High-alumina low-creep insulating refractory mortar

Abstract

The application discloses a high-alumina low-creep heat-insulating refractory mortar. In terms of anhydrous calculation, the mortar is composed of the following components in percentage by mass: recycled white corundum sandblasting powder 40-60%; recycled titanium-iron slag powder 20-30%; calcined alumina powder 7-15%; 95SiC dust extraction powder 3-7%; floating bead powder 4-6%; high-molecular plasticizer 4-6%; additional sodium tripolyphosphate 0.05-0.15%; and additional pure alkali 0.1-0.2%. The calcined alumina powder is a-Al2O3 micro powder obtained by mixing industrial alumina and hydrated alumina powder, high-temperature calcination and grinding treatment, the particles of the powder are mainly in flaky and columnar shapes, and the particle size distribution presents a unimodal structure. The obtained mortar has high adhesive and bending strength, high load softening temperature, small change rate of remelting line, and small high-temperature creep, and a large amount of recycled waste is used, thereby saving mineral resources and having a wide application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of refractory mortar, and particularly relates to high-alumina low-creep heat-insulating refractory mortar. BACKGROUND

[0002] With the rapid development of the steel industry, the increase of refractory materials used for furnace lining is remarkable. Refractory mortar is a kind of joint material used for masonry of refractory bricks, unburned bricks, prefabricated parts or industrial furnace joints. The commonly used amount is about 3-5% of the shaped product. In the past three years, the annual consumption of refractory mortar has reached more than 600,000 tons, and the market demand is huge.

[0003] Refractory mortar is required to have good construction performance, good spreading property, no bleeding, and kneadability to ensure that the mortar joint is full and meets the joint thickness requirement according to the furnace building specification. It is required to have sufficient bonding strength to bond large-volume refractory masonry into a firm whole, excellent volume stability to prevent damage to the masonry due to high-temperature expansion or excessive shrinkage when the temperature fluctuates, good high-temperature performance to effectively resist the erosion of atmosphere and slag, and a certain thermal conductivity when masonry is used for heat-insulating bricks, and small creep.

[0004] High-temperature equipment such as blast furnace hot blast furnace is masonry with refractory materials, which requires the materials to have high load softening temperature and good creep resistance in high-temperature use environment. When the temperature of the hot blast furnace is greater than 1300℃, deformation caused by high-temperature mechanical load, cracking and spalling caused by frequent temperature changes, etc. occur. In particular, high-alumina bricks used for masonry at the top of the hot blast furnace are masonry with traditional high-alumina heat-insulating mortar. Traditional high-alumina heat-insulating mortar uses a large amount of high-alumina powder, which will cause creep deformation and structural damage of the material under the action of long-term high temperature and load. Therefore, it is particularly important to develop low-creep high-alumina heat-insulating refractory mortar.

[0005] Traditional refractory mortar adds a large amount of raw clay, sodium carboxymethyl cellulose, yellow dextrin, phosphate, cement or organic resin, etc. to adjust its various properties in order to meet the basic requirements. During construction, 20-35% of the liquid of the powder quality is added to make it into a slurry that is easy to apply. These binders and additives meet the basic use requirements of the mortar, but affect the high-temperature use performance of the refractory mortar. Especially in the harsh working environment of the top of the hot blast furnace, high-alumina heat-insulating refractory mortar is often the weakest link, which is the root cause of the early shutdown of the masonry body, and seriously affects the safety and service life of the industrial furnace.

[0006] Invention patent CN 201410836277.8 discloses a kind of high-alumina mud and preparation method thereof, using high-alumina powder, dextrin, sodium carboxymethyl cellulose, silicon powder to prepare mud, solve the problem of insufficient water ratio when laying steel ladle high-alumina brick, but there are problems such as large material high-temperature shrinkage and low material load softening temperature.

[0007] Invention patent 202211149068.7 discloses a kind of high-alumina mud and its use method, using special calcined bauxite fine aggregate 35-45%; Alumina powder 6-10%; Submicron SiO2 powder 9-10%; Special calcined bauxite powder 36-48%, aluminum lactate 0.5-1.5%, dispersant 0.3-0.5%. The high-alumina mud has low water content, good density, no low-melting-point binding phase, etc., and can realize synchronous damage of brick and mud. But there are problems such as high material cost and poor material creep performance.

[0008] Invention patent 201510533914.9 discloses a kind of low-temperature sintering refractory mud and its preparation method, using clay powder, red beryl powder, carboxymethyl cellulose, dextrin, boron glass and sodium tripolyphosphate, solving the problem of refractory mud in hot blast furnace premixing chamber that cannot be sintered, but there are problems such as poor high-temperature performance of the material, low load softening temperature of the material, and easy melting of the material at high temperature. SUMMARY

[0009] The purpose of the present application is to provide a kind of high-alumina low-creep heat-insulating refractory mud, which has strong bonding and bending strength, high load softening temperature, small mud re-burning line change rate, small high-temperature creep and excellent comprehensive performance.

[0010] To solve the above technical problems, the present application adopts the following technical solutions:

[0011] A kind of high-alumina low-creep heat-insulating refractory mud is provided, and the components of the mud are as follows in terms of mass percentage: recycled white corundum sandblasting powder 40-60%; recycled titanium slag powder 20-30%; calcined alumina powder 7-15%; 95SiC dust extraction powder 3-7%; floating bead powder 4-6%; high molecular plasticizer 4-6%; additional sodium tripolyphosphate 0.05-0.15%; and additional soda ash 0.1-0.2%.

[0012] The calcined alumina powder is a-Al2O3 micro powder obtained by mixing industrial alumina and hydrated alumina powder in a mass ratio of 48-50:1, calcining at 1450-1500℃ for 4.5-5.5h, and then grinding and treating, the particles of the calcined alumina powder are mainly in the form of flakes and columns, and the particle size distribution presents a unimodal structure, the particle size distribution D 10= 0.21-0.25 μm, D50 = 0.61-0.68 μm, D90 = 2.18-2.25 μm, D99 = 5.31-5.48 μm.

[0013] According to the above scheme, the Al2O3 content in the calcined alumina powder is 99.5-99.8 wt%, and the Na2O content is 0.15-0.30 wt%.

[0014] According to the above scheme, the recycled white corundum blasting powder is a dust collection powder collected and treated during the production of white corundum powder.

[0015] Preferably, the Al2O3 content in the recycled white corundum blasting powder is 93.0-96.5 wt%, the SiO2 content is 1.0-2.0 wt%, and the Fe2O3 content is 0.5-1.5 wt%.

[0016] Preferably, the 0.074mm -0.5mm particle size accounts for 20-30% and the <0.074mm particle size accounts for 70-80%.

[0017] According to the above scheme, the recycled titanium slag powder is a ground powder obtained by recycling the waste slag produced during the smelting of ferrotitanium alloy, and the main phases are calcium hexaluminate, calcium dialuminate and calcium titanate.

[0018] Preferably, the Al2O3 content in the recycled titanium slag powder is 74.0-78.0 wt%, the SiO2 content is 0.3-0.7 wt%, the Fe2O3 content is 0.15-0.25 wt%, the TiO2 content is 11.3-13.9 wt%, the CaO content is 9.0-11.5 wt%, and the MgO content is 0.7-1.3 wt%.

[0019] Preferably, the 0.074mm -0.5mm particle size accounts for 10-40% and the <0.074mm particle size accounts for 60-90%.

[0020] According to the above scheme, the 95SiC dust collection powder is a waste material recycled during the production of silicon carbide fine powder, with a SiC content of 94.5-96.5 wt%, a SiO2 content of 1.0-1.5 wt%, and a particle size of <0.044mm.

[0021] According to the above scheme, the Al2O3 content in the floating bead powder is 25-35 wt%, the SiO2 content is 45-65 wt%, the 0.075mm -0.5mm particle size accounts for 25-55%, and the <0.074mm particle size accounts for 45-75%.

[0022] According to the above scheme, the high polymer plasticizer is prepared by the reaction of carboxymethyl cellulose, polyurethane and ethylene glycol ether.

[0023] According to the above scheme, the soda ash is Na2CO3, and the purity is greater than 99.5%, and the color is white.

[0024] According to the above scheme, the mud further comprises 20-25% of water.

[0025] According to the above scheme, the high-alumina refractory mud has Al2O3≥ 70%, the bonding rupture strength (110℃×24h)≥ 3.0 MPa, the bonding rupture strength (1500℃×3h)≥ 8.0 MPa, the load softening temperature (0.2MPa, T2.0)≥1600℃, the bonding time (S) 60-180s, the change rate of the re-burning line (1500℃×3h)-1%-+1%, and the low creep rate -0.3%-+0.3%.

[0026] The application provides a high-alumina low-creep heat-insulating refractory mud, which comprises a binder of calcined active alumina powder, recycled white corundum sandblasting powder, recycled titanium slag powder and a high polymer plasticizer, and is further combined with 95SiC dust extraction powder, floating bead powder, sodium tripolyphosphate and soda ash.

[0027] The calcined active alumina is obtained by high-temperature calcination of industrial alumina and hydrated alumina powder, has small particle size, a unimodal particle size distribution and an interlaced structure of flakes and columns, has self-binding property, can be directly used as a binder of high-alumina mud, and effectively avoids the generation of low-melting phases at high temperatures when traditional binders such as yellow dextrin, clay and aluminum dihydrogen phosphate solution are used.

[0028] The recycled titanium slag powder contains a certain TiO2, which can promote the reaction of Al2O3 and SiO2 in the high-aluminum slurry to generate mullite and amorphous SiO2 at 1300 DEG C, and the volume expansion is generated along with the reaction, and the amorphous SiO2 reacts with the calcined bauxite powder to generate secondary mullitization, and the corresponding volume expansion is generated. A large amount of SiC is contained in the recycled dust powder, and the SiC starts to oxidize and decompose to generate SiO2 at about 1250 DEG C, and the volume expansion is generated, and the generated SiO2 reacts with the calcined bauxite powder to generate secondary mullitization, and the volume expansion is generated. And these reactions can occur quickly and efficiently, which is also based on the characteristics of the calcined bauxite powder, such as small particle size, large specific surface area, high activity and close combination with the components of the slurry as the binder. At the same time, the calcined bauxite powder participates in the mullitization reaction, further promotes the combination between the components of the slurry, and better plays the role of the binder. It is just because the volume expansion generated by the multiple mullitization offsets the shrinkage of the high-aluminum slurry at high temperature, so that the multiple peak superposition effect of the high-aluminum slurry softening temperature under load appears, and the high-aluminum slurry softening temperature under load is further improved.

[0029] In addition, the high molecular plasticizer can further enhance the strength of the calcined active alumina powder as the binder at low temperature, because the high molecular plasticizer improves the viscosity of the material, and various powders are wrapped more tightly. The high molecular plasticizer will be calcined at high temperature, and will not affect the high temperature performance, and can keep the relative "purity" of the material at high temperature. Finally, the high temperature performance of the material can also be improved.

[0030] The beneficial effects of the present application are as follows:

[0031] The present application provides a high-alumina low-creep heat-insulating refractory slurry, which uses calcined active alumina powder as a binder, cooperates with recycled white corundum blasting powder, recycled titanium slag powder and high molecular plasticizer, and further cooperates with 95SiC dust powder, floating bead powder, sodium tripolyphosphate and soda ash, so that the obtained slurry has low water addition ratio, high bending strength, high high-alumina slurry softening temperature under load, small change rate of slurry re-burning line, small high-temperature creep and excellent comprehensive performance, avoids the problem that the sintering shrinkage of high-alumina heat-insulating slurry is intensified, and causes the slurry and the brick to be separated from the surface and the brick to be dropped, and simultaneously uses a large amount of recycled waste materials, protects the environment, saves mineral resources, and has a wide application prospect. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.

[0033] The specific indexes of the raw materials in the embodiment of the present application are as follows:

[0034] The recycled white corundum blasting powder has an Al2O3 content of 93.0-96.5 wt%, a SiO2 content of 1.0-2.0 wt%, and a Fe2O3 content of 0.5-1.5 wt%, and is obtained by collecting and processing the dust generated in the production of white corundum powder, wherein the content of 0.074 mm-0.5 mm particles is 20-30% and the content of <0.074 mm particles is 70-80%.

[0035] The recycled titanium-iron slag powder has an Al2O3 content of 74.0-78.0 wt%, a SiO2 content of 0.3-0.7 wt%, a Fe2O3 content of 0.15-0.25 wt%, a TiO2 content of 11.3-13.9 wt%, a CaO content of 9.0-11.5 wt%, and a MgO content of 0.7-1.3 wt%, and is obtained by collecting and grinding the slag generated in the smelting of titanium-iron alloy, wherein the content of 0.074 mm-0.5 mm particles is 10-40% and the content of <0.074 mm particles is 60-90%.

[0036] The 95SiC dust is a waste material collected in the production of fine silicon carbide powder, and has a SiC content of 94.5-96.5 wt% and a SiO2 content of 1.0-1.5 wt%, and a particle size of <0.044 mm.

[0037] The floating bead powder has an Al2O3 content of 25-35 wt% and a SiO2 content of 45-65 wt%, wherein the content of 0.075 mm-0.5 mm particles is 25-55% and the content of <0.074 mm particles is 45-75%.

[0038] The high-efficiency mud plasticizing binder PT2301 is a white powder produced by a certain chemical company in Wuhan, and is a high-molecular plasticizing binder obtained by the reaction of carboxymethyl cellulose, polyurethane and ethylene glycol ether at a ratio of 2:1:10. The plasticizing binder has high purity, can thicken and retain water, can adjust the setting time of mud, can improve the setting strength of mud, and has a significant effect on improving the softening temperature under load of mud.

[0039] The soda ash is Na2CO3, and has a purity of greater than 99.5% and a white color.

[0040] The calcined alumina powder is a-Al2O3 micro powder obtained by mixing 98% industrial alumina with 2% hydrated alumina powder, calcining at 1480°C for 5 h, and then grinding, and has a flaky and columnar particle shape, an Al2O3 content of 99.5-99.8 wt%, and a Na2O content of 0.15-0.30 wt%. The calcined alumina powder has a unimodal particle size distribution, and the particle size distribution D10 =0.23 μm, D50=0.65 μm, D90=2.21 μm, D99=5.38 μm. The calcined alumina powder has certain viscosity after being dissolved in water. The demolding pressure resistance of the alumina powder added to 35% pure water and stirred into a shape can reach 2 MPa.

[0041] Example 1

[0042] A high-alumina low-creep heat-insulating refractory mortar is provided, each component of the mortar is calculated by mass percentage as follows:

[0043] Recycled white corundum blasting powder 40%

[0044] Recycled titanium-iron slag powder 30%

[0045] Calcined alumina powder 15%

[0046] 95SiC dust extraction powder 4%

[0047] Floating bead powder 6%

[0048] High-efficiency mortar plasticizing binder PT2301 5%

[0049] Sodium tripolyphosphate (added) 0.1%

[0050] Soda ash (added) 0.1%

[0051] Example 2

[0052] A high-alumina low-creep heat-insulating refractory mortar is provided, each component of the mortar is calculated by mass percentage as follows:

[0053] Recycled white corundum blasting powder 50%

[0054] Recycled titanium-iron slag powder 25%

[0055] Calcined alumina powder 10%

[0056] 95SiC dust extraction powder 5%

[0057] Floating bead powder 5%

[0058] High-efficiency mortar plasticizing binder PT2301 5%

[0059] Sodium tripolyphosphate (added) 0.12%

[0060] Soda ash (added) 0.12%

[0061] Example 3

[0062] A high-alumina low-creep heat-insulating refractory mortar is provided, each component of the mortar is calculated by mass percentage as follows:

[0063] Recovery white corundum blasting powder 60%

[0064] Recovery titanium slag powder 20%

[0065] Calcined alumina powder 7%

[0066] 95SiC dust 5%

[0067] Floating bead powder 4%

[0068] High-efficiency mud plasticizing binder PT2301 4%

[0069] Sodium tripolyphosphate (added) 0.15%

[0070] Soda ash (added) 0.2%

[0071] Comparative Example 1

[0072] A high-alumina heat-insulating refractory mud combined with traditional yellow dextrin and clay is provided, and the components are as follows in terms of mass percentage:

[0073] White corundum powder 50%, 83 high-alumina powder 33.5%, floating bead powder 4%, 98 silicon carbide powder 5%, clay powder 6%, yellow dextrin 1.5%, sodium tripolyphosphate 0.18% (added), and soda ash 0.15% (added).

[0074] Table 1: Physical and chemical performance test results of the high-alumina low-creep heat-insulating refractory mud of the present application

[0075]

[0076] The high-alumina low-creep heat-insulating refractory mud obtained by the embodiments of the present application is applied to Indonesian export hot blast furnace projects, a steel plant project in Jiangsu, a hot blast furnace project in Shandong, etc., and has high mud bonding strength, high load softening temperature, and small high-temperature creep, thereby avoiding the problem of mud and brick peeling and brick falling caused by the intensification of sintering shrinkage of high-alumina heat-insulating mud. Meanwhile, the invented mud uses a large amount of recycled waste materials, protects the environment, and saves mineral resources.

[0077] The above embodiments are only examples for clearly illustrating the present application and are not intended to limit the embodiments. Based on the above description, those skilled in the art can make other different forms of changes or modifications. Here, it is not necessary or possible to exhaust all embodiments. Therefore, the obvious changes or modifications still fall within the scope of the present application.

Claims

1. A high alumina low creep insulating refractory mortar, characterized in that, The mud components are as follows in terms of mass percentage on an anhydrous basis: recycled white corundum blasting powder 40-60%; recycled titanium-iron slag powder 20-30%; calcined alumina powder 7-15%; 95 SiC dust extraction powder 3-7%; floating bead powder 4-6%; high molecular plasticizer 4-6%; additional sodium tripolyphosphate 0.05-0.15%; additional soda ash 0.1-0.2%; wherein: The calcined alumina powder is α-Al2O3 micro powder obtained by mixing industrial alumina and hydrated alumina powder in a mass ratio of 48-50:1, calcining at 1450-1500°C for 4.5-5.5h, and then grinding and processing, wherein the particles of the calcined alumina powder are mainly in the form of sheets and columns, the particle size distribution presents a unimodal structure, the particle size distribution D 10 =0.21-0.25μm, D50=0.61-0.68μm, D90=2.18-2.25μm, D99=5.31-5.48μm. The recycled white corundum blasting powder is dust collected and treated during production of white corundum powder.

2. The refractory slurry of claim 1, wherein, The calcined alumina powder has an Al2O3 content of 99.5-99.8wt% and a Na2O content of 0.15-0.30wt%.

3. The refractory slurry of claim 1, wherein, The recycled titanium-iron slag powder is obtained by grinding recycled waste slag produced during smelting of titanium-iron alloy, and the main phases are calcium hexaluminate, calcium dialuminate and calcium titanate.

4. The refractory slurry of claim 1, wherein, The recycled white corundum blasting powder has an Al2O3 content of 93.0-96.5wt%, a SiO2 content of 1.0-2.0wt% and a Fe2O3 content of 0.5-1.5wt%; the recycled titanium-iron slag powder has an Al2O3 content of 74.0-78.0wt%, a SiO2 content of 0.3-0.7wt%, a Fe2O3 content of 0.15-0.25wt%, a TiO2 content of 11.3-13.9wt%, a CaO content of 9.0-11.5wt% and a MgO content of 0.7-1.3wt%.

5. The refractory slurry of claim 1, wherein, The recycled white corundum blasting powder has a particle size of 0.074mm-0.5mm of 20-30% and a particle size of <0.074mm of 70-80%; the recycled titanium-iron slag powder has a particle size of 0.074mm-0.5mm of 10-40% and a particle size of <0.074mm of 60-90%.

6. The refractory slurry of claim 1, wherein, The 95 SiC dust extraction powder is waste material recycled during production of silicon carbide fine powder, has a SiC content of 94.5-96.5wt%, a SiO2 content of 1.0-1.5wt% and a particle size of <0.044mm; the floating bead powder has an Al2O3 content of 25-35wt% and a SiO2 content of 45-65wt%, wherein the particle size of 0.075mm-0.5mm is 25-55% and the particle size of <0.074mm is 45-75%.

7. The refractory slurry of claim 1, wherein, The high molecular plasticizer is prepared by reaction of carboxymethyl cellulose, polyurethane and glycol ether.

8. The refractory slurry of claim 7, wherein, The molar ratio of carboxymethyl cellulose, polyurethane and glycol ether is (1.5-2):1:(9-11).

9. The refractory slurry of claim 1, wherein, The mud further comprises additional water of 20-25%.

10. The refractory slurry of claim 1, wherein, In the refractory mud, Al2O3≥70%, the bonding and bending strength at 110℃×24h≥3.0 MPa, the bonding and bending strength at 1500℃×3h≥8.0 MPa, the 0.2MPa, T2.0 load softening temperature≥1600℃, the bonding time is 60-180s, the change rate of re-burning line at 1500℃×3h is -1%-+1%, and the creep rate at 1500℃×3h, 0.1MPa is -0.3%-+0.3%.

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