Fire clay mortar for improving the bonding strength of refractory bricks and its preparation method

Abstract

The application discloses fire clay for improving the bonding strength of refractory brick masonry and a preparation method thereof. The fire clay comprises 48-52% of clay raw material powder, 18-22% of soft clay, 8-12% of high alumina clinker powder, 10-12% of a binder, 1-2% of an additive and the balance of water in percentage by mass. The preparation method of the fire clay comprises the following steps: S1, batching, S2, mixing materials, and S3, mixing. Compared with the binder applied in the preparation process of the fire clay in the prior art, the binder has higher bonding strength and lower requirement for temperature conditions, and still has higher bonding strength at normal temperature, so that the binder can be more widely used in the refractory brick masonry process.

Description

Technical Field

[0001] This invention relates to the field of refractory mortar preparation technology, specifically to a refractory mortar for improving bonding strength and its preparation method. Background Technology

[0002] The raw materials for refractory mortar include refractory powder, binder, and additives. Almost all refractory raw materials can be made into powder for refractory mortar preparation; the types and amounts of binders and additives depend on the material and application of the refractory mortar.

[0003] The particle size distribution of refractory mortar significantly impacts its performance. Too many coarse particles reduce its spreadability, increase joint width, and make it prone to sedimentation, stratification, and shortened bonding time. Conversely, too few coarse particles make it difficult to maintain joint thickness, leading to increased high-temperature shrinkage. The quality of water used in the refractory mortar, the quality of the refractory bricks, the joint size, and the bonding strength of the refractory mortar also affect its performance. High bonding strength in refractory mortar results in good overall integrity, airtightness, and high strength in the refractory brickwork. Furthermore, high bonding strength significantly influences heat loss and furnace shell temperature in electric furnaces.

[0004] Among the existing methods for preparing refractory mortar, the method of adding an appropriate amount of plastic clay as a binder and plasticizer to refractory clinker powder is widely used. However, its strength at room temperature is low, and it needs to form a ceramic bond at high temperature to achieve higher strength. Another method is to use hydraulic, air-hardening, or thermohardening binders as binders to chemically bond and prepare refractory mortar. This method produces a certain chemical reaction and hardens before the temperature of forming a ceramic bond is lowered, losing its original plasticity and bonding ability, and can no longer be used as a refractory material.

[0005] Based on this, this application proposes a fire mortar for refractory brick masonry with improved bonding strength and a preparation method thereof. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the present invention provides a fire mortar for refractory brick masonry with improved bonding strength and a preparation method thereof.

[0007] The technical solution of the present invention is: a fire mortar for refractory brick masonry that improves bonding strength, comprising, by mass percentage, 48-52% clay clinker powder, 18-22% soft clay, 8-12% high-alumina clinker powder, 10-12% binder, 1-2% additives, and the balance being water.

[0008] The binder is composed of sodium carboxymethyl cellulose, modified wheat straw fiber, and water-reducing agent in a weight ratio of 5~7:2~3:0.5~1.5;

[0009] The additive is composed of additive A and additive B in a weight ratio of 2 to 3:1;

[0010] Additive A is composed of silicon dioxide and mica mineral fiber or talc mineral fiber in equal weight ratio; all of the above additives have a filling effect, silicon dioxide can provide stable physical properties and compressive strength, and mica mineral fiber and talc mineral fiber have good fire resistance and insulation properties, which can improve the material properties.

[0011] The preparation method of additive B is as follows:

[0012] 1) Weigh out nano-silicon carbide and sodium silicate at a weight ratio of 1:1 and mix them to obtain a mixture. Then, add deionized water to the mixture at a weight-to-volume ratio of 10~15g:80~90mL and stir for 15~20min to obtain a dispersion.

[0013] 2) Weigh out 3-5 wt% of NS and 20-30 wt% of sodium lignosulfonate respectively and transfer them to a magnetic stirrer. Then add the dispersion to the magnetic stirrer, adjust the magnetic stirring speed to 500-700 rpm, the magnetic stirring power to 15-30 W, and the magnetic stirring time to 5-7 min.

[0014] 3) The product after magnetic stirring is cured for 28 to 30 days to obtain additive B;

[0015] Explanation: In the preparation method of additive B, the dispersion effect of fire clay can be improved by dispersing sodium lignosulfonate. The addition of NS can reduce the microporosity of the interface and generate more high-density hydrated calcium silicate, resulting in stronger compressive strength. At the same time, NS increases the Young's modulus of the weakest surface in the transition zone of the bonding interface, making the entire bonding interface transition zone more uniform, thereby improving its bonding strength. Nano-silicon carbide and sodium silicate have high surface energy and can generate strong interactions with sodium lignosulfonate molecules, thereby effectively adsorbing and dispersing sodium lignosulfonate. The additive B prepared by the above method has strong retarding power, good fluidity and strong bonding strength, further extending the hardening time of fire clay and preventing the fire clay from hardening before ceramic bonding and losing its original plasticity.

[0016] Furthermore, the environment for the maintenance treatment is: temperature 24~26℃, humidity ≤30%RH;

[0017] Note: The above-mentioned curing treatment can effectively reduce the growth of mold in materials and effectively prevent the materials from decomposing or deteriorating.

[0018] Further, the preparation method of the modified wheat straw fiber is as follows: Weigh wheat straw fiber according to the weight ratio of sodium hydroxide solution to wheat straw fiber of 104~105:95~100 and soak it in sodium hydroxide solution with a mass concentration of 0.08~0.1mol / L. Let it stand for 5~7h. Then pour the obtained solid product into an ultrasonic vibration device with a vibration frequency of 30~50kHz and a vibration amplitude of 1~2μm for refining treatment for 1~2h. During the treatment, epoxy resin is added according to the weight volume ratio of solid product to epoxy resin of 5~7g:45~55mL. Stir for 30~50min to obtain modified wheat straw fiber.

[0019] Explanation: The above method first uses sodium hydroxide with a mass concentration of 0.08~0.1 mol / L to treat wheat straw fibers, which can improve the surface structure of the wheat straw fibers, making the wheat straw fibers more effective in enhancing the bonding strength of sodium carboxymethyl cellulose. Epoxy resin is a material with high bonding strength under various temperature and humidity conditions. Therefore, the addition of epoxy resin can be highly compatible with the modified wheat straw fibers, further improving the overall filling performance of the adhesive. It can fully fill the micropores and defects on the surface of the adhered objects, forming a dense and smooth bonding interface, thereby improving its bonding effect. Ultrasonic refining treatment can increase the specific surface area of ​​wheat straw fibers, thereby allowing them to react more fully with epoxy resin, and thus improving the bonding strength.

[0020] Furthermore, in the preparation process of modified wheat straw fiber, the stirring speed is adjusted from 150 to 200 r / min according to the vibration frequency. The adjustment method is divided into the following stages:

[0021] Phase 1: While maintaining the vibration frequency at 30~35kHz, the stirring speed is increased from an initial speed of 150r / min to 200r / min at a frequency of 5r / min.

[0022] Phase 2: Continue to adjust the vibration frequency to maintain it at 36~40kHz. At this time, the stirring speed will start to decrease from 10r / min to 150~170r / min and then be maintained.

[0023] Phase 3: When the vibration frequency rises to 41~50kHz, the stirring speed is increased from 5r / min to 180~200r / min and maintained until stirring is complete;

[0024] Note: The above method achieves the refining of modified straw fibers through the synergistic effect of ultrasonic vibration frequency and stirring speed. The adjustment of the above three stages can effectively avoid the increase of ultrasonic energy consumption and the problem of solid particles re-aggregating due to excessive stirring speed, thereby further improving the refining effect.

[0025] Further, the product after magnetic stirring in step 2) is heated at 80-90℃ for 25-28 minutes for oil bath treatment. The product after oil bath treatment is centrifuged with 75-79% ethanol by mass concentration. Finally, it is dried under a vacuum of 0.08-0.09 MPa for 10-15 minutes. The centrifugation parameters are: centrifugation speed of 100-200 r / min, centrifugation times of 3-5 times.

[0026] Note: Oil bath treatment can further change the surface properties of sodium lignosulfonate, giving it better wettability and adsorption. It can also effectively improve the chemical reactivity of sodium lignosulfonate, making its reaction with NS more efficient, and further enhancing the retarding effect of additive B.

[0027] Furthermore, in step 1), the mixture is placed in a ball mill and ball milled for 20 to 30 minutes at a ball-to-material ratio of 2 to 3:1 and a ball milling speed of 150 to 200 r / min.

[0028] Note: The above parameters can reduce the particle size of the mixture, thereby further improving the dispersion performance of the mixture.

[0029] Furthermore, the particle size of the clay clinker powder is 1.2~1.6μm, and the particle size of the high-alumina clinker powder is 1.5~1.7μm;

[0030] Note: Clinker powder with the above particle size is easier to mix. Particle size larger than the above maximum particle size will reduce the porosity of the product, weaken the petrification process, and be detrimental to the sintering of the brick blank. Particle size smaller than the above minimum particle size may also affect the appearance of the product after firing, such as the appearance of air holes and deformation, thus affecting its quality.

[0031] Further, the water-reducing agent, by mass percentage, comprises 75-85% acetate, 0.1-0.15% sodium alkyl sulfonate, 0.3-0.5% sodium gluconate, and the balance being triethanolamine;

[0032] Note: Adding a small amount of sodium alkyl sulfonate to the water-reducing agent can improve the toughness and durability of the mortar; triethanolamine has excellent properties such as enhancing the strength and fluidity of concrete, reducing the volume of cement paste, and reducing porosity, shrinkage, and leakage, which can effectively enhance the fluidity of the mortar, thereby reducing the amount of mortar used and lowering the preparation cost of the mortar; the retarding effect of sodium gluconate on cement concrete further improves the performance of the mortar without affecting its strength.

[0033] This invention also provides a method for preparing fire mortar for refractory brick masonry with improved bonding strength, comprising the following steps:

[0034] S1, Ingredients

[0035] Prepare the ingredients in the following order: clay clinker powder, soft clay, high-alumina clinker powder, binder, additives, and water. Set aside.

[0036] S2, Mixed materials

[0037] S2-1. Place clay clinker powder and soft clay in a mixer and dry mix for 5-10 minutes. Add 2 / 3 of the binder and microwave irradiate it at a microwave frequency of 120-150W. Continue to dry mix for 3-5 minutes to obtain a mixture. Then spray 1 / 4 of the water and additive A into the mixture and stir for 5-10 minutes to obtain material A.

[0038] S2-2. Take 2 / 3 of material A from step S2-1 and continue to add high-alumina clinker powder and additive B. Adjust the microwave frequency to 80~100W, dry mix for 10~12 minutes, then add 1 / 4 of the water and wet mix for 12~15 minutes. Finally, take another 1 / 4 of the water to rinse the container containing additive B, and add the rinsing liquid back into the mixer and stir for 15~20 minutes to obtain material B.

[0039] S2-3. Mix the remaining material A, material B, remaining binder and the remaining water for 5-7 minutes, and then dry them to obtain the mixture.

[0040] S3, Mixing

[0041] The mixture is placed into a mixer in 2 to 4 batches, and the initial temperature is adjusted to 300 to 350°C. Then, the temperature is increased to 1100 to 1120°C at a rate of 10 to 15°C / min, and the mixing time is 1 to 2 hours. Finally, the temperature is reduced at a rate of 0.5 to 1.5°C / min until the temperature inside the mixing furnace reaches 700 to 720°C. Then, the mixture is cooled to room temperature with the furnace to obtain refractory brick mortar.

[0042] Further, in steps S2-3, the drying process is as follows: the vacuum drying oven is evacuated to a vacuum degree of 0.05~0.07MPa, and then the wet-mixed material is placed into the vacuum drying oven. The temperature of the vacuum drying oven is adjusted to 75~85℃, and the drying time is 25~30min.

[0043] Note: Vacuum drying can better remove moisture and other volatile substances from materials, improve the mixing effect of materials, and at the same time, vacuum drying can also prevent materials from being contaminated during the drying process, thereby ensuring the quality and stability of materials.

[0044] The beneficial effects of this invention are:

[0045] (1) By modifying wheat straw fiber, this invention has higher bonding strength than the binder used in the preparation process of fire clay in the prior art. At the same time, it has lower requirements for temperature conditions and still has high bonding strength at room temperature, which meets the requirements for wider use in the construction of refractory bricks.

[0046] (2) The method for preparing fire mortar for refractory brick masonry with improved bonding strength of the present invention can effectively improve the drying efficiency of materials by using microwave treatment, which facilitates dry mixing. Dry mixing followed by wet mixing can make the binder, clinker powder and soft clay fully mixed evenly, further improving the quality of fire mortar. The cooling rate of fire mortar is slowed down during the mixing process to prevent the rapid change in the volume of each crystal phase inside from causing damage to the internal structure of the binder and affecting the final bonding effect.

[0047] (3) By preparing an additive B, the present invention has a strong retarding ability, which further extends the hardening time of fire clay and can effectively prevent the fire clay from hardening before ceramic bonding and losing its original plasticity; at the same time, the fire clay prepared by using the additive B has strong fluidity and high bonding strength. Detailed Implementation

[0048] The present invention will now be described in more detail with reference to specific embodiments, so as to better demonstrate the advantages of the present invention.

[0049] Example 1

[0050] A fire mortar for improving the bonding strength of refractory bricks comprises, by weight percentage, 50% clay clinker powder, 20% soft clay, 10% high-alumina clinker powder, 11% binder, 1.5% additives, and the balance being water; the clay clinker powder has a particle size of 1.2~1.6μm, and the high-alumina clinker powder has a particle size of 1.5~1.7μm;

[0051] The binder is composed of sodium carboxymethyl cellulose, modified wheat straw fiber, and water-reducing agent in a weight ratio of 6:2.5:1;

[0052] The modified wheat straw fiber is prepared as follows: wheat straw fiber is weighed according to the weight ratio of sodium hydroxide solution to wheat straw fiber of 104:98 and soaked in sodium hydroxide solution with a mass concentration of 0.09mol / L. After standing for 6 hours, the obtained solid product is poured into an ultrasonic vibration device with a vibration frequency of 40kHz and a vibration amplitude of 1.5μm for refining treatment for 1.5 hours. During the treatment, epoxy resin is added according to the weight volume ratio of solid product to epoxy resin of 6g:50mL. Stirring is continued for 40 minutes to obtain modified wheat straw fiber.

[0053] In the preparation of modified wheat straw fiber, the stirring speed was adjusted from 150 to 200 r / min according to the vibration frequency. The adjustment was carried out in the following stages:

[0054] Phase 1: While maintaining the vibration frequency at 33kHz, the stirring speed is increased from an initial speed of 150r / min to 200r / min at a frequency of 5r / min.

[0055] Phase 2: Continue to adjust the vibration frequency to maintain it at 38kHz. At this point, the stirring speed will start to decrease from 10r / min to 160r / min and then be maintained.

[0056] Phase 3: When the vibration frequency rises to 45kHz, the stirring speed is increased from 5r / min to 190r / min and maintained until stirring is complete;

[0057] The water-reducing agent, by weight percentage, comprises 80% acetate, 0.12% sodium alkyl sulfonate, 0.4% sodium gluconate, and the balance triethanolamine;

[0058] The additive consists of additive A and additive B in a weight ratio of 2.5:1;

[0059] Additive A is composed of silicon dioxide and mica mineral fibers in equal proportions;

[0060] The preparation method of additive B is as follows:

[0061] 1) Weigh nano-silicon carbide and sodium silicate at a weight ratio of 1:1 and mix them to obtain a mixture. Then, add deionized water to the mixture at a weight-volume ratio of 13g:85mL and stir for 18min to obtain a dispersion. In step 1), put the mixture into a ball mill and ball mill it for 25min at a ball-to-material ratio of 2.5:1 and a ball milling speed of 175r / min.

[0062] 2) Weigh out 4% NS and 25% sodium lignosulfonate in the dispersion and transfer them to a magnetic stirrer. Then add the dispersion to the magnetic stirrer, adjust the magnetic stirring speed to 600 rpm, the magnetic stirring power to 25 W, and the magnetic stirring time to 6 min.

[0063] 3) The product after magnetic stirring is cured at 25°C and 30%RH for 29 days to obtain additive B.

[0064] This embodiment describes a method for preparing fire mortar for refractory brick masonry to improve bonding strength, comprising the following steps:

[0065] S1, Ingredients

[0066] Prepare the ingredients in the following order: clay clinker powder, soft clay, high-alumina clinker powder, binder, additives, and water. Set aside.

[0067] S2, Mixed materials

[0068] S2-1. Place clay clinker powder and soft clay in a mixer and dry mix for 8 minutes. Add 2 / 3 of the binder and microwave irradiate it at a microwave frequency of 135W. Continue to dry mix for 4 minutes to obtain a mixture. Then spray 1 / 4 of the water and additive A into the mixture and stir for 8 minutes to obtain material A.

[0069] S2-2. Take 2 / 3 of material A from step S2-1 and continue to add high-alumina clinker powder and additive B. Adjust the microwave frequency to 90W, dry mix for 11 minutes, then add 1 / 4 of the water and wet mix for 14 minutes. Finally, take another 1 / 4 of the water to rinse the container containing additive B, and add the rinsing liquid back into the mixer and stir for 18 minutes to obtain material B.

[0070] S2-3. Mix the remaining material A, material B, remaining binder and the remaining water for 6 minutes, and then dry them to obtain the mixture.

[0071] In steps S2-3, the drying process is as follows: the vacuum drying oven is evacuated to a vacuum degree of 0.06 MPa, and then the wet-mixed material is placed into the vacuum drying oven. The temperature of the vacuum drying oven is adjusted to 80℃ and the drying time is 28 min.

[0072] S3, Mixing

[0073] The mixture is placed in a mixer and the initial temperature is adjusted to 325℃. Then, the temperature is increased to 1110℃ at a rate of 13℃ / min and the mixing time is 1.5h. Finally, the temperature is reduced at a rate of 1℃ / min until the temperature inside the mixing furnace reaches 710℃. Then, the mixture is cooled to room temperature with the furnace to obtain refractory brick mortar.

[0074] Example 2

[0075] Unlike Example 1, a fire mortar for improving the bonding strength of refractory bricks comprises, by weight percentage, 48% clay clinker powder, 18% soft clay, 8% high-alumina clinker powder, 10% binder, 1% additives, and the balance being water.

[0076] Example 3

[0077] Unlike Example 1, a fire mortar for improving the bonding strength of refractory bricks comprises, by weight percentage, 52% clay clinker powder, 22% soft clay, 12% high-alumina clinker powder, 12% binder, 2% additives, and the balance being water.

[0078] Example 4

[0079] Unlike Example 1, the binder is composed of sodium carboxymethyl cellulose, modified wheat straw fiber, and water-reducing agent in a weight ratio of 5:2:0.5.

[0080] Example 5

[0081] Unlike Example 1, the binder is composed of sodium carboxymethyl cellulose, modified wheat straw fiber, and water-reducing agent in a weight ratio of 7:3:1.5.

[0082] Example 6

[0083] Unlike Example 1, the modified wheat straw fiber was prepared as follows: wheat straw fiber was weighed according to the weight ratio of sodium hydroxide solution to wheat straw fiber of 104:95 and soaked in sodium hydroxide solution with a mass concentration of 0.08 mol / L. After standing for 5 hours, the obtained solid product was poured into an ultrasonic vibration device with a vibration frequency of 30 kHz and a vibration amplitude of 1 μm for 1 hour for refining treatment. During the treatment, epoxy resin was added according to the weight volume ratio of solid product to epoxy resin of 5 g:45 mL. Stirring was continued for 30 minutes to obtain the modified wheat straw fiber.

[0084] Example 7

[0085] Unlike Example 1, the modified wheat straw fiber was prepared as follows: wheat straw fiber was weighed according to the weight ratio of sodium hydroxide solution to wheat straw fiber of 105:100 and soaked in sodium hydroxide solution with a mass concentration of 0.1 mol / L. After standing for 7 hours, the obtained solid product was poured into an ultrasonic vibration device with a vibration frequency of 50 kHz and a vibration amplitude of 2 μm for refining treatment for 2 hours. During the treatment, epoxy resin was added according to the weight volume ratio of solid product to epoxy resin of 7 g:55 mL. Stirring was continued for 50 minutes to obtain the modified wheat straw fiber.

[0086] Example 8

[0087] Unlike Example 1, the adjustment method is divided into the following stages:

[0088] Phase 1: While maintaining the vibration frequency at 30kHz, the stirring speed is increased from an initial speed of 150r / min to 200r / min at a frequency of 5r / min.

[0089] Phase 2: Continue to adjust the vibration frequency to maintain it at 36kHz. At this point, the stirring speed will start to decrease from 10r / min to 150r / min and then be maintained.

[0090] Phase 3: When the vibration frequency rises to 41kHz, the stirring speed is increased from 5r / min to 180r / min and maintained until stirring is complete.

[0091] Example 9

[0092] Unlike Example 1, the adjustment method is divided into the following stages:

[0093] Phase 1: While maintaining the vibration frequency at 35kHz, the stirring speed is increased from an initial speed of 150r / min to 200r / min at a frequency of 5r / min.

[0094] Phase 2: Continue to adjust the vibration frequency to maintain at 40kHz. At this point, the stirring speed will decrease from 10r / min to 170r / min and then be maintained.

[0095] Phase 3: When the vibration frequency rises to 50kHz, the stirring speed is increased from 5r / min to 200r / min and maintained until stirring is complete.

[0096] Example 10

[0097] Unlike Example 1, the water-reducing agent, by weight percentage, comprises 75% acetate, 0.1% sodium alkyl sulfonate, 0.3% sodium gluconate, and the balance triethanolamine.

[0098] Example 11

[0099] Unlike Example 1, the water-reducing agent, by weight percentage, comprises 85% acetate, 0.15% sodium alkyl sulfonate, 0.5% sodium gluconate, and the balance triethanolamine.

[0100] Example 12

[0101] Unlike Example 1, the preparation method of additive B is as follows:

[0102] 1) Weigh out nano-silicon carbide and sodium silicate at a weight ratio of 1:1 and mix them to obtain a mixture. Then add deionized water to the mixture at a weight-volume ratio of 10g:80mL and stir for 15min to obtain a dispersion.

[0103] Example 13

[0104] Unlike Example 1, the preparation method of additive B is as follows:

[0105] 1) Weigh nano-silicon carbide and sodium silicate at a weight ratio of 1:1 to obtain a mixture. Then add deionized water to the mixture at a weight-volume ratio of 15g:90mL and stir for 20min to obtain a dispersion.

[0106] Example 14

[0107] Unlike Example 1, in step 1), the mixture is placed in a ball mill and milled for 30 minutes at a ball-to-material ratio of 2:1 and a ball milling speed of 150 r / min.

[0108] Example 15

[0109] Unlike Example 1, in step 1), the mixture is placed in a ball mill and milled for 20 minutes at a ball-to-material ratio of 3:1 and a ball milling speed of 200 r / min.

[0110] Example 16

[0111] Unlike Example 1, the preparation method of additive B is as follows:

[0112] 2) Weigh out 3% NS and 20% sodium lignosulfonate of the dispersion and transfer them to a magnetic stirrer in sequence. Then add the dispersion to the magnetic stirrer, adjust the magnetic stirring speed to 500 rpm, the magnetic stirring power to 15 W, and the magnetic stirring time to 7 min.

[0113] Example 17

[0114] Unlike Example 1, the preparation method of additive B is as follows:

[0115] 2) Weigh out 5% of the NS and 30% of the sodium lignosulfonate in the dispersion and transfer them to a magnetic stirrer in sequence. Then add the dispersion to the magnetic stirrer, adjust the magnetic stirring speed to 700 rpm, the magnetic stirring power to 30 W, and the magnetic stirring time to 5 min.

[0116] Example 18

[0117] Unlike Example 1, the preparation method of additive B is as follows:

[0118] 3) The product after magnetic stirring is cured for 28 days at a temperature of 25℃ and a humidity of 30%RH to obtain additive B.

[0119] Example 19

[0120] Unlike Example 1, the preparation method of additive B is as follows:

[0121] 3) The product after magnetic stirring is cured for 30 days at a temperature of 25℃ and a humidity of 30%RH to obtain additive B.

[0122] Example 20

[0123] Unlike Example 1, in S2-1, clay clinker powder and soft clay are placed in a mixer and dry-mixed for 5 minutes. 2 / 3 of the binder is added and microwave irradiation is performed at a microwave frequency of 120W. Dry mixing is continued for 3 minutes to obtain a mixture. Then, 1 / 4 of the water and additive A are sprayed into the mixture and stirred for 5 minutes to obtain material A.

[0124] Example 21

[0125] Unlike Example 1, in S2-1, clay clinker powder and soft clay are placed in a mixer and dry-mixed for 10 minutes. 2 / 3 of the binder is added and microwave irradiation is performed at a microwave frequency of 150W. Dry mixing is continued for 5 minutes to obtain a mixture. Then, 1 / 4 of the water and additive A are sprayed into the mixture and stirred for 10 minutes to obtain material A.

[0126] Example 22

[0127] Unlike Example 1, in step S2-2, take 2 / 3 of material A from step S2-1 and continue to add high-alumina clinker powder and additive B. Adjust the microwave frequency to 80W, dry mix for 12 minutes, then add 1 / 4 of the water and wet mix for 12 minutes. Finally, take another 1 / 4 of the water to rinse the container containing additive B, and add the rinsing liquid back into the mixer and stir for 15 minutes to obtain material B.

[0128] Example 23

[0129] Unlike Example 1, in step S2-2, take 2 / 3 of material A from step S2-1 and continue to add high-alumina clinker powder and additive B. Adjust the microwave frequency to 100W, dry mix for 10 minutes, then add 1 / 4 of the water and wet mix for 15 minutes. Finally, take another 1 / 4 of the water to rinse the container containing additive B, and add the rinsing liquid back into the mixer and stir for 20 minutes to obtain material B.

[0130] Example 24

[0131] Unlike Example 1, in step S2-3, the remaining material A, material B, remaining binder, and the remaining water are wet-mixed for 5 minutes and then dried to obtain the mixture. In step S2-3, the drying method is as follows: the vacuum drying oven is evacuated to a vacuum degree of 0.07 MPa, and then the wet-mixed material is placed in the vacuum drying oven. The temperature of the vacuum drying oven is adjusted to 75°C and the drying time is 30 minutes.

[0132] Example 25

[0133] Unlike Example 1, in step S2-3, the remaining material A, material B, remaining binder, and the remaining water are wet-mixed for 7 minutes and then dried to obtain the mixture. In step S2-3, the drying method is as follows: the vacuum drying oven is evacuated to a vacuum degree of 0.07 MPa, and then the wet-mixed material is placed in the vacuum drying oven. The temperature of the vacuum drying oven is adjusted to 85°C and the drying time is 25 minutes.

[0134] Example 26

[0135] Unlike Example 1, S3, mixing

[0136] The mixture is placed in a mixer and the initial temperature is adjusted to 300℃. Then, the temperature is increased to 1100℃ at a rate of 10℃ / min and the mixing time is 2 hours. Finally, the temperature is reduced at a rate of 0.5℃ / min until the temperature inside the mixing furnace reaches 700℃. Then, the mixture is cooled to room temperature with the furnace to obtain refractory brick mortar.

[0137] Example 27

[0138] Unlike Example 1, S3, mixing

[0139] The mixture is placed in a mixer and the initial temperature is adjusted to 350℃. Then, the temperature is increased to 1120℃ at a rate of 15℃ / min and the mixing time is 1 hour. Finally, the temperature is reduced at a rate of 1.5℃ / min until the temperature inside the mixing furnace reaches 720℃. Then, the mixture is cooled to room temperature with the furnace to obtain refractory brick mortar.

[0140] Example 28

[0141] Unlike Example 1, the product after magnetic stirring in step 2) was heated at 80°C for 28 minutes and then subjected to an oil bath treatment. The product after the oil bath treatment was centrifuged with 75% ethanol and finally dried under a vacuum of 0.08 MPa for 15 minutes. The centrifugation parameters were: centrifugation speed of 100 r / min and centrifugation times of 5.

[0142] Example 29

[0143] Unlike Example 1, the product after magnetic stirring in step 2) was heated at 85°C for 27 min and then subjected to an oil bath treatment. The product after the oil bath treatment was centrifuged with 77% ethanol and finally dried under a vacuum of 0.085 MPa for 13 min. The centrifugation parameters were: centrifugation speed of 150 r / min and centrifugation times of 4.

[0144] Example 30

[0145] Unlike Example 1, the product after magnetic stirring in step 2) was heated at 90°C for 25 minutes and then subjected to an oil bath treatment. The product after the oil bath treatment was centrifuged with 79% ethanol and finally dried under a vacuum of 0.09 MPa for 10 minutes. The centrifugation parameters were: centrifugation speed of 200 r / min and centrifugation times of 3.

[0146] Experimental Example

[0147] For the fire clay prepared in each embodiment, five samples were taken from each embodiment to test the bonding strength of the fire clay. The average value of the test results of the five samples in each embodiment was taken as the test result of that embodiment. The specific investigation is as follows:

[0148] 1. Investigate the effects of raw material ratio and particle size on the bonding strength of fire clay.

[0149] Table 1. Bond strength (MPa) of the fire putty prepared in Examples 1-3 and Comparative Examples 1-2.

[0150]

[0151] Comparative Example 1: Unlike Example 1, a fire mortar for improving the bonding strength of refractory bricks comprises, by weight percentage, 50% clay clinker powder, 20% soft clay, 13% high-alumina clinker powder, 11% binder, 1.5% additives, and the balance being water.

[0152] Comparative Example 2: Unlike Example 1, the particle size of the clay clinker powder is 1.7 μm and the particle size of the high-alumina clinker powder is 1.9 μm.

[0153] Conclusion: Comparison of the data from Examples 1-3 and Comparative Example 1 in Table 1 shows that adding an appropriate amount of high-alumina clinker powder can improve the bonding strength of fire clay. However, if the amount added exceeds the range of this method, it will cause difficulty in sintering, thereby reducing the bonding strength. Comparison of the data from Examples 1-3 and Comparative Example 2 in Table 1 shows that if the particle size of the clinker powder is larger than the upper limit of the range of this method, it will cause a decrease in the bonding strength of the fire clay. This is because excessively large particle size can easily lead to a decrease in the porosity of the fire clay, thereby reducing the bonding strength. Therefore, Example 1 is the optimal solution.

[0154] 2. Investigate the effect of binder composition on the bonding strength of pyrite.

[0155] Table 2. Bond strength (MPa) of the fire putty prepared in Examples 1, 4-11, and Comparative Examples 3-5.

[0156]

[0157] Comparative Example 3: Unlike Example 1, the adhesive is composed of sodium carboxymethyl cellulose, wheat straw fiber and water-reducing agent in a weight ratio of 6:2.5:1.

[0158] Comparative Example 4: Unlike Example 1, in the preparation method of modified wheat straw fiber, epoxy resin is not added to the product after the refining treatment.

[0159] Comparative Example 5: Unlike Example 1, the water-reducing agent, by mass percentage, comprises 80% acetate, 0.12% sodium alkyl sulfonate, and the balance triethanolamine.

[0160] Conclusion: As can be seen from the comparison of the data of Examples 1, 4-5 and Control Example 3 in Table 2, the bonding strength of the fire clay prepared without modification of wheat straw fiber is significantly reduced. This is because although wheat straw fiber has a certain high aspect ratio and porous structure, which can provide better physical support and reinforcement, and can play a certain role in improving the bonding strength of sodium carboxymethyl cellulose, its filling effect is still not as good as that of modified wheat straw fiber.

[0161] As can be seen from the data comparison of Examples 1, 6-7 and Comparative Example 4 in Table 2, the bonding performance of fire putty will also be reduced if epoxy resin is not added to the refined product. This is because the addition of epoxy resin can be highly compatible with the modified wheat straw fiber, further improving the overall filling performance of the adhesive, fully filling the micropores and defects on the surface of the bonded object, forming a dense and smooth bonding interface, thereby improving its bonding effect.

[0162] As can be seen from the data comparison of Examples 1, 10-11 and Comparative Example 4 in Table 2, the lack of sodium gluconate weakens the retarding effect of the water-reducing agent, thereby reducing the bonding effect of the fire clay.

[0163] 3. Investigate the effect of binder composition on the bonding strength of pyroxide.

[0164] Table 3. Bond strength (MPa) of the fire putty prepared in Examples 1, 12-19, 28-30 and Control Examples 6-7.

[0165]

[0166] Comparative Example 6: Unlike Example 1, the ball milling step is missing.

[0167] Comparative Example 7: Unlike Example 1, 2) Sodium lignosulfonate accounting for 25% of the dispersion was weighed and transferred to a magnetic stirrer in sequence. Then, the dispersion was added to the magnetic stirrer, and the magnetic stirring speed was adjusted to 600 rpm, the magnetic stirring power was 25 W, and the magnetic stirring time was 6 min.

[0168] Conclusions: Data from Examples 1, 14-15, and Comparative Example 6 in Table 3 show that the lack of ball milling resulted in uneven particle size distribution in the mixture, further reducing its dispersion performance and weakening the effect of NS on improving the bonding strength of the fire clay. Data from Examples 1, 16-17, and Comparative Example 7 show that the lack of NS addition weakened the uniformity of the transition zone at the bonding interface of the fire clay, thus reducing its bonding strength. Data from Examples 28-30 show that oil bath treatment of the magnetically stirred product further improved the wettability and adsorption of sodium lignosulfonate, allowing NS to better act on sodium lignosulfonate, further enhancing the retarding effect of additive B, and further improving the bonding strength of the fire clay. Therefore, Example 29 is the optimal solution.

[0169] 4. Investigate the effect of preparation method on the bonding strength of fire clay.

[0170] Table 4. Bond strength (MPa) of the fire putty prepared in Examples 1, 20-27 and Control Example 8.

[0171]

[0172] Comparative Example 8: Unlike Example 1, microwave irradiation treatment is not performed in step S2-1.

[0173] Comparative Example 9: Unlike Example 1, no drying process is performed in steps S2-3.

[0174] Conclusion: Comparison of the data from Examples 1, 20-21 and Comparative Example 8 in Table 4 shows that the bonding strength of fire clay prepared without microwave irradiation treatment during material mixing tends to decrease. This is because microwave treatment can effectively improve the drying efficiency of materials, making dry mixing easier. Dry mixing followed by wet mixing allows the binder to be fully and evenly mixed with the clinker powder and soft clay, thus enabling the binder to act better on the materials and thereby improving the bonding strength of the fire clay.

[0175] Comparing the data of Examples 1, 24-25 and Comparative Example 9 in Table 4, it can be seen that the lack of drying treatment will also lead to a decrease in the bonding strength of fire clay. The main reason is that vacuum drying can effectively remove moisture and other volatile substances from the material, thereby improving the purity of fire clay and further improving the bonding strength of fire clay. Based on the data in Tables 1-4, Example 29 is the optimal solution.

Claims

1. A type of fire mortar for refractory brick masonry that improves bonding strength, characterized in that, By weight percentage, it includes 48-52% clay clinker powder, 18-22% soft clay, 8-12% high-alumina clinker powder, 10-12% binder, 1-2% additives, and the balance being water. The binder is composed of sodium carboxymethyl cellulose, modified wheat straw fiber, and water-reducing agent in a weight ratio of 5~7:2~3:0.5~1.5; The modified wheat straw fiber is prepared as follows: Weigh wheat straw fiber according to the weight ratio of sodium hydroxide solution to wheat straw fiber of 104~105:95~100 and soak it in sodium hydroxide solution with a mass concentration of 0.08~0.1mol / L. Let it stand for 5~7h. Then pour the obtained solid product into an ultrasonic vibration device with a vibration frequency of 30~50kHz and a vibration amplitude of 1~2μm for refining treatment for 1~2h. During the treatment, epoxy resin is added according to the weight volume ratio of solid product to epoxy resin of 5~7g:45~55mL. Stir for 30~50min to obtain modified wheat straw fiber. In the preparation process of modified wheat straw fiber, the stirring speed is adjusted from 150 to 200 r / min according to the vibration frequency. The adjustment method is divided into the following stages: Phase 1: While maintaining the vibration frequency at 30~35kHz, the stirring speed is increased from an initial speed of 150r / min to 200r / min at a frequency of 5r / min. Phase 2: Continue to adjust the vibration frequency to maintain it at 36~40kHz. At this time, the stirring speed will start to decrease from 10r / min to 150~170r / min and then be maintained. Phase 3: When the vibration frequency rises to 41~50kHz, the stirring speed is increased from 5r / min to 180~200r / min and maintained until stirring is complete; The additive is composed of additive A and additive B in a weight ratio of 2 to 3:1; The additive A is composed of silicon dioxide and mica mineral fibers or talc mineral fibers in equal weight ratios. The preparation method of additive B is as follows: 1) Weigh out nano-silicon carbide and sodium silicate at a weight ratio of 1:1 and mix them to obtain a mixture. Then, add deionized water to the mixture at a weight-to-volume ratio of 10~15g:80~90mL and stir for 15~20min to obtain a dispersion. 2) Weigh out 3-5 wt% of NS and 20-30 wt% of sodium lignosulfonate from the dispersion and transfer them sequentially to a magnetic stirrer. Then add the dispersion to the magnetic stirrer, adjust the magnetic stirring speed to 500-700 rpm, the magnetic stirring power to 15-30 W, and the magnetic stirring time to 5-7 min. Place the product after magnetic stirring in step 2) into an oil bath at 80-90℃ for 25-28 min. Centrifuge the product after oil bath treatment with 75-79% ethanol. Finally, dry it under a vacuum of 0.08-0.09 MPa for 10-15 min. The centrifugation parameters are: centrifugation speed of 100-200 r / min and centrifugation times of 3-5. 3) The product after magnetic stirring is cured for 28 to 30 days to obtain additive B.

2. The fire mortar for improving the bonding strength of refractory brick masonry as described in claim 1, characterized in that, The environment for the maintenance treatment is: temperature 24~26℃, humidity ≤30%RH.

3. The fire mortar for improving the bonding strength of refractory brick masonry as described in claim 1, characterized in that, In step 1), the mixture is placed in a ball mill and milled for 20 to 30 minutes at a ball-to-material ratio of 2 to 3:1 and a ball milling speed of 150 to 200 r / min.

4. The fire mortar for improving the bonding strength of refractory brick masonry as described in claim 1, characterized in that, The clay clinker powder has a particle size of 1.2~1.6μm, and the high-alumina clinker powder has a particle size of 1.5~1.7μm.

5. The fire mortar for improving the bonding strength of refractory brick masonry as described in claim 1, characterized in that, The water-reducing agent, by mass percentage, comprises 75-85% acetate, 0.1-0.15% sodium alkyl sulfonate, 0.3-0.5% sodium gluconate, and the balance being triethanolamine.

6. A method for preparing fire mortar for refractory brick masonry with improved bonding strength, used to prepare the fire mortar for refractory brick masonry with improved bonding strength as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1, Ingredients Prepare the ingredients in the following order: clay clinker powder, soft clay, high-alumina clinker powder, binder, additives, and water. Set aside. S2, Mixed materials S2-1. Place clay clinker powder and soft clay in a mixer and dry mix for 5-10 minutes. Add 2 / 3 of the binder and microwave irradiate it at a microwave frequency of 120-150W. Continue to dry mix for 3-5 minutes to obtain a mixture. Then spray 1 / 4 of the water and additive A into the mixture and stir for 5-10 minutes to obtain material A. S2-2. Take 2 / 3 of material A from step S2-1 and continue to add high-alumina clinker powder and additive B. Adjust the microwave frequency to 80~100W, dry mix for 10~12 minutes, then add 1 / 4 of the water, wet mix for 12~15 minutes, and finally take another 1 / 4 of the water to rinse the container containing additive B. Add the rinsing liquid back into the mixer and stir for 15~20 minutes to obtain material B. S2-3. Mix the remaining material A, material B, remaining binder and the remaining water for 5-7 minutes, and then dry them to obtain the mixture. S3, Mixing The mixture is placed into a mixer in 2 to 4 batches, and the initial temperature is adjusted to 300 to 350°C. Then, the temperature is increased to 1100 to 1120°C at a rate of 10 to 15°C / min, and the mixing time is 1 to 2 hours. Finally, the temperature is reduced at a rate of 0.5 to 1.5°C / min until the temperature inside the mixing furnace reaches 700 to 720°C. The mixture is then cooled to room temperature with the furnace to obtain refractory brick mortar.

7. The method for preparing refractory brick masonry mortar with improved bonding strength as described in claim 6, characterized in that, In steps S2-3, the drying process is as follows: the vacuum drying oven is evacuated to a vacuum degree of 0.05~0.07MPa, and then the wet-mixed material is placed into the vacuum drying oven. The temperature of the vacuum drying oven is adjusted to 75~85℃, and the drying time is 25~30min.

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