raw material of the magnesite is MgO, the MgO has high thermal expansion rate, and the prepared product is easy to crack.

Disclosure of Invention

1. Problems to be solved

Aiming at the problems that in the prior art, magnesia is used as a main raw material, the thermal expansion rate of the material is high, and cracks are easy to generate, the invention provides the carbon-free ladle down nozzle, MAS-76 magnesia alumina spinel and MAS-76 magnesia alumina spinel fine powder obtained by high-temperature sintering are used as main raw materials, the volume density is large, the mineral phase content is high, the crystal grain development is good, the structure is uniform, the quality is stable, the erosion resistance, the stripping resistance, the slag corrosion resistance and the thermal shock stability are good, the cleanliness of molten steel is effectively improved through non-carbonization, and more MAS-76 magnesia spinel particles and MAS-76 magnesia spinel fine powder are distributed on the surface of the down nozzle, so that the carbon-free ladle down nozzle has good scouring resistance.

2. Technical scheme

In order to solve the problems, the technical scheme adopted by the invention is as follows:

a carbon-free ladle down nozzle comprises 60% -64% of MAS-76 aluminum magnesium spinel, and comprises the following raw materials in percentage by weight: 15% of MAS-76 aluminum magnesium spinel with the grain diameter of 5-3 mm, 30% of MAS-76 aluminum magnesium spinel with the grain diameter of 3-1 mm and 15% -19% of MAS-76 aluminum magnesium spinel with the grain diameter of 1-0 mm.

Wherein MAS-76 is Al₂O₃The content of the (5) is 76%, MAS is short for Magnesia-aluminum Spinel, and MAS-76 is MgO and Al₂O₃As raw material, artificially synthesized spinel refractory material, wherein Al₂O₃75-77%, MgO 22-24%, CaO not more than 0.4%, SiO₂Content of (B) is less than or equal to 0.3%, Fe₂O₃The content of (B) is less than or equal to 0.3 percent.

Furthermore, the particle size of the MAS-76 aluminum magnesium spinel fine powder is 325 meshes, and the MAS-76 aluminum magnesium spinel comprises the following chemical components in percentage by weight: al (Al)₂O₃75.58% of the total content of the components (A) and (B), 23.54% of the content of MgO, 0.3% of the content of CaO, and 0.3% of the content of SiO₂0.25% of (C), Fe₂O₃The content of (B) is 0.23%.

Furthermore, the raw material of the carbon-free ladle drain nozzle also comprises 36 to 40 weight percent of co-ground powder, and the sum of the co-ground powder and MAS-76 aluminum-magnesium spinel is 100 percent; and a thermosetting phenolic resin binder accounting for 4-5 percent of the total weight is additionally added.

Further, the co-ground powder comprises 10-18% of MAS-76 aluminum magnesium spinel fine powder and 7-13% of alpha-Al₂O₃Micro powder, 8-10% of zircon fine powder and 5% of metal silicon powder.

alpha-Al used in additives₂O₃The addition amount of the micro powder is 7-13%, 9-17% of liquid phase amount is formed at 1480 ℃, the compactness is improved, and the slag corrosion resistance of a ladle nozzle is further improved.

Furthermore, the MAS-76 aluminum magnesium spinel and the MAS-76 aluminum magnesium spinel fine powder are formed by sintering industrial MAS-76 aluminum magnesium spinel in an ultrahigh temperature tunnel kiln at a high temperature of more than 1800 ℃ through a multistage homogenization process, have large volume density, high mineral phase content, good grain growth, uniform structure and stable quality, and provide the MAS-76 aluminum magnesium spinel and the MAS-76 aluminum magnesium spinel with good erosion resistance, stripping resistance, slag corrosion resistance and thermal shock stability.

Further, the α -Al₂O₃The particle size of the micro powder is 0-2 mu m; the alpha-Al₂O₃The micro powder comprises the following chemical components in percentage by weight: al (Al)₂O₃The content of (A) is more than or equal to 99.0 percent, and SiO₂Content of (B) is less than or equal to 0.1%, Fe₂O₃The content of the sodium-containing complex is less than or equal to 0.08 percent, and Na₂O+K₂The content of O is less than or equal to 0.3 percent.

Furthermore, the chemical components and contents of the zircon fine powder are as follows: ZrO (ZrO)₂66.25% of SiO₂32.50% of TiO₂0.33% of (C), Al₂O₃0.37% of (C), Fe₂O₃0.16% of (A), 0.05% of CaO, 0.02% of MgO, and Na₂0.01% of O, K₂The content of O is 0.01 percent; the particle size of the fine zircon powder is 325 meshes.

The tapping temperature of the molten steel is 1650-1700 ℃, and by utilizing the tapping temperature, the zircon fine powder can form CaZrO with CaO at high temperature₃And CS₃The formation of these new phases activates the crystal lattice and promotes the growth of crystal grains.

Furthermore, the metal silicon powder comprises the following chemical components in percentage by weight: the content of Si is 98.6%, the content of Fe is 0.54%, the content of Al is 0.49%, and the content of Ca is 0.36%; the particle size of the metal silicon powder is 325 meshes.

The thermosetting phenolic resin is used as a bonding agent, the metal silicon powder is uniformly dispersed in the lower nozzle and oxidized to generate silicon dioxide, on one hand, the strength of the lower nozzle is increased through a silicon dioxide gel system, and simultaneously, the silicon dioxide gel system reacts with alpha-Al at high temperature₂O₃The micro-powder reaction is used for producing mullite substance with excellent thermal shock stability, further improving the high-temperature strength of the lower nozzle andthermal shock stability.

At present, a lower nozzle used by a common steel ladle sliding mechanism is made of aluminum carbon, the main components of the system are aluminum carbon materials such as aluminum oxide, metal aluminum, carbon black, graphite and the like, the use requirement can be met when common carbon steel is smelted, but the steel-making requirements of clean steel and special steel which cannot be rapidly increased are met, and the alkaline steel slag scouring and erosion resistance is poor.

In addition, when the aluminum carbon drain nozzle is used for smelting steel grades with high requirements on carbon content, such as clean steel, stainless steel and the like, the ordinary aluminum carbon drain nozzle cannot meet the technical requirements on carbon content of steel grades in steel plants due to the introduction of graphite carbon and pitch carbon. The invention starts from aluminum reduction and carbon removal, and changes MAS-76 aluminum-magnesium spinel raw material with high mineral phase content, good crystal grain development, uniform structure, erosion resistance, stripping resistance, slag corrosion resistance and good thermal shock stability into a brand new clean steel drain nozzle material system for a ladle to meet the requirements of steel-making cleanliness and high-quality steel.

The invention also aims to provide a preparation method of the carbon-free ladle down nozzle, which comprises the following steps:

step one, preparing co-milled powder: MAS-76 fine magnesia alumina spinel powder and alpha-Al are mixed according to the weight percentage₂O₃Uniformly mixing the micro powder, the fine zircon powder and the metal silicon powder to prepare co-milled powder;

step two, proportioning the granular materials: uniformly mixing MAS-76 aluminum-magnesium spinel with the particle size of 5-3 mm, MAS-76 aluminum-magnesium spinel with the particle size of 3-1 mm and MAS-76 aluminum-magnesium spinel with the particle size of 1-0 mm according to weight percentage to obtain particle ingredients;

step three, mixing materials: dry-mixing the particle aggregate for 2-3 minutes, slowly adding a thermosetting phenolic resin binding agent, wet-mixing for 5-8 minutes, finally adding the co-ground powder, mixing for 50-60 minutes, and then discharging and grinding to obtain a mixture;

step four, forming: pressing and molding the mixture into a semi-finished blank;

step five, drying: naturally airing the green body for 8 hours, then placing the green body in a tunnel natural gas drying kiln for drying according to a set curve, wherein the initial temperature of the green body entering the kiln is 30 ℃, and the temperature is increased from 30 ℃ to 80 ℃ within 0-4 hours; raising the temperature from 80 ℃ to 120 ℃ within 4-7 hours; raising the temperature from 120 ℃ to 150 ℃ within 7-9 hours; raising the temperature from 150 ℃ to 180 ℃ within 9-11 hours; raising the temperature from 180 ℃ to 210 ℃ within 11-13 hours, and preserving the heat for 16 hours; the total drying time was 37 hours; inspecting the product after the product is taken out of the kiln, and selecting the product with qualified size and appearance to enter the next procedure;

step six, casing: the method comprises the following steps of (1) sleeving a dried qualified product, rotationally smearing proper fire clay on the outer wall of a lower nozzle, extruding the fire clay from the upper part and the lower part of the lower nozzle after the lower nozzle is pressed, covering a steel shell on the steel shell, then reversely buckling the lower nozzle in a tool, pressing to a set position, taking out the lower nozzle, ensuring that the fire clay is extruded from the upper part and the lower part of a sliding plate after the lower nozzle is pressed, taking out the nozzle after the upper part of the lower nozzle overflows the fire clay by using a tool and cleaning, taking out the lower nozzle, placing the upper opening downwards to clean another fire clay, paying attention to ensure that the lower nozzle is clean during cleaning, performing first inspection on the product, placing the lower nozzle downwards on a frame with a large end after the product is qualified, and adjusting a limiting block or using the tool iron shell to ensure that the;

step seven, drying the casing: and (3) naturally curing the sheathed lower nozzle for 4-8 hours at room temperature, and drying the product by using a natural gas tunnel drying kiln at present, wherein the drying temperature curve is as follows: raising the temperature from 30 ℃ to 80 ℃ within 0-1 hour; raising the temperature from 80 ℃ to 120 ℃ within 2-3 hours; raising the temperature from 120 ℃ to 150 ℃ within 4-5 hours, and keeping the temperature for 8 hours; the total drying time was 13 hours;

step eight, packaging: and after drying, taking out of the kiln, airing to room temperature, checking the size and the appearance according to the drawing requirements and appearance standards, and boxing and packaging.

Further, in the third step, the granular materials are added into a wet mill for dry mixing, and in the fourth step, the mixture is pressed and molded on a 630t electric spiral brick machine.

The carbon-free ladle down nozzle production process has 8 working procedures, each working procedure of product production sets detailed operation procedures and technological parameter requirements, particularly in the drying working procedure, the natural drying time is determined to be 8 hours, so that part of water is naturally discharged firstly, and the cracking of the product caused by directly entering a kiln for drying is prevented; and the drying temperature curve requirement, especially the control of the temperature rising speed in the low temperature stage, prevent the excessive temperature rising, the crackle of the products is produced; the production process is in a controllable state, and the effective implementation of the technical scheme is ensured.

3. Advantageous effects

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

(1) starting from aluminum reduction and carbon removal, the MAS-76 aluminum-magnesium spinel raw material which has large volume density, high mineral phase content, good crystal grain development, uniform structure, erosion resistance, stripping resistance, slag corrosion resistance and good thermal shock stability is used to form a brand new clean steel drain nozzle material system for a ladle to meet the requirements of steel-making cleanliness and high-quality steel, and the following needs are stated: the MAS-76 aluminum magnesium spinel has large volume density, high mineral phase content, good crystal grain development, uniform structure and stable quality, and compared with the magnesia or corundum adopted in the prior art, the performance of the drainage port is more stable; through a large number of tests and analyses, the inventors considered possible reasons to be: the MAS-76 aluminum magnesium spinel mainly acts in the drain nozzle in a mode of particle aggregate, wherein a small part of MAS-76 aluminum magnesium spinel fine powder can be filled in pores formed by a binder, so that the pores are filled to ensure compact texture; in addition, the MAS-76 magnesium aluminate spinel has high density, can be dispersed at the periphery of a mixture under the action of longitudinal pressure in the mixing process, more MAS-76 magnesium aluminate spinel particles and fine powder are distributed on the surface of the lower nozzle after molding, and the surface of the lower nozzle is in direct contact with molten steel, so that the MAS-76 magnesium aluminate spinel has good anti-scouring performance;

(2) the MAS-76 aluminum magnesium spinel is formed by high-temperature sintering at the temperature of more than 1800 ℃ in an ultrahigh-temperature tunnel kiln through a multistage homogenization process, has large volume density, high mineral phase content, good crystal grain development, uniform structure and stable quality, and provides a material with good erosion resistance, stripping resistance, slag corrosion resistance and thermal shock stability; when the carbon-free ladle drain nozzle is contacted with the slag in the using process, the carbon-free ladle drain nozzle has strong resistance to chemical erosion and infiltration of the slag;

(3) the alpha-Al used in the carbon-free ladle down nozzle₂O₃The addition amount of the micro powder is 7-13%, 9-17% of liquid phase amount is formed at 1480 ℃, the compactness is improved, and the slag corrosion resistance of the ladle nozzle brick is further improved;

(4) according to the invention, thermosetting phenolic resin is used as a binding agent, metal silicon powder is uniformly dispersed in the lower nozzle and oxidized to generate silicon dioxide, so that on one hand, the strength of the lower nozzle is increased through a silicon dioxide gel system, and simultaneously, the mixture reacts with alpha-Al at high temperature₂O₃The micro powder reaction produces mullite substance with excellent thermal shock stability, and further improves the high-temperature strength and the thermal shock stability of the lower nozzle.

Detailed Description

The invention is further described with reference to specific examples. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that various changes to the invention may be made without departing from the spirit and scope of the present invention. The following more detailed description of the embodiments of the invention is not intended to limit the scope of the invention, as claimed, but is presented for purposes of illustration only and not limitation to describe the features and characteristics of the invention, to set forth the best mode of carrying out the invention, and to sufficiently enable one skilled in the art to practice the invention. Accordingly, the scope of the invention is to be limited only by the following claims.

Wherein table 1 shows the particle type and percentage of the ingredients used in the examples of the present invention; table 2 shows the physical and chemical properties and the average service life parameters of the carbon-free ladle down nozzle obtained in the above examples 1 to 4 and the existing aluminum-carbon ladle down nozzle.

Example 1

A carbon-free ladle down nozzle comprises the following components by weight percent: 64 percent of MAS-76 aluminum-magnesium spinel and 36 percent of milling powder, wherein the sum of the weight percentages is 100 percent; additionally adding a thermosetting phenolic resin binder accounting for 5 percent of the total weight, wherein the binderThe milling powder is made of 10% MAS-76 AlMgspinel fine powder and 13% alpha-Al₂O₃The micro powder, 8 percent of zircon fine powder and 5 percent of metal silicon powder are evenly mixed to obtain the material.

The MAS-76 aluminum magnesium spinel and the MAS-76 aluminum magnesium spinel fine powder are formed by sintering MAS-76 aluminum magnesium spinel in an ultrahigh temperature tunnel kiln at the high temperature of more than 1800 ℃ through a multistage homogenization process, have large volume density, high mineral phase content, good crystal grain development, uniform structure and stable quality, and provide a material with good erosion resistance, stripping resistance, slag corrosion resistance and thermal shock stability.

The MAS-76 aluminum magnesium spinel has the particle sizes of 5-3 mm, 3-1 mm and 1-0 mm, and the weight percentages of the particle sizes are as follows: 15% of MAS-76 aluminum magnesium spinel with the grain diameter of 5-3 mm, 30% of MAS-76 aluminum magnesium spinel with the grain diameter of 3-1 mm and 19% of MAS-76 aluminum magnesium spinel with the grain diameter of 1-0 mm; the MAS-76 aluminum magnesium spinel comprises the following chemical components in percentage by weight: al (Al)₂O₃75.58% of the total content of the components (A) and (B), 23.54% of the content of MgO, 0.3% of the content of CaO, and 0.3% of the content of SiO₂0.25% of (C), Fe₂O₃The content of (B) is 0.23%.

The MAS-76 aluminum magnesium spinel fine powder has the particle size of 325 meshes and the weight percentage of 10 percent, and the MAS-76 aluminum magnesium spinel fine powder comprises the following chemical components in percentage by weight: al (Al)₂O₃75.58% of the total content of the components (A) and (B), 23.54% of the content of MgO, 0.3% of the content of CaO, and 0.3% of the content of SiO₂0.25% of (C), Fe₂O₃The content of (B) is 0.23%.

The alpha-Al₂O₃The particle size of the micro powder is 0-2 mu m; the alpha-Al₂O₃The micro powder comprises the following chemical components in percentage by weight: al (Al)₂O₃The content of (A) is more than or equal to 99.0 percent, and SiO₂Content of (B) is less than or equal to 0.1%, Fe₂O₃The content of the sodium-containing complex is less than or equal to 0.08 percent, and Na₂O+K₂The content of O is less than or equal to 0.3 percent.

The zircon fine powder comprises the following chemical components in percentage by weight: ZrO (ZrO)₂66.25% of SiO₂32.50% of TiO₂0.33% of (C), Al₂O₃0.37% of (C), Fe₂O₃0.16% of CaO0.05%, 0.02% MgO, Na₂0.01% of O, K₂The content of O is 0.01 percent; the particle size of the fine zircon powder is 325 meshes.

The metal silicon powder comprises the following chemical components in percentage by weight: the content of Si is 98.6%, the content of Fe is 0.54%, the content of Al is 0.49%, and the content of Ca is 0.36%; the metal silicon powder is 98 metal silicon, the particle size is 325 meshes, and the Si content is 98%.

The preparation method of the carbon-free ladle down nozzle comprises the following steps:

step one, preparing co-milled powder: MAS-76 fine magnesia alumina spinel powder and alpha-Al are mixed according to the weight percentage₂O₃Uniformly mixing the micro powder, the fine zircon powder and the metal silicon powder to prepare co-milled powder;

step two, proportioning the granular materials: uniformly mixing MAS-76 aluminum-magnesium spinel with the particle size of 5-3 mm, MAS-76 aluminum-magnesium spinel with the particle size of 3-1 mm and MAS-76 aluminum-magnesium spinel with the particle size of 1-0 mm according to weight percentage to obtain particle ingredients;

step three, mixing materials: dry-mixing the granular aggregate for 2-3 minutes by using a wet mill, slowly adding a thermosetting phenolic resin binding agent for wet mixing for 5-8 minutes, finally adding the co-ground powder, mixing for 50-60 minutes, and then discharging and grinding to obtain a mixture;

step four, forming: pressing and molding the mixture on a 630t electric spiral brick press to form a semi-finished blank;

step five, drying: naturally airing the green body for 8 hours, then placing the green body in a tunnel natural gas drying kiln for drying according to a set curve, wherein the initial temperature of the green body entering the kiln is 30 ℃, and the temperature is increased from 30 ℃ to 80 ℃ within 0-4 hours; raising the temperature from 80 ℃ to 120 ℃ within 4-7 hours; raising the temperature from 120 ℃ to 150 ℃ within 7-9 hours; raising the temperature from 150 ℃ to 180 ℃ within 9-11 hours; raising the temperature from 180 ℃ to 210 ℃ within 11-13 hours, and preserving the heat for 16 hours; the total drying time was 37 hours; inspecting the product after the product is taken out of the kiln, and selecting the product with qualified size and appearance to enter the next procedure;

step six, casing: coating proper fire clay on the outer wall of a water gap in a rotating mode, taking the fact that the fire clay can be extruded vertically after the water gap is pressed as a standard, covering a steel shell on the steel shell, then reversely buckling the water gap in a tool, pressing the steel shell to a set position, taking out the water gap, ensuring that the fire clay can be extruded vertically by a sliding plate after the shell is pressed, taking out the water gap after the fire clay overflowing from the upward part of the water gap is cleaned by using a tool, taking out the water gap, placing the upper opening downwards to clean another fire clay, paying attention to ensuring that the water gap is clean during cleaning, performing first inspection on a product, placing the water gap downwards on a frame with a large head after the product is qualified, and adjusting a limiting block by an unqualified operator or tapping the iron shell by using a tool to enable the product;

step seven, drying the casing: and (3) naturally curing the sheathed lower nozzle for 4-8 hours at room temperature, and drying the product by using a natural gas tunnel drying kiln at present, wherein the drying temperature curve is as follows: raising the temperature from 30 ℃ to 80 ℃ within 0-1 hour; raising the temperature from 80 ℃ to 120 ℃ within 2-3 hours; raising the temperature from 120 ℃ to 150 ℃ within 4-5 hours, and keeping the temperature for 8 hours; the total drying time was 13 hours;

step eight, packaging: and after drying, taking out of the kiln, airing to room temperature, checking the size and the appearance according to the drawing requirements and appearance standards, and boxing and packaging.

Example 2

The composition and weight percentage of the carbon-free ladle down nozzle of the embodiment are according to the formula shown in the table 1, and the preparation method is the same as the embodiment 1.

Example 3

The composition and weight percentage of the carbon-free ladle down nozzle of the embodiment are according to the formula shown in the table 1, and the preparation method is the same as the embodiment 1.

Example 4

The composition and weight percentage of the carbon-free ladle down nozzle of the embodiment are according to the formula shown in the table 1, and the preparation method is the same as the embodiment 1.

TABLE 1 particle types and percentages of the ingredients used in the examples of the present invention

The carbon-free ladle down nozzle is prepared by the embodiment.

TABLE 2 physicochemical properties and average service life parameters of the carbon-free ladle drain openings obtained in examples 1 to 4 and the existing aluminum-carbon ladle drain openings

As can be seen from table 2, the carbon-free ladle nozzle of the present invention is tried on a large ladle, and after the test is completed, the carbon-free ladle nozzle and the existing product are subjected to the analysis of hole expansion, crack condition, etc., so that the average service life is 3-4 times per block, and the hole expansion rate is: average 5 mm/piece; the average erosion rate was 1.25 mm/time. Through batch use and comparison of the result with the existing product, the average erosion rate of the carbon-free ladle drain nozzle is less than or equal to 2 mm/time, and the erosion rate lower than the existing aluminum-carbon product is more than or equal to 3.5 mm/time; the carbon-free ladle nozzle has good high temperature resistance, thermal shock resistance and slag corrosion resistance.

The above description is a more detailed description of the present invention with reference to specific preferred embodiments, and it is not intended to limit the present invention to the specific embodiments described above. It will be apparent to those skilled in the art that various modifications, additions, substitutions, and the like can be made without departing from the spirit of the invention.