A sealing mastic for slide gates and a method for its preparation

Abstract

The application discloses a sealing mortar for sliding water gap and a preparation method thereof. The sealing mortar for sliding water gap is composed of the following components in parts by mass: blast furnace slag powder 35-45 parts, calcium quicklime fine powder 15-25 parts, graded quartz sand mortar aggregate 30-40 parts, pre-activated composite activator 8-12 parts, sodium silicate-based quick-setting adjusting liquid 5-10 parts, plastic water-retaining fiber 0.5-2 parts, and aluminum powder antioxidant 0.1-0.3 parts. The pre-activated composite activator is prepared by dry blending sodium bentonite and anhydrous potassium carbonate at a mass ratio of 7:3. The pre-activated composite activator is used to modify the slag, and the mortar forms a dense reaction interface in the plastic stage, thereby overcoming the defect of the traditional slag-lime system reaction lag. From initial setting and hardening to high-temperature service, the system always maintains dynamic adhesion with the sliding water gap. In the initial setting stage, oligomeric silicate rapidly penetrates the slag interface to generate a rigid gel skeleton, realizes rapid structure locking, and greatly shortens the water gap installation waiting time.

Description

Technical Field

[0001] This invention belongs to the field of sealing putty technology, specifically relating to a sealing putty for sliding gate nozzles; and more particularly to a method for preparing the sealing putty for sliding gate nozzles. Background Technology

[0002] As a key component for flow control in continuous casting systems, the sliding gate nozzle requires its gap sealing mortar to possess high-temperature bonding, resistance to molten steel erosion, and dynamic sealing performance. Currently, mainstream mortars are mainly divided into three categories: silicate-based mortars, resin-bonded mortars, and pure aluminum powder sealing mortars.

[0003] The above-mentioned sealing mortar has the following problems in actual continuous casting applications:

[0004] Slow setting and delayed hardening: The slag reacts slowly under the alkaline activation of lime, and the initial setting time is too long, which cannot match the fast-paced continuous casting production. This results in the need to wait for hardening after the nozzle is installed, which drags down the operation efficiency.

[0005] Interface weakening: The hydration products at the slag-aggregate interface are loose, making the interface susceptible to erosion by molten steel during high-temperature service. Furthermore, excessive aluminum powder releases hydrogen gas which mixes into the molten steel, causing subsurface bubble defects in the cast billet. Crucially, conventional systems fail to integrate slag activation, micro-expansion phase-controlled generation, and nano-barrier mechanisms, resulting in limited overall sealing performance. Therefore, we propose a sealing mortar for sliding gate nozzles and its preparation method. Summary of the Invention

[0006] The purpose of this invention is to provide a sealing mortar for sliding gate nozzles and its preparation method. By reconstructing the activity activation path and microstructure evolution mechanism of slag-lime-based sealing mortar, a breakthrough in all dimensions from solidification kinetics, high-temperature adaptability to metallurgical safety is achieved.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A sealing mortar for sliding gate nozzles, by weight, comprises 35-45 parts blast furnace slag powder, 15-25 parts fine calcareous quicklime powder, 30-40 parts graded quartz sand aggregate, 8-12 parts pre-activated composite activator, 5-10 parts sodium silicate-based rapid hardening conditioning liquid, 0.5-2 parts plasticizing water-retaining fiber, and 0.1-0.3 parts aluminum powder antioxidant.

[0009] The pre-activated composite activator is prepared by dry blending sodium-based bentonite and anhydrous potassium carbonate at a mass ratio of 7:3.

[0010] The sodium silicate-based rapid hardening conditioning solution has a sodium silicate modulus of 1.5-2.0 and a solid content of ≥40%.

[0011] The plasticizing and water-retaining fiber is a short hydroxyethyl cellulose fiber with a length of 1-3 mm and a degree of substitution of 1.8-2.2. It forms a three-dimensional network structure in the putty, with each gram of fiber having a water-binding capacity ≥15g, reducing the water evaporation rate during the plasticization stage to 0.12g / g. •h; Silane coupling agent grafted onto the fiber surface, with a hydrogen bond density of 8.5× between the fiber and slag particles. bonds / This increases the bending strength of the green billet to 2.8-3.5 MPa.

[0012] Preferably, the blast furnace slag powder is water-quenched and rapidly cooled granulated slag, with a glass content ≥90% and a specific surface area of ​​450-550. / kg, CaO / SiO2 molar ratio 1.0-1.2, and Fe2O3 content ≤1.5wt%; MgO and Al2O3 in the slag powder form a spinel phase, which reacts with calcareous quicklime at >1000℃ to form magnesium aluminum spinel MgAl2O4, compensating for the coefficient of thermal expansion to 4.8× / ℃, reducing the thermal shock crack rate of the mortar.

[0013] Preferably, the fine calcareous quicklime powder has an active CaO content ≥92%, a loss on ignition ≤2%, and a particle size of [missing information]. =5-10μm; the quicklime exists in the form of micron-sized rhombohedral crystals, and its surface pre-adsorbs CO2 to form a nano-calcium carbonate coating layer. During mixing, it preferentially reacts with sodium silicate conditioning liquid to release heat of hydration, causing the system to heat up to 45-50℃ within 60s, thus accelerating the kinetic process of slag deagglomeration.

[0014] Preferably, the graded quartz sand mortar aggregate consists of 40-70 mesh coarse aggregate, 80-120 mesh medium aggregate, and <200 mesh fine powder, wherein the coarse aggregate is fused silica sand with a crystalline phase content ≤5%, and the medium and fine aggregates are crushed natural quartzite sand with a SiO2 purity ≥99.2%; this gradation results in an aggregate bulk density of 1.85-1.92 g / L. .

[0015] Preferably, the cation exchange capacity (CEC) of sodium-based bentonite in the pre-activated composite activator is ≥110 mmol / 100g, and the interlayer spacing is [not specified]. =1.25-1.35nm; anhydrous potassium carbonate particle size <15μm, and dissolves at a rate ≥0.28g / s in sodium silicate solution; a 7:3 ratio of bentonite to potassium carbonate makes... / The molar ratio is stable at 0.4-0.6.

[0016] Preferably, the sodium silicate-based rapid-hardening conditioning liquid has a modulus precisely controlled at 1.8 ± 0.05, a Na₂O content of 14.5-16.0 wt%, and a viscosity of 350-450 mPa·s; its low-polymerization degree silicate ions [SiO₂(OH)₂] are present. 2- With a proportion greater than 65%, it directly penetrates to the slag crushing interface and... The bonds form short-chain CSH gels, which shorten the initial setting time.

[0017] Preferably, the aluminum powder antioxidant is flake-shaped aluminum powder with a flake diameter of 10-25 μm, an aspect ratio of 30-50, and a zirconium phosphate film coating with a thickness of 80-120 nm.

[0018] Aluminum powder releases electrons in an alkaline environment: ;

[0019] The rate of dissolved oxygen consumption is 0.35 mg O2 / (g·min), which keeps the oxygen partial pressure inside the clay ≤0.01 atm, preventing the volume expansion caused by the conversion of Fe2O3 to Fe3O4.

[0020] A method for preparing a sealing putty for sliding gates, the method comprising the following steps:

[0021] S1. Blast furnace slag powder and calcareous quicklime powder are fed into a planetary ball mill under nitrogen protection, and graded quartz sand aggregate is added. The mixture is dry-mixed at 300 r / min for 15 min. Subsequently, a pre-activated composite activator is added, and the mixture is ground at a pressure of 0.8 MPa and a specific surface area controlled at ≥500. Under the condition of / kg, continuous ball milling for 30 minutes was carried out to form a composite powder with an accelerated deagglomeration interface;

[0022] S2. Heat a sodium silicate solution with a modulus of 1.8 ± 0.05 to 45°C, add hydroxyethyl cellulose short fibers, and disperse them at a high speed of 2000 r / min for 10 min to allow the fibers to fully swell and form a three-dimensional network structure. Cool to 25°C for later use.

[0023] S3. Place the composite powder obtained in step S1 into a vacuum kneader, slowly inject the modified sodium silicate conditioning liquid from step S2, and simultaneously add flake-shaped aluminum powder antioxidant and nano magnesium powder; under a vacuum of -0.08MPa and a temperature of 25℃, knead at a low speed of 40r / min for 5min, and then switch to a high speed of 80r / min for 8min.

[0024] S4. During the kneading process, nitrogen gas is continuously introduced to replace residual oxygen. When the system temperature rises to 50°C, stirring is stopped, and the mixture is allowed to stand for 2 minutes to allow the magnesium powder to react fully. A microbubble network is formed; the kneader is restarted to 60 r / min and held for 5 min to orient the hydroxyethyl cellulose fibers along the shear force direction, resulting in a putty with a plasticity index of 0.35-0.45.

[0025] S5. Press the plastic clay into the steel mold and gradually increase the temperature at a rate of 0.5℃ / min:

[0026] Sodium silicate and 60℃ for 1 hour, sodium silicate and Generate short-chain CSH gel;

[0027] The bentonite layers were kept at 120℃ for 2 hours to remove interlayer water and form nanosheets.

[0028] The aluminum powder oxidation was completed after holding at 300℃ for 30 minutes, with a residual porosity of <5%.

[0029] S6. Under a nitrogen atmosphere, heat the material to 800°C at a rate of 10°C / min to trigger the solid-phase reaction. Then, cool the material to 150°C and immerse it in silica sol. Vacuum permeate for 10 minutes, then dry it at 80°C until the moisture content is ≤0.5wt%. Seal it in an aluminum-plastic composite bag with a humidity of less than 10%.

[0030] Preferably, the solid-phase reaction is triggered by heating to 800°C at a rate of 10°C / min under a nitrogen atmosphere, and the reaction formula is as follows: ;

[0031] (ΔV+8.2%)

[0032] Maintaining a constant temperature for 30 minutes stabilizes the expansion rate, enabling the construction of a dynamic gap compensation layer.

[0033] The technical effects and advantages of this invention are as follows:

[0034] By using a pre-activated composite activator to synergistically modify the slag, the mortar forms a dense reaction interface during the plastic stage, overcoming the lag defect of the traditional slag-lime system. From initial setting and hardening to high-temperature service, the system maintains dynamic adhesion to the sliding nozzle: during the initial setting stage, oligomeric silicates rapidly penetrate the slag interface to generate a rigid gel skeleton, achieving rapid structural locking and significantly shortening the nozzle installation waiting time; during the high-temperature stage, the aggregate and activator trigger precise phase transformation expansion, dynamically compensating for thermal shrinkage gaps and completely eliminating steel penetration channels; during long-term service, the bottom layer of the gradient sealing layer forms a porous buffer structure, absorbing mechanical vibration stress and preventing brittle peeling of the interface.

[0035] A dual oxygen consumption mechanism is introduced. Flake aluminum powder consumes dissolved oxygen to inhibit the valence state change of iron oxides and avoid uncontrolled expansion; nano-magnesium powder generates an inert hydrogen microbubble network, which not only blocks heat conduction but also builds a physical barrier inside the mortar to prevent hydrogen from escaping into the molten steel. At the same time, the calcium components in the slag capture sulfur elements in the molten steel to form a stable sulfide layer, eliminating subsurface bubble defects in the billet from the source.

[0036] The micro-nano gradient structure design gives the mortar cross-temperature adaptability: the surface calcium aluminum feldspar continuous phase resists the erosion of molten steel; the transition layer hydration gel fiber network relieves stress concentration; and the bottom porous slag buffers thermal shock deformation. This structure allows the mortar to remain intact during repeated hot and cold cycles, significantly reducing the frequency of nozzle replacement. Detailed Implementation

[0037] 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. The specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. 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.

[0038] This invention proposes a sealing mortar for sliding gate nozzles and its preparation method. The sealing mortar for sliding gate nozzles is composed of blast furnace slag powder, calcareous quicklime powder, graded quartz sand aggregate, pre-activated composite activator, sodium silicate-based rapid hardening conditioning liquid, plasticizing water-retaining fiber, and aluminum powder antioxidant.

[0039] It should be noted that the pre-activated composite activator is made by dry blending sodium-based bentonite and anhydrous potassium carbonate at a mass ratio of 7:3.

[0040] The sodium silicate-based rapid hardening conditioning solution has a sodium silicate modulus of 1.5-2.0 and a solid content of ≥40%.

[0041] The plasticizing and water-retaining fiber is made of hydroxyethyl cellulose short fibers with a length of 1-3 mm and a degree of substitution of 1.8-2.2. It forms a three-dimensional network structure in the putty, and each gram of fiber has a water-binding capacity of ≥15g, reducing the water evaporation rate during the plasticization stage to 0.12g / g. •h; Silane coupling agent grafted onto the fiber surface, with a hydrogen bond density of 8.5× between the fiber and slag particles. bonds / This increases the bending strength of the green billet to 2.8-3.5 MPa.

[0042] Blast furnace slag powder is water-quenched and rapidly cooled granulated slag with a glass content ≥90% and a specific surface area of ​​450-550. / kg, CaO / SiO2 molar ratio 1.0-1.2, and Fe2O3 content ≤1.5wt%; MgO and Al2O3 in the slag powder form a spinel phase, which reacts with calcareous quicklime at >1000℃ to form magnesium aluminum spinel MgAl2O4, compensating for the coefficient of thermal expansion to 4.8× / ℃, reducing the thermal shock crack rate of the mortar;

[0043] The active CaO content in the fine powder of calcareous quicklime is ≥92%, the loss on ignition is ≤2%, and the particle size is... =5-10μm; quicklime exists in the form of micron-sized rhombohedral crystals, and its surface pre-adsorbs CO2 to form a nano-calcium carbonate coating layer. During mixing, it preferentially reacts with sodium silicate conditioning liquid to release heat of hydration, causing the system to heat up to 45-50℃ within 60s, thus accelerating the deagglomeration kinetics of slag.

[0044] The graded quartz sand mortar aggregate consists of 40-70 mesh coarse aggregate, 80-120 mesh medium aggregate, and <200 mesh fine powder. The coarse aggregate is fused silica sand with a crystalline phase content ≤5%, while the medium and fine aggregates are crushed natural quartzite sand with a SiO2 purity ≥99.2%. This gradation results in an aggregate bulk density of 1.85-1.92 g / L. ;

[0045] The cation exchange capacity (CEC) of sodium-based bentonite in the pre-activated composite activator is ≥110 mmol / 100 g, and the interlayer spacing is [not specified]. =1.25-1.35nm; anhydrous potassium carbonate particle size <15μm, and dissolves at a rate ≥0.28g / s in sodium silicate solution; a 7:3 ratio of bentonite to potassium carbonate makes... / The molar ratio is stable at 0.4-0.6;

[0046] The modulus of the sodium silicate-based rapid-hardening conditioning solution is precisely controlled at 1.8±0.05, the Na2O content is 14.5-16.0wt%, and the viscosity is 350-450mPa·s; its low-polymerization degree silicate ion [SiO2(OH)2]... 2- With a proportion greater than 65%, it directly penetrates to the slag crushing interface and... Bonding forms short-chain CSH gels, shortening the initial setting time;

[0047] The aluminum powder antioxidant is flake-shaped aluminum powder with a diameter of 10-25μm and an aspect ratio of 30-50. The surface is coated with a zirconium phosphate film with a thickness of 80-120nm.

[0048] Aluminum powder releases electrons in an alkaline environment: ;

[0049] The rate of dissolved oxygen consumption is 0.35 mg O2 / (g·min), which keeps the oxygen partial pressure inside the clay ≤0.01 atm and prevents the volume expansion caused by the conversion of Fe2O3 to Fe3O4.

[0050] As an option, aluminum powder antioxidants are synergistically added to nano-magnesium powder (particle size 100-300nm, accounting for 30% of the aluminum powder mass). The magnesium powder triggers a reaction at 60-80℃: Mg+2H2O→Mg(OH)2+H2↑. The generated hydrogen gas forms a microbubble network in the mortar, which reduces the thermal conductivity at high temperature (>1000℃) to 0.8-1.0W / (m·K), reducing the heat loss of molten steel by more than 18%.

[0051] Under the scouring of molten steel at 1300℃, the medium-graded quartz sand in the mortar undergoes a solid-phase reaction with calcareous quicklime: (Pseudo-wollastonite) ΔV expansion +12.7%;

[0052] (Amber) ΔV expansion +8.2%;

[0053] The expansion dynamically fills the sliding gap, and after compensating for shrinkage, it still maintains a net expansion rate of 0.8-1.2%, with a sealing pressure ≥0.35MPa;

[0054] Based on the ion penetration effect of the pre-activated composite activator, the slag reaction rate of the mortar reaches 82-85% within 24 hours, generating nanorod-shaped CSH (50-200 nm in length and 5-10 nm in diameter) and plate-shaped hydrated calcium aluminate (C4AH). 13 (with a sheet diameter of 0.2-0.5μm), the two form a rigid skeleton + flexible filler structure, enabling the room temperature compressive strength to reach 45-50MPa within 48h;

[0055] The impermeability mechanism of the mortar relies on the nanosheet structure formed by the dehydration of sodium-based bentonite at 600-800℃, with a sheet spacing of 0.7-0.9 nm, and a rejection rate of ≥99.5% for Fe and Mn ions; simultaneously, the ore dissolved from the slag... It combines with molten steel [S] to form a dense CaS layer (10-20 μm thick), which reduces the molten steel penetration rate from 0.22 mL / min to 0.03 mL / min.

[0056] Based on the above, the preparation method of the sealing putty for sliding gates is as follows:

[0057] S1. Blast furnace slag powder and calcareous quicklime powder are fed into a planetary ball mill under nitrogen protection, and graded quartz sand aggregate is added. The mixture is dry-mixed at 300 r / min for 15 min. Subsequently, a pre-activated composite activator is added, and the mixture is ground at a pressure of 0.8 MPa and a specific surface area controlled at ≥500. Under the condition of / kg, continuous ball milling for 30 minutes was carried out to form a composite powder with an accelerated deagglomeration interface;

[0058] S2. Heat a sodium silicate solution with a modulus of 1.8 ± 0.05 to 45°C, add hydroxyethyl cellulose short fibers, and disperse them at a high speed of 2000 r / min for 10 min to allow the fibers to fully swell and form a three-dimensional network structure. Cool to 25°C for later use.

[0059] S3. Place the composite powder obtained in step S1 into a vacuum kneader, slowly inject the modified sodium silicate conditioning liquid from step S2, and simultaneously add flake-shaped aluminum powder antioxidant and nano magnesium powder; under a vacuum of -0.08MPa and a temperature of 25℃, knead at a low speed of 40r / min for 5min, and then switch to a high speed of 80r / min for 8min.

[0060] S4. During the kneading process, nitrogen gas is continuously introduced to replace residual oxygen. When the system temperature rises to 50°C, stirring is stopped, and the mixture is allowed to stand for 2 minutes to allow the magnesium powder to react fully. A microbubble network is formed; the kneader is restarted to 60 r / min and held for 5 min to orient the hydroxyethyl cellulose fibers along the shear force direction, resulting in a putty with a plasticity index of 0.35-0.45.

[0061] S5. Press the plastic clay into the steel mold and gradually increase the temperature at a rate of 0.5℃ / min:

[0062] Sodium silicate and 60℃ for 1 hour, sodium silicate and Generate short-chain CSH gel;

[0063] The bentonite layers were kept at 120℃ for 2 hours to remove interlayer water and form nanosheets.

[0064] The aluminum powder oxidation was completed after holding at 300℃ for 30 minutes, with a residual porosity of <5%.

[0065] S6. Under a nitrogen atmosphere, heat the material to 800°C at a rate of 10°C / min to trigger the solid-phase reaction. Then, cool the material to 150°C and immerse it in silica sol. Vacuum permeate for 10 minutes, then dry it at 80°C until the moisture content is ≤0.5wt%. Seal it in an aluminum-plastic composite bag with a humidity of less than 10%.

[0066] Example 1

[0067] The formula for the sealing mortar for the sliding gate is composed of 40 parts slag powder, 20 parts quicklime, 36 parts quartz aggregate, 9 parts pre-activation activator, 6 parts sodium silicate quick-hardening liquid, 0.8 parts cellulose fiber, and 0.2 parts aluminum powder antioxidant.

[0068] Based on the above, the preparation method has the following parameter adjustments:

[0069] Dry-mix pre-activation: Place slag powder, quicklime, and pre-activation activator in a high-speed mixer and mix at 1200 r / min for 5 min. The activator coats the slag particles.

[0070] Wet pulping: Inject sodium silicate quick-hardening liquid and fiber, switch to 800r / min and stir to form a thick paste;

[0071] Aggregate strengthening: Add quartz aggregate in batches and knead at a low speed of 300r / min until the aggregate is evenly coated with slurry;

[0072] Final mixing of aluminum powder: Just before construction, add aluminum powder antioxidant and mix by hand for 30 seconds to ensure thorough mixing in the absence of air.

[0073] The sealing putty for sliding gates prepared in this embodiment has the following characteristics:

[0074] Rapid shaping in 5 minutes; sodium silicate gel quickly forms a web between aggregates, supporting lock-on installation at the sprue.

[0075] Zero thermal shock penetration; synergistic effect of aluminum powder oxidation expansion and quartz phase transformation to compensate for 0.15mm shrinkage gap at 1600℃.

[0076] Interfacial hydrogen control: The fiber network captures microbubbles from the aluminum reaction, resulting in no hydrogen enrichment at the molten steel interface.

[0077] Example 2

[0078] The difference from Example 1 is that the formula of the sealing putty for the sliding gate is composed of 42 parts slag powder, 15 parts quicklime, 33 parts quartz aggregate, 11 parts pre-activation activator, 8 parts sodium silicate quick-hardening liquid, 1.5 parts cellulose fiber, and 0.25 parts aluminum powder antioxidant.

[0079] Based on the above, the preparation method has the following parameter adjustments:

[0080] Deep activation of slag involves mixing a pre-activation activator with 50% sodium silicate rapid hardening liquid, spraying it onto the slag powder, and then sealing and aging it for 24 hours.

[0081] Lime slow-release treatment: quicklime and the remaining sodium silicate solution are mixed to form lime milk, and then allowed to stand for 2 hours for slaking.

[0082] Gradient compounding: aged slag, lime milk, and quartz aggregate are added sequentially to a planetary mixer and kneaded under vacuum at 200 rpm for 10 minutes.

[0083] The fibers are oriented and dispersed by sprinkling in aluminum silicate fibers and aluminum powder, and the vibrating screen promotes the axial arrangement of the fibers.

[0084] The sealing putty for sliding gates prepared in this embodiment has the following characteristics:

[0085] The expansion is intelligently adapted, forming nano-sized ettringite seed crystals in aged slag, triggering step expansion at high temperature (600℃ kyanite phase transformation → 1200℃ calcium aluminum feldspar transformation).

[0086] It is corrosion resistant, with axial fibers blocking the seepage of molten steel, and the erosion depth at the mortar interface after continuous casting is <0.3mm;

[0087] Long-lasting cushioning; vibration-dispersing fibers form a spring layer at the interface, and it has not cracked after 28 thermal shock cycles.

[0088] Example 3

[0089] The difference from Examples 1-2 is that the formula of the sealing mortar for the sliding gate is composed of 38 parts slag powder, 22 parts quicklime, 40 parts quartz aggregate, 10 parts pre-activation activator, 5 parts sodium silicate rapid hardening liquid, 1.8 parts composite fiber (polypropylene + basalt), 0.1 parts aluminum powder antioxidant + 0.05 parts nano MgO;

[0090] The preparation parameters are as follows:

[0091] Pre-wetting of aggregate: 70% of quartz aggregate is immersed in sodium silicate rapid hardening liquid and ultrasonically treated for 10 minutes to form a hydrophobic film.

[0092] Slag-lime nucleus reaction: Slag powder, quicklime, and pre-activation activator are dry-mixed and then pressed into thin sheet blanks;

[0093] Double-layer composite construction:

[0094] The bottom layer consists of a mixture of moistened aggregate, crushed green body particles, and 60% fiber, compacted together.

[0095] For the surface layer, the remaining raw materials are mixed with nano-MgO at high speed to form a flexible paste, which is then applied and covered.

[0096] Steam curing: Curing in saturated steam at 40℃ for 6 hours to activate interfacial bonding.

[0097] The sealing putty for sliding gates prepared in this embodiment has the following characteristics:

[0098] The interfacial toughness is greatly improved, the hydrophobic film of the aggregate is interlocked with the green body particles, and the shear strength is increased by 300%;

[0099] Hydrogen and oxygen dual barriers are used, with the surface layer of nano-MgO preferentially consuming oxygen, and the expansion rate of aluminum powder is stably controlled within ±1%;

[0100] Anti-delamination protection: Fibers grow across layers to form a root structure, preventing interlayer delamination caused by molten steel intrusion.

[0101] The three sets of examples demonstrate innovative adjustments to the component interaction modes through process innovation: Example 1 uses a rapid gelation network as its core to meet the immediate needs of the production line; Example 2 leverages the intelligent expansion characteristics released by deep activation of slag to adapt to long-cycle operating conditions; Example 3 creates an interface-level enhanced configuration to overcome the sealing challenges of high-density steel grades. The same formulation system can be specifically enhanced in terms of performance through process empowerment, proving the high adaptability of the core technology.

[0102] The performance indicators of the three embodiments of the present invention are compared as follows:

[0103] Performance Indicator Comparison Table

[0104]

[0105] Table 1

[0106] In summary, this invention, through the synergistic modification of slag by a pre-activated composite activator, enables the mortar to form a dense reaction interface during the plastic stage, overcoming the lag defect of the traditional slag-lime system. From initial setting and hardening to high-temperature service, the system maintains dynamic adhesion to the sliding nozzle: during the initial setting stage, oligomeric silicates rapidly penetrate the slag interface, generating a rigid gel skeleton, achieving rapid structural locking and significantly shortening the nozzle installation waiting time; during the high-temperature stage, the aggregate and activator trigger precise phase transformation expansion, dynamically compensating for thermal shrinkage gaps and completely eliminating steel penetration channels; during long-term service, the bottom layer of the gradient sealing layer forms a porous buffer structure, absorbing mechanical vibration stress and preventing brittle peeling of the interface.

[0107] A dual oxygen consumption mechanism is introduced. Flake aluminum powder consumes dissolved oxygen to inhibit the valence state change of iron oxides and avoid uncontrolled expansion; nano-magnesium powder generates an inert hydrogen microbubble network, which not only blocks heat conduction but also builds a physical barrier inside the mortar to prevent hydrogen from escaping into the molten steel. At the same time, the calcium components in the slag capture sulfur elements in the molten steel to form a stable sulfide layer, eliminating subsurface bubble defects in the billet from the source.

[0108] The micro-nano gradient structure design gives the mortar cross-temperature adaptability: the surface calcium aluminum feldspar continuous phase resists the erosion of molten steel; the transition layer hydration gel fiber network relieves stress concentration; and the bottom porous slag buffers thermal shock deformation. This structure allows the mortar to remain intact during repeated hot and cold cycles, significantly reducing the frequency of nozzle replacement.

[0109] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sealing putty for sliding gate nozzles, characterized in that, The formula for the sealing mortar for the sliding gate, by weight, consists of 35-45 parts blast furnace slag powder, 15-25 parts fine calcareous quicklime powder, 30-40 parts graded quartz sand aggregate, 8-12 parts pre-activated composite activator, 5-10 parts sodium silicate-based rapid hardening conditioning liquid, 0.5-2 parts plasticizing water-retaining fiber, and 0.1-0.3 parts aluminum powder antioxidant. The pre-activated composite activator is prepared by dry blending sodium-based bentonite and anhydrous potassium carbonate at a mass ratio of 7:

3. The sodium silicate-based rapid hardening conditioning solution has a sodium silicate modulus of 1.5-2.0 and a solid content of ≥40%. The plasticizing and water-retaining fiber is made of hydroxyethyl cellulose short fibers with a length of 1-3 mm and a degree of substitution of 1.8-2.

2. It forms a three-dimensional network structure in the putty, and each gram of fiber has a water-binding capacity of ≥15g, reducing the water evaporation rate during the plasticization stage to 0.12g / •h; Silane coupling agent grafted onto the fiber surface, with a hydrogen bond density of 8.5× between the fiber and slag particles. bonds / This increases the bending strength of the green billet to 2.8-3.5 MPa. The aluminum powder antioxidant is flake-shaped aluminum powder with a flake diameter of 10-25μm, an aspect ratio of 30-50, and a surface coated with a zirconium phosphate film with a thickness of 80-120nm. Aluminum powder releases electrons in an alkaline environment: ; The rate of dissolved oxygen consumption is 0.35 mg O2 / (g·min), which keeps the oxygen partial pressure inside the clay ≤0.01 atm, preventing the volume expansion caused by the conversion of Fe2O3 to Fe3O4.

2. The sealing putty for sliding gates according to claim 1, characterized in that, The blast furnace slag powder is water-quenched and rapidly cooled granulated slag, with a glass content ≥90% and a specific surface area of ​​450-550. / kg, CaO / SiO2 molar ratio 1.0-1.2, and Fe2O3 content ≤1.5wt%; MgO and Al2O3 in the slag powder form a spinel phase, which reacts with calcareous quicklime at >1000℃ to form magnesium aluminum spinel MgAl2O4, compensating for the coefficient of thermal expansion to 4.8× / ℃, reducing the thermal shock crack rate of the mortar.

3. The sealing putty for sliding gates according to claim 1, characterized in that, The fine calcareous quicklime powder contains ≥92% active CaO, ≤2% loss on ignition, and has a particle size of [missing information]. =5-10μm; the quicklime exists in the form of micron-sized rhombohedral crystals, and its surface pre-adsorbs CO2 to form a nano-calcium carbonate coating layer. During mixing, it preferentially reacts with sodium silicate conditioning liquid to release heat of hydration, causing the system to heat up to 45-50℃ within 60s, thus accelerating the kinetic process of slag deagglomeration.

4. The sealing putty for sliding gates according to claim 1, characterized in that, The graded quartz sand mortar aggregate consists of 40-70 mesh coarse aggregate, 80-120 mesh medium aggregate and <200 mesh fine powder, wherein the coarse aggregate is fused quartz sand with a crystalline phase content of ≤5%, and the medium and fine aggregates are natural quartzite crushed sand with a SiO2 purity of ≥99.2%.

5. The sealing putty for sliding gates according to claim 1, characterized in that, The cation exchange capacity (CEC) of sodium-based bentonite in the pre-activated composite activator is ≥110 mmol / 100g, and the interlayer spacing is... =1.25-1.35nm; anhydrous potassium carbonate particle size <15μm, and dissolves at a rate ≥0.28g / s in sodium silicate solution; a 7:3 ratio of bentonite to potassium carbonate makes... / The molar ratio is stable at 0.4-0.

6.

6. The sealing putty for sliding gates according to claim 1, characterized in that, The modulus of the sodium silicate-based rapid hardening conditioning liquid is precisely controlled at 1.8±0.05, the Na2O content is 14.5-16.0wt%, and the viscosity is 350-450mPa·s.

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