阅读说明：本技术 一种快干型空心球隔热耐火浇注料 (Quick-drying hollow sphere heat-insulation refractory castable ) 是由 罗巍 刘义滔 欧阳德刚 何金平 朱善合 丁翠娇 汪峰 刘刚峰 于 2021-09-15 设计创作，主要内容包括：本发明公开了一种快干型空心球隔热耐火浇注料,包括如下重量百分比的原料：氧化铝空心球35～45％,微孔六铝酸钙轻质骨料5～8％,漂珠3～5％,纳米二氧化硅气凝胶粉3～5％,蓝晶石粉5～8％,一级高铝熟料粉5～8％,耐火纤维10～15％,六钛酸钾晶须2～3％,硅微粉2～4％,α-Al-(2)O-(3)微粉10～15％,复合减水剂0.1～0.3％,水性硅聚醚消泡剂0.02～0.05％,促凝剂0.1～0.3％,缓凝剂0.05～0.15％；另外,还包括硅溶胶,以外加的形式加入,加入量占其他原料总质量的20～30％。该耐火浇注料具有养护和烘干时间短、隔热性能与抗热震稳定性优良、力学性能好等优点,不仅能够有效地降低薄板坯连铸连轧隧道式加热炉高温水冷炉辊的水冷热损失、提高加热炉热效率、延长炉辊隔热层使用寿命,还减少了炉辊的烘干时间、缩短了制作周期。(The invention discloses a quick-drying hollow sphere heat-insulating refractory castable which comprises the following raw materials in percentage by weight: 35-45% of alumina hollow spheres, 5-8% of microporous calcium hexaluminate lightweight aggregate, 3-5% of floating beads, 3-5% of nano silica aerogel powder, 5-8% of kyanite powder, 5-8% of first-grade high alumina clinker powder, 10-15% of refractory fibers, 2-3% of potassium hexatitanate whiskers, 2-4% of silica micropowder, alpha-Al 2 O 3 10-15% of micro powder, 0.1-0.3% of composite water reducing agent, 0.02-0.05% of water-based silicon polyether defoaming agent, 0.1-0.3% of coagulant and 0.05-0.15% of retarder; in addition, the silicon sol is added in an additional mode, and the adding amount accounts for 20-30% of the total mass of other raw materials. The refractory castable has the advantages of short curing and drying time, excellent heat-insulating property and thermal shock resistance, good mechanical property and the like,the method not only can effectively reduce the water-cooling heat loss of the high-temperature water-cooling furnace roller of the tunnel type heating furnace for continuously casting and rolling the sheet billet, improve the heat efficiency of the heating furnace, prolong the service life of a heat-insulating layer of the furnace roller, but also reduce the drying time of the furnace roller and shorten the manufacturing period.)

1. A quick-drying hollow sphere heat-insulation refractory castable is characterized by comprising the following raw materials in percentage by weight: 35-45% of alumina hollow spheres, 5-8% of microporous calcium hexaluminate lightweight aggregate, 3-5% of floating beads, 3-5% of nano silica aerogel powder, 5-8% of kyanite powder, 5-8% of first-grade high alumina clinker powder, 10-15% of refractory fibers, 2-3% of potassium hexatitanate whiskers, 2-4% of silica micropowder, alpha-Al₂O₃10-15% of micro powder, 0.1-0.3% of composite water reducing agent, 0.02-0.05% of water-based silicon polyether defoaming agent, 0.1-0.3% of coagulant and 0.05-0.15% of retarder; in addition, the silicon sol is added in an additional mode, and the adding amount accounts for 20-30% of the total mass of other raw materials.

2. The quick-drying hollow sphere heat-insulating refractory castable according to claim 1, wherein the alumina hollow sphere is particle graded, and specifically comprises: 10-15% by weight of alumina hollow spheres with the particle size of less than or equal to 5mm and less than 3mm, 10-18% by weight of alumina hollow spheres with the particle size of less than or equal to 3mm and less than 1mm, and 8-15% by weight of alumina hollow spheres with the particle size of less than or equal to 1mm and less than 0.2 mm.

3. The quick-drying hollow sphere heat-insulating refractory castable according to claim 1, wherein the particle size of the microporous calcium hexaluminate lightweight aggregate is 2-3 mm, and the average pore diameter of micropores is less than or equal to 6 μm.

4. The quick-drying hollow sphere heat-insulating refractory castable according to claim 1, wherein the floating beads have a particle size of 80-200 meshes; the granularity of the cyanite powder is 80-120 meshes; the granularity of the first-grade high-aluminum clinker powder is less than or equal to 200 meshes.

5. The quick-drying hollow sphere heat-insulating refractory castable according to claim 1, wherein the density of the nano silica aerogel powder is less than or equal to 0.05g/cm³The specific surface area is more than or equal to 600m²/g。

6. The quick-drying hollow sphere heat-insulating refractory castable according to claim 1, wherein the refractory fiber is prepared from waste refractory fiber after being used in a metallurgical furnace, and specifically, the recovered waste zirconium-containing refractory fiber or aluminum silicate refractory fiber is sheared into short fiber with the diameter of 5-10 mm, and the short fiber is sprayed on the surface of the refractory fiber by using polyethylene glycol aqueous solution with the concentration of 0.7-0.8 g/100mL for modification treatment.

7. The quick-drying hollow sphere heat-insulating refractory castable according to claim 1, wherein the potassium hexatitanate whisker has a diameter of 2-4 μm and a length-diameter ratio of 10-20.

8. The quick-drying hollow sphere heat-insulating refractory castable according to claim 1, wherein the silica micropowder is active silica micropowder with a particle size of less than or equal to 500 meshes, and the alpha-Al is₂O₃The granularity of the micro powder is less than or equal to 500 meshes; the silicon solutionSiO in glue₂The content is 30-40%, and the pH value is 9.0-9.5.

9. The quick-drying hollow sphere heat-insulating refractory castable according to claim 1, characterized in that the compound water reducing agent is a mixture of an FS10 high-efficiency water reducing agent and sodium tripolyphosphate, wherein the FS10 high-efficiency water reducing agent accounts for 75-90% of the total mass of the compound water reducing agent, and the sodium tripolyphosphate accounts for 10-25% of the total mass of the compound water reducing agent.

10. The quick-drying hollow sphere heat-insulating refractory castable according to claim 1, wherein the coagulant is sintered magnesia powder, the MgO content is not less than 98%, and the particle size is not more than 300 meshes; the retarder is citric acid.

Technical Field

The invention relates to the technical field of refractory materials, in particular to a quick-drying hollow sphere heat-insulating refractory castable for a high-temperature water-cooling furnace roller of a tunnel heating furnace.

Background

The tunnel type heating furnace for continuous casting and rolling of the sheet billet has the characteristics of long furnace body and large number of furnace rollers, the high-temperature water-cooled furnace rollers are used for supporting and driving the sheet billet in the furnace, the temperature in the furnace is generally as high as 1100-1300 ℃, in order to improve the strength and rigidity of the furnace rollers, a fireproof heat-insulation protective layer is usually adopted between metal roller rings, water is introduced into the furnace rollers for cooling, and the functions of protecting the furnace rollers, reducing the heat loss of water cooling and prolonging the service life are achieved.

The furnace roller fire-resistant heat-insulating protective layer mainly comprises a fire-resistant castable and a fire-resistant fiber material, wherein a single fire-resistant fiber material is relatively rare in practical application due to the deterioration of high-temperature performance and short service life, and the most applied fire-resistant castable heat-insulating protective layer is currently used. For example, a chinese patent with an authorization publication number CN100408515C discloses a refractory castable for a roller hearth furnace roller, which is prepared from the following components in parts by weight: electrofused mullite (granularity less than or equal to 3 mm): 20-45%, flint clay (granularity l-5 mm): 0-30%, mullite (particle size 200 mesh): 10-20%, cordierite (particle size less than or equal to 5 mm): 10-25%, kyanite (particle size 180 mesh): 5-10%, silicon oxide micro powder (the granularity is less than or equal to 5 mu m): 2-3%, alumina micropowder (granularity is less than or equal to 5 μm): 5-8%, high alumina cement: 4-5%, stainless steel fiber: 2-4%, explosion-proof fiber: 0.1-0.15%, sodium tripolyphosphate: 0.15-0.3%, water: 7.5 to 10 percent. The patent improves the cracking and falling effects of the casting material layer to a certain extent, prolongs the service life of the furnace roller, and still has the defects of higher heat conductivity coefficient and poor heat insulation performance.

The Chinese patent application with publication number CN101792294A discloses a light heat-insulating refractory castable, which comprises the following components in percentage by weight: chemically modified lightweight aggregate: 40-60%; electrofused mullite (0-1 mm): 10-20%; cyanite powder (particle size 180 mesh): 5-10%; first-grade bauxite chamotte powder (granularity 180 meshes): 5-10%; silicon dioxide micropowder (particle size less than or equal to 5 μm): 3-8%; alpha-Al₂O₃Micro powder (granularity is less than or equal to 5 mu m): 3-8%; high-alumina cement: 5-10%; zirconium-containing high-alumina refractory fiber: 0.5-10%; heat-resistant steel fiber: 1.5-4%; melamine: 0.1-1%; organic explosion-proof fiber: 0.05 to 0.10 percent. The application of the patent reduces the heat conductivity coefficient of the castable by adopting the lightweight aggregate, and remarkably improves the mechanical property and the service life of the lightweight castable by chemically improving the lightweight aggregate, but similar to the previous patent, because the steel fiber is adopted as a reinforcing and toughening mode, the steel fiber is easy to generate high-temperature oxidation expansion and embrittlement failure in the high-temperature use process, and the high-temperature service performance of the castable is degraded by the high-temperature reaction of an oxidation product and the refractory castable.

In order to overcome the defects, the Chinese patent with the authorization publication number CN102161593B discloses a light refractory castable for a CSP furnace roller heat insulation lining, which adopts refractory fibers to replace steel fibers to play a role in strengthening and toughening, and comprises the following components in percentage by weight: light mullite aggregate: 40-50%; flint clay (granularity 0.1-1 mm): 5-8%; cyanite powder (granularity 60-120 meshes): 5-7%; first-grade bauxite chamotte powder (the granularity is less than or equal to 180 meshes): 6-9%; silicon micropowder: 7-9%; alpha-Al₂O₃Micro-powder: 5-8%; high-alumina cement: 10-18%; refractory fiber: 1-4%; spodumene (particle size 160-200 mesh): 1-1.5%; sodium hexametaphosphate: 0.05-0.154%; organic water reducing agent: 0.05-0.15%: 0.04-0.07% of organosilane coupling agent; defoaming agent: 0.03 to 0.06 percent. Compared with the heavy castable in the Chinese patent with the grant publication number CN100408515C, the castable has the characteristics of light volume weight, good mechanical property and excellent thermal shock stability, but because the light mullite aggregate is transported and carriedThe aggregate is easy to break in the transportation process, the deterioration of the aggregate performance not only causes the increase of consumption, but also causes the fluctuation of the mechanical property of the castable, and in addition, the heat insulation performance of the castable still needs to be further improved. In addition, the furnace roller refractory castable needs to be baked for a long time or dried in the normal temperature environment for one month after being poured, maintained and molded, so that the manufacturing time is long, and the document is "perfect"; liu national Wei; development and application of baking-free castable in center of thin slab furnace roller [ J]The roll castable reported in Industrial furnace 2006, 28(2):42-43, 52 ", is used directly in the furnace without baking, but has a density of 2.3g/cm³The mullite heavy castable has poor heat insulation performance, has the problem of cracking and breakage in the use process, and has the service life of more than 10 months.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a quick-drying hollow sphere heat-insulating refractory castable material aiming at the defects in the prior art, which has the advantages of short maintenance and drying time, excellent heat-insulating property and thermal shock resistance, good mechanical property and the like, and not only can effectively reduce the water-cooling heat loss of a high-temperature water-cooling furnace roller of a sheet billet continuous casting and rolling tunnel type heating furnace, improve the heat efficiency of the heating furnace, prolong the service life of a heat-insulating layer of the furnace roller, but also can reduce the drying time of the furnace roller and shorten the manufacturing period.

The technical scheme adopted by the invention for solving the problems is as follows:

a quick-drying hollow sphere heat-insulation refractory castable comprises the following raw materials in percentage by weight: 35-45% of alumina hollow spheres, 5-8% of microporous calcium hexaluminate lightweight aggregate, 3-5% of floating beads, 3-5% of nano silica aerogel powder, 5-8% of kyanite powder, 5-8% of first-grade high alumina clinker powder, 10-15% of refractory fibers, 2-3% of potassium hexatitanate whiskers, 2-4% of silica micropowder, alpha-Al₂O₃10-15% of micro powder, 0.1-0.3% of composite water reducing agent, 0.02-0.05% of water-based silicon polyether defoaming agent, 0.1-0.3% of coagulant and 0.05-0.15% of retarder; in addition, the additive also comprises silica sol which is added in an additional form, and the adding amount accounts for 20-30% of the total mass of other raw materials。

As an improvement of the above technical solution, the alumina hollow sphere is particle-graded, specifically comprising: 10-15 wt% of alumina hollow spheres with the particle size of less than or equal to 5mm and less than 3mm, 10-18 wt% of alumina hollow spheres with the particle size of less than or equal to 3mm and less than 1mm, and 8-15 wt% of alumina hollow spheres with the particle size of less than or equal to 1mm and less than 0.2mm, wherein the sum of the weight percentages of the three alumina hollow spheres with the particle grading is 35-45%, and the alumina hollow spheres are required in the raw materials.

As an improvement of the technical scheme, the particle size of the microporous calcium hexaluminate lightweight aggregate is 2-3 mm, and the average pore diameter of micropores is less than or equal to 6 microns.

As an improvement of the technical scheme, the particle size of the floating beads is 80-200 meshes.

As an improvement of the technical scheme, the density of the nano-silica aerogel powder is less than or equal to 0.05g/cm³The specific surface area is more than or equal to 600m²/g。

As an improvement of the technical scheme, the granularity of the cyanite powder is 80-120 meshes.

As an improvement of the technical scheme, the granularity of the first-grade high-aluminum clinker powder is less than or equal to 200 meshes. The high-aluminum clinker powder is classified according to the content of alumina, and the first-grade high-aluminum clinker powder refers to the high-aluminum clinker powder with the content of alumina more than 80%.

As an improvement of the technical scheme, the refractory fiber is prepared from waste refractory fiber used by a metallurgical furnace, and specifically, the recovered waste zirconium-containing refractory fiber or aluminum silicate refractory fiber is cut into short fibers of 5-10 mm, and the short fibers are sprayed on the surface of the refractory fiber by using a polyethylene glycol aqueous solution with the concentration of 0.7-0.8 g/100mL for modification treatment.

As an improvement of the technical scheme, the potassium hexatitanate whisker has the diameter of 2-4 mu m and the length-diameter ratio of 10-20.

As an improvement of the technical scheme, the silicon micro powder is active silicon micro powder, the granularity is less than or equal to 500 meshes, and the alpha-Al₂O₃The granularity of the micro powder is less than or equal to 500 meshes.

As an improvement of the technical scheme, the composite water reducing agent is a mixture of an FS10 high-efficiency water reducing agent and sodium tripolyphosphate, wherein the FS10 high-efficiency water reducing agent accounts for 75-90% of the total mass of the composite water reducing agent, and the sodium tripolyphosphate accounts for 10-25% of the total mass of the composite water reducing agent.

As an improvement of the technical scheme, the water-based silicon polyether defoaming agent is a commercially available RK-720F silicon polyether defoaming agent.

As an improvement of the technical scheme, the coagulant is sintered magnesia powder, the MgO content is more than or equal to 98 percent, and the granularity is less than or equal to 300 meshes.

As an improvement of the technical scheme, the retarder is citric acid.

As an improvement of the technical proposal, SiO in the silica sol₂The content is 30-40%, and the pH value is 9.0-9.5.

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

through the combined use of the alumina hollow spheres and the floating beads with different aggregate grading, the microstructures of hollow spherical closed air holes with different scales existing in the alumina hollow spheres and the floating beads are utilized, the number of millimeter-level and micron-level closed air holes in the castable is increased, the heat insulation performance and the thermal shock resistance of the castable are improved, and the aims of enhancing the heat insulation protection of the furnace roller, reducing the water cooling heat loss, reducing the volume density and reducing the weight of the furnace roller and the consumption of the rotating power are fulfilled.

By using the 2-3 mm microporous calcium hexaluminate lightweight aggregate and utilizing the characteristics of the aggregate of irregular shape and mutually staggered flaky crystal structure, the gap between the hollow sphere aggregates is filled and is inserted between the matrix and the fiber, the mechanical property and the high-temperature volume stability of the castable are improved, and the thermal conductivity coefficient of the castable is further reduced through the microporous structure of the castable.

Through the addition of the floating beads, the heat conductivity coefficient is further reduced, the fluidity of the castable is improved, and meanwhile, when the floating beads are used at high temperature in a tunnel type heating furnace, the floating beads can partially generate liquid phase reaction due to the existence of low-melting-point impurities, so that the sintering promotion effect is achieved, and the high-temperature strength of the castable is improved.

By adding the nano-silica aerogel powder, the heat conductivity coefficient is further reduced and the heat insulation performance of the castable is improved by utilizing the characteristics of nano-scale pore size and ultralow heat conductivity.

By adding the kyanite powder with the particle size of 80-120 meshes, the characteristic that kyanite decomposes and expands at 1100 ℃, the defect of high-temperature sintering shrinkage of the lightweight castable is made up, the high-temperature volume stability of the castable is improved, and cracking and damage caused by high-temperature shrinkage are avoided.

By adding the refractory fiber, the thermal shock stability of the castable is improved, and the heat insulation performance of the castable is improved; particularly, the refractory fiber containing zirconium or the refractory fiber containing aluminum silicate is discarded after being used by a metallurgical furnace for preparation, so that the cost of the castable is reduced, and the environmental problem caused by the used refractory fiber is solved; the surface of the refractory fiber is modified by adopting a polyethylene glycol aqueous solution with the concentration of 0.7-0.8 g/100mL, so that the interface bonding of the refractory fiber and the dispersion state of the refractory fiber in the castable are improved, and the reinforcing and toughening effects of the refractory fiber are enhanced.

By adding the potassium hexatitanate whisker, the heat conductivity coefficient of the castable is reduced from three aspects of structural heat insulation, physical heat insulation and infrared reflection by utilizing the characteristics of excellent mechanical property, low heat conductivity, negative temperature coefficient and high infrared reflection, and the reinforcing and toughening effects of the reinforcing fiber are further supplemented.

The silica sol is used as a bonding agent, the curing time of the material meeting construction requirements can be effectively controlled by adjusting the pH value, the purposes of shortening the curing time and quickly demolding are achieved, meanwhile, the silica sol is hydrated and gelled in the material, a large number of micropores generated in the forming process can effectively discharge water vapor generated in the material during quick baking, the purposes of quick drying and baking are achieved, and the manufacturing period of the furnace roller is greatly shortened; in addition, compared with a cement bonding system, the silica sol bonding castable has good high-temperature strength and thermal shock resistance stability.

By using fine silica powder and alpha-Al₂O₃The addition of the micro powder effectively improves the rheological property of the castable, and simultaneously, the silicon dioxide micro powder and the Si-O-Si bond space network structure formed in the silica sol use Al₂O₃Firm bonding of microparticlesTogether, and in Al₂O₃The surface of the particles forms a nano-coated micro-composite structure, so that the normal temperature strength of the castable is improved, and an acicular mullite crystal is further formed at the temperature of 800-1200 ℃, so that the castable has excellent strength after high-temperature sintering.

By adding the sintering magnesia coagulant with the grain diameter less than 300 meshes, the reaction of anions on the surface of the sol can be promoted, the formation and the gelling rate of siloxane groups are accelerated, the normal-temperature strength of the silica sol combined castable is improved, and the demolding and curing time is shortened.

By adding the citric acid retarder, citric acid reacts with MgO particles in the sintered magnesia to generate a magnesium citrate protective layer with low solubility, and the hydration speed of magnesium oxide can be controlled, so that the viscosity of silica sol slurry is reduced, the fluidity of the castable is improved, the coagulation and hardening of a matrix are promoted, and the normal temperature strength of a sample is improved.

By the optimized combination of the FS10 high-efficiency water reducing agent and the sodium tripolyphosphate, the performance short slab of a single water reducing agent is avoided, the construction fluidity of the castable is improved, the water adding amount of the castable is reduced, and the effect of high water reducing rate and no segregation is achieved.

By adding the RK-720F silicon polyether defoaming agent, the formation of bubbles in the colloid material in the process of stirring the castable by adding water is inhibited, the adhesion of refractory powder around the bubbles is avoided, the fluidity of the castable is improved, meanwhile, the formation of the bubbles on the surfaces of the colloid material, the alumina hollow sphere and the microporous calcium hexaluminate lightweight aggregate is also inhibited, the interface combination condition of the alumina hollow sphere and the microporous calcium hexaluminate lightweight aggregate is improved, and the mechanical property of the castable is improved.

Through the comprehensive measures, the invention realizes the purposes of rapid construction and baking and improvement of mechanical strength and heat insulation performance, and various raw materials are common commercial raw materials or waste refractory materials, and have the advantages of easy obtainment of raw materials and low cost. The water-cooling furnace roller heat-insulating lining prepared by the castable disclosed by the invention has the advantages of short maintenance and drying time, excellent heat-insulating property and thermal shock resistance stability, good mechanical property and the like, and not only can effectively reduce the water-cooling heat loss of the high-temperature water-cooling furnace roller of the thin slab continuous casting and rolling tunnel type heating furnace, improve the heat efficiency of the heating furnace, prolong the service life of the furnace roller heat-insulating layer, but also can reduce the drying time of the furnace roller and shorten the repair period.

Drawings

FIG. 1 is a scanning electron microscope photograph of a sample subjected to heat treatment at 1100 ℃ for 3h by using the quick-drying hollow sphere heat-insulating refractory castable in example 1;

FIG. 2 is a scanning electron microscope photograph of a sample subjected to heat treatment at 1100 ℃ for 3h by using the quick-drying hollow sphere heat-insulating refractory castable in example 1.

Detailed Description

In order to better explain the invention, the following further illustrate the main content of the invention in connection with specific examples, but the content of the invention is not limited to the following examples.

In the following embodiment, the silicon micropowder is active silicon micropowder with the granularity less than or equal to 500 meshes; the alpha-Al₂O₃The granularity of the micro powder is less than or equal to 500 meshes.

Example 1

A quick-drying hollow sphere heat-insulating refractory castable comprises the following raw materials in percentage by weight: 40 percent of alumina hollow sphere, 5 percent of microporous calcium hexaluminate lightweight aggregate, 3 percent of floating bead with the granularity of 200 meshes, and nano-silica aerogel powder (the density is less than or equal to 0.05 g/cm)³The specific surface area is more than or equal to 600m²5 percent of the mixture per gram), 8 percent of kyanite powder with the granularity of 120 meshes, 5.37 percent of first-grade high-alumina clinker powder with the granularity of 200 meshes, 15 percent of refractory fiber, 2 percent of potassium hexatitanate whisker (the diameter is 2 to 4 mu m, the length-diameter ratio is 10 to 20), 3 percent of silicon micropowder and alpha-Al₂O₃13% of micro powder, 0.3% of composite water reducing agent, 0.03% of RK-720F silicon polyether defoaming agent (produced by Xiamen Rui Man chemical technology Co., Ltd.), 0.2% of sintered magnesia powder with the granularity of 300 meshes (the MgO content is more than or equal to 98%) and 0.1% of citric acid; in addition, 30% of silica sol was added.

The alumina hollow spheres are in particle grading, and specifically comprise 15 wt% of alumina hollow spheres with the particle size of less than or equal to 5mm and less than 3mm, 17 wt% of alumina hollow spheres with the particle size of less than or equal to 3mm and less than 1mm, 8 wt% of alumina hollow spheres with the particle size of less than or equal to 1mm and less than 0.2mm, and the total amount of the alumina hollow spheres is 40%.

The particle size of the microporous calcium hexaluminate lightweight aggregate is 2-3 mm, and the average pore diameter of the micropores is less than or equal to 6 mu m.

The refractory fiber is prepared from waste zirconium-containing refractory fiber after silicon steel continuous annealing furnace, and is specifically characterized in that the recovered waste zirconium-containing refractory fiber is cut into short fibers of 5-10 mm, and the short fibers are sprayed on the surface of the short fibers by using polyethylene glycol (PEG-4000) aqueous solution with the concentration of 0.7g/100mL for modification treatment.

The compound water reducing agent is a mixture of an FS10 high-efficiency water reducing agent and sodium tripolyphosphate, wherein the FS10 high-efficiency water reducing agent accounts for 90% of the total mass of the compound water reducing agent, and the sodium tripolyphosphate accounts for 10% of the total mass of the compound water reducing agent.

SiO in the silica sol₂The content is 40%, and the pH value is 9.0-9.5.

Example 2

A quick-drying hollow sphere heat-insulating refractory castable comprises the following raw materials in percentage by weight: 45 percent of alumina hollow spheres, 7.73 percent of microporous calcium hexaluminate lightweight aggregate, 5 percent of floating beads with the granularity of 180 meshes, and nano-silica aerogel powder (the density is less than or equal to 0.05 g/cm)³The specific surface area is more than or equal to 600m²3 percent of the mixture,/g), 5 percent of kyanite powder with the granularity of 120 meshes, 8 percent of first-grade high-aluminum clinker powder with the granularity of 200 meshes, 10 percent of refractory fiber, 2 percent of potassium hexatitanate whisker (the diameter is 2 to 4 mu m, the length-diameter ratio is 10 to 20), 4 percent of silicon micropowder, and alpha-Al₂O₃10% of micro powder, 0.1% of composite water reducing agent, 0.02% of RK-720F silicon polyether defoaming agent, 0.1% of sintered magnesia powder with the granularity of 300 meshes (the MgO content is more than or equal to 98%), and 0.05% of citric acid; in addition, 20% of silica sol was added.

The alumina hollow spheres are in particle grading, and specifically comprise 14% by weight of alumina hollow spheres with the particle size of less than or equal to 5mm and less than 3mm, 17% by weight of alumina hollow spheres with the particle size of less than or equal to 3mm and less than 1mm, 14% by weight of alumina hollow spheres with the particle size of less than or equal to 1mm and less than 0.2mm, and the total amount of the alumina hollow spheres is 45%.

The particle size of the microporous calcium hexaluminate lightweight aggregate is 2-3 mm, and the average pore diameter of the micropores is less than or equal to 6 mu m.

The refractory fiber is prepared from waste zirconium-containing refractory fiber after silicon steel continuous annealing furnace, and is specifically characterized in that the recovered waste zirconium-containing refractory fiber is cut into short fibers of 5-10 mm, and the short fibers are sprayed on the surface of the short fibers by using polyethylene glycol (PEG-4000) aqueous solution with the concentration of 0.7g/100mL for modification treatment.

The compound water reducing agent is a mixture of an FS10 high-efficiency water reducing agent and sodium tripolyphosphate, wherein the FS10 high-efficiency water reducing agent accounts for 80% of the total mass of the compound water reducing agent, and the sodium tripolyphosphate accounts for 20% of the total mass of the compound water reducing agent.

SiO in the silica sol₂The content is 40%, and the pH value is 9.0-9.5.

Example 3

A quick-drying hollow sphere heat-insulating refractory castable comprises the following raw materials in percentage by weight: 35 percent of alumina hollow sphere, 8 percent of microporous calcium hexaluminate lightweight aggregate, 4 percent of floating bead with the granularity of 160 meshes, and nano-silica aerogel powder (the density is less than or equal to 0.05 g/cm)³The specific surface area is more than or equal to 600m²4 percent of silicon powder, 7.2 percent of kyanite powder with the granularity of 120 meshes, 5 percent of first-grade high-aluminum clinker powder with the granularity of 200 meshes, 14 percent of refractory fiber, 3 percent of potassium hexatitanate whisker (the diameter is 2 to 4 mu m, the length-diameter ratio is 10 to 20), 4 percent of silicon micropowder and alpha-Al₂O₃15% of micro powder, 0.3% of composite water reducing agent, 0.05% of RK-720F silicon polyether defoaming agent, 0.3% of sintered magnesia powder with the granularity of 300 meshes (the MgO content is more than or equal to 98%) and 0.15% of citric acid; in addition, 28% of silica sol was added.

The alumina hollow spheres are in particle grading, and specifically comprise 10 wt% of alumina hollow spheres with the particle size of less than or equal to 5mm and less than 3mm, 10 wt% of alumina hollow spheres with the particle size of less than or equal to 3mm and less than 1mm, 15 wt% of alumina hollow spheres with the particle size of less than or equal to 1mm and less than 0.2mm, and the total amount of the alumina hollow spheres is 35%.

The particle size of the microporous calcium hexaluminate lightweight aggregate is 2-3 mm, and the average pore diameter of the micropores is less than or equal to 6 mu m.

The refractory fiber is prepared from waste aluminum silicate refractory fiber after being used in a cold rolling continuous annealing furnace, and specifically, the recovered waste zirconium-containing refractory fiber is cut into short fibers of 5-10 mm, and the short fibers are sprayed on the surface of the refractory fiber by using polyethylene glycol (PEG-4000) aqueous solution with the concentration of 0.7g/100mL for modification treatment.

The compound water reducing agent is a mixture of an FS10 high-efficiency water reducing agent and sodium tripolyphosphate, wherein the FS10 high-efficiency water reducing agent accounts for 85% of the total mass of the compound water reducing agent, and the sodium tripolyphosphate accounts for 15% of the total mass of the compound water reducing agent.

SiO in the silica sol₂The content is 30%, and the pH value is 9.0-9.5.

Example 4

A quick-drying hollow sphere heat-insulating refractory castable comprises the following raw materials in percentage by weight: 38 percent of alumina hollow sphere, 8 percent of microporous calcium hexaluminate lightweight aggregate, 4 percent of floating bead with the granularity of 80 meshes, and nano-silica aerogel powder (the density is less than or equal to 0.05 g/cm)³The specific surface area is more than or equal to 600m²5 percent of silicon powder, 6 percent of kyanite powder with the granularity of 80 meshes, 6.54 percent of first-grade high-aluminum clinker powder with the granularity of 200 meshes, 12 percent of refractory fiber, 3 percent of potassium hexatitanate whisker (the diameter is 2 to 4 mu m, the length-diameter ratio is 10 to 20), 2 percent of silicon micropowder, and alpha-Al₂O₃15% of micro powder, 0.2% of composite water reducing agent, 0.03% of RK-720F silicon polyether defoaming agent, 0.15% of sintered magnesia powder with the granularity of 300 meshes (the MgO content is more than or equal to 98%) and 0.08% of citric acid; in addition, silica sol 25% was added.

The alumina hollow spheres are in particle grading, and specifically comprise 11 wt% of alumina hollow spheres with the particle size of less than or equal to 5mm and less than 3mm, 18 wt% of alumina hollow spheres with the particle size of less than or equal to 3mm and less than 1mm, 9 wt% of alumina hollow spheres with the particle size of less than or equal to 1mm and less than 0.2mm, and the total is 38% of the alumina hollow spheres.

The particle size of the microporous calcium hexaluminate lightweight aggregate is 2-3 mm, and the average pore diameter of the micropores is less than or equal to 6 mu m.

The refractory fiber is prepared from waste aluminum silicate refractory fiber after being used in a cold rolling continuous annealing furnace, and specifically, the recovered waste zirconium-containing refractory fiber is cut into short fibers of 5-10 mm, and the short fibers are sprayed on the surface of the refractory fiber by using polyethylene glycol (PEG-4000) aqueous solution with the concentration of 0.7g/100mL for modification treatment.

The compound water reducing agent is a mixture of an FS10 high-efficiency water reducing agent and sodium tripolyphosphate, wherein the FS10 high-efficiency water reducing agent accounts for 75% of the total mass of the compound water reducing agent, and the sodium tripolyphosphate accounts for 25% of the total mass of the compound water reducing agent.

SiO in the silica sol₂The content is 30%, and the pH value is 9.0-9.5.

Example 5

A quick-drying hollow sphere heat-insulating refractory castable comprises the following raw materials in percentage by weight: 41 percent of alumina hollow spheres, 6.54 percent of microporous calcium hexaluminate lightweight aggregate, 5 percent of floating beads with the granularity of 200 meshes, and nano-silica aerogel powder (the density is less than or equal to 0.05 g/cm)³The specific surface area is more than or equal to 600m²5 percent of the mixture per gram), 5 percent of kyanite powder with the granularity of 80 meshes, 8 percent of first-grade high-aluminum clinker powder with the granularity of 200 meshes, 10 percent of refractory fiber, 2 percent of potassium hexatitanate whisker (the diameter is 2 to 4 mu m, the length-diameter ratio is 10 to 20), 3 percent of silicon micropowder, and alpha-Al₂O₃14 percent of micro powder, 0.2 percent of composite water reducing agent, 0.03 percent of RK-720F silicon polyether defoaming agent, 0.15 percent of sintered magnesia powder with the granularity of 300 meshes (the MgO content is more than or equal to 98 percent) and 0.08 percent of citric acid; in addition, 23% of silica sol was added.

The aluminum oxide hollow sphere is in particle grading, and specifically comprises 15 wt% of aluminum oxide hollow spheres with the particle size of less than or equal to 5mm and less than 3mm, 16 wt% of aluminum oxide hollow spheres with the particle size of less than or equal to 3mm and less than 1mm, 10 wt% of aluminum oxide hollow spheres with the particle size of less than or equal to 1mm and less than 0.2mm, and the total is 41% of the aluminum oxide hollow spheres.

The particle size of the microporous calcium hexaluminate lightweight aggregate is 2-3 mm, and the average pore diameter of the micropores is less than or equal to 6 mu m.

The refractory fiber is prepared from waste zirconium-containing refractory fiber after silicon steel continuous annealing furnace, and is specifically characterized in that the recovered waste zirconium-containing refractory fiber is cut into short fibers of 5-10 mm, and the short fibers are sprayed on the surface of the short fibers by using polyethylene glycol (PEG-4000) aqueous solution with the concentration of 0.7g/100mL for modification treatment.

The compound water reducing agent is a mixture of an FS10 high-efficiency water reducing agent and sodium tripolyphosphate, wherein the FS10 high-efficiency water reducing agent accounts for 85% of the total mass of the compound water reducing agent, and the sodium tripolyphosphate accounts for 15% of the total mass of the compound water reducing agent.

SiO in the silica sol₂The content of the components is 40 percent,the pH value is 9.0-9.5.

Performance testing

According to the quick-drying hollow sphere heat-insulating refractory castable in the embodiments 1 to 5, heat-insulating refractory castable is prepared respectively, a 160mm × 40mm × 40mm standard sample is prepared, and after natural curing, demolding and heat treatment, detection can be carried out according to the standard: GB/T3001-2007 and YB/T5291-1999), the detection data are shown in Table 1.

TABLE 1 quick-drying hollow ball heat insulation refractory castable sample performance index

As can be seen from table 1: the bulk density of each sample is 1.20 to 1.35g/cm³The heat-insulating performance of the castable is better than the performance indexes of the castable for the water-cooling furnace roller reported by related data (such as ' the castable for the furnace roller of a roller hearth furnace ', an authorization notice No. CN 100408515C; ' a light heat-insulating castable refractory, a publication No. CN 101792294A; ' the light castable for the CSP furnace roller for heat insulation ', and a publication No. CN 102161593A).

The scanning electron micrographs of the 1100 ℃ x 3h heat-treated sample in example 1 are shown in FIGS. 1-2, from which it can be seen that: the hollow spheres are well combined with the matrix, and the fibers have good reinforcing and toughening effects.

Further, on the basis of the above, the quick-drying hollow sphere heat-insulating refractory castable of the embodiments 1 to 5 is applied to industrial tests, and is subjected to casting molding of a high-temperature water-cooling furnace roller heat-insulating lining of a thin slab continuous casting and continuous rolling tunnel heating furnace, demoulding after 24 hours of curing, and compared with a heavy furnace roller castable (with a density of 2.3 g/cm) combined by aluminate cement³) In other words, take offThe natural curing time after the mould is shortened from 48 to 72 hours to 0 to 12 hours; the furnace roller is made of a heavy furnace roller castable combined with aluminate cement, the temperature is slowly increased to 200 ℃ at the temperature increase speed of 10 ℃/h during baking, then the furnace roller is shut down and naturally cooled to below 70 ℃, and a furnace door is opened; the quick-drying hollow sphere heat-insulating refractory castable furnace roller can be heated to 200 ℃ at a heating rate of 10 ℃/min during baking, is kept at the temperature of 200 ℃ for 4-5 hours, realizes quick heating baking, shortens the baking time from 30 hours to less than 6 hours, has the advantages of short curing and baking time, excellent heat-insulating property and thermal shock resistance stability, good mechanical property and the like, is applied to the high-temperature water-cooling furnace roller heat-insulating protection of a sheet billet continuous casting and rolling tunnel heating furnace, and achieves the good effects of reducing the water-cooling heat loss, improving the heat efficiency of the heating furnace, shortening the construction period and the like.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, many modifications and changes can be made without departing from the inventive concept of the present invention, and these modifications and changes are within the protection scope of the present invention.