A wet siliceous slurry, its preparation and use

Abstract

The application discloses a wet siliceous mud, a preparation method and application thereof, and belongs to the technical field of mud. The wet siliceous mud comprises the following components in mass fraction: 30-52% of silica sand, 7-16% of calcined quartz, 6-7% of silica brick fine powder, 4-6% of silica micro powder, 1-2% of dextrin, 1-2% of sodium dihydrogen phosphate, 0.5% of quaternary ammonium salt preservative, 0.5-1% of BIT and 25-30% of water, and the sum of the mass of the components is 100%. The siliceous mud has excellent performance and long holding time.

Description

Technical Field

[0001] This invention relates to the field of high-temperature new materials technology, specifically to a wet silica slurry, its preparation method and application. The wet silica slurry is a bonding material suitable for the construction of various high-temperature kilns such as coke ovens, glass kilns, and hot blast stoves. Background Technology

[0002] Slurry is a crucial bonding material in the construction of high-temperature kilns, and its performance directly determines the quality and service life of the kiln lining. With advancements in high-temperature industrial melting and combustion technologies, the service life of traditional silica refractories has significantly decreased. To address this, numerous new types of silica bricks with high purity, high performance, novel properties, and applications have been developed, greatly improving their application results. However, the matching high-performance slurry still presents challenges.

[0003] Traditional siliceous mud has the following problems:

[0004] (1) Human factors may cause the amount of water added to be too large or too small, resulting in the mortar joint thickness not being guaranteed during masonry.

[0005] (2) The lack of uniformity in mixing equipment at the construction site can lead to uneven mixing of mud.

[0006] (3) If the mixed mud is not used up during the shift or is not stored properly, it may cause the mud to become ineffective and result in waste.

[0007] (4) The mud will cause secondary dust pollution during mixing, which is not good for the environment.

[0008] (5) Poor adhesion and insufficient shelf life. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a wet siliceous mud, its preparation method, and its application. This siliceous mud not only has excellent performance but also a long retention time.

[0010] To achieve the above objectives, the specific solution adopted by the present invention is as follows:

[0011] A wet siliceous mud comprising the following components by mass fraction:

[0012]

[0013] Furthermore, the silica sand contains ≥97.5% SiO2, with particles ranging from 1 to 0.5 mm accounting for 5 to 15% of the total mass of the silica sand, particles ranging from 0.5 to 0.074 mm accounting for 15 to 30% of the total mass of the silica sand, and particles with a diameter <0.074 mm accounting for 55 to 80% of the total mass of the silica sand.

[0014] Furthermore, the SiO2 content in the calcined quartz is ≥99%, and particles with a particle size range of <0.074mm account for 85-95% of the total mass of the calcined quartz.

[0015] Furthermore, in the silica brick fine powder, particles with a particle size range of <0.074 mm account for 85-95% of the total mass of the silica brick fine powder.

[0016] Furthermore, in the silicon micro powder, particles with a diameter range of <5μm account for 3-5% of the total mass of the silicon micro powder.

[0017] Furthermore, quaternary ammonium salt preservatives include any one of double-chain quaternary ammonium salts, single-chain quaternary ammonium salts, aliphatic quaternary ammonium salts, or aromatic quaternary ammonium salts.

[0018] A method for preparing wet siliceous mud mainly includes the following steps:

[0019] Step 1: Weigh each raw material according to the mass fractions mentioned above;

[0020] Step 2: Add water and quaternary ammonium salt preservatives to a mixer and stir to obtain a mixed liquid;

[0021] Step 3: Mix silica sand, calcined quartz, silica brick powder, silica micro powder, dextrin, and sodium dihydrogen phosphate evenly to obtain a mixture. Add the mixture and the liquid mixture obtained in Step 2 to a mixer and stir at low speed first and then at high speed to obtain the original mixed slurry. Step 4: Add BIT to the original mixed slurry and stir evenly to obtain the intermediate mixed slurry.

[0022] Step 5: Degas the intermediate mixed slurry. After degassing, the final silica slurry is obtained. Then, vacuum seal the silica slurry.

[0023] The application of the above-mentioned wet siliceous slurry in high-temperature kilns.

[0024] The functions of each component in the wet siliceous mud of this invention are as follows:

[0025] Silica sand can improve the flexural strength of drilling mud. It has a large specific surface area and high activity, and when mixed with water, it possesses certain adhesiveness and plasticity, thus improving the fluidity, workability, and bond strength of the mud. However, as the amount of silica sand added increases, the bonding time during mud application prolongs; therefore, the amount of silica sand added should not be too large.

[0026] Sodium dihydrogen phosphate can extend the shelf life of mud and prevent the growth of microorganisms. Moreover, under certain conditions, it can also promote sintering.

[0027] The functions of silica powder are as follows: Firstly, with a particle size not exceeding 5μm, silica powder has a large specific surface area, providing more contact area with water and particles in the mud, thereby enhancing the binding and adhesion of the mud and improving its strength. Secondly, silica powder can fill micropores, cracks, and voids in the mud, increasing its density and compactness, thus improving its strength. Thirdly, silica powder can increase the viscosity and rheological properties of the mud, preventing the settling and sedimentation of solid particles, thereby improving the low-temperature and medium-temperature strength of the mud.

[0028] Calcined quartz transforms into low-density variants (tridymite and cristobalite) during firing without significantly reducing its refractoriness. It also prevents the formation of slurry and silica bricks that would otherwise detach due to rapid expansion at high temperatures.

[0029] Dextrin enables the components in the mud to adhere to each other during the mixing process, thereby enhancing the mud's cohesiveness, effectively preventing sedimentation and stratification during storage, extending the mud's shelf life, and improving the mud's low-temperature bonding strength.

[0030] Introducing fine silica brick powder into the slurry not only ensures the bonding strength with the coke oven and makes the thermal expansion rate of the slurry basically consistent with that of the silica brick, but also introduces some CaO and FeO due to the addition of waste silica brick. This accelerates the transformation of some quartz in the siliceous slurry into low-density variants (tridymite and cristobalite) during firing without significantly reducing its refractoriness. It also prevents the slurry from falling off from the silica brick due to rapid expansion at high temperatures.

[0031] BIT has excellent antibacterial, antialgae, and antifungal properties.

[0032] Quaternary ammonium salt preservatives can inhibit the growth of bacteria, fungi and other microorganisms.

[0033] Beneficial effects:

[0034] (1) The formulation of the wet silica mud of the present invention is carefully designed and selected, and the proportions of various materials are scientifically balanced to ensure that the mud has good workability, bonding strength and durability. This formulation can adapt to various different use environments and temperature conditions, ensuring the stability of the mud during long-term storage and construction. The preparation of the mud requires a fine process of mixing, stirring and molding to ensure the uniformity and stability of the mud. This fine preparation process can guarantee the quality of the mud during storage and construction, ensuring the stability and reliability of its performance.

[0035] (2) The components in this invention can produce synergistic or enhanced effects, ensuring the performance of the mud while extending its shelf life. Among them, silica sand is used as the main material in the powder, which can ensure the high-temperature performance of the mud. When used in combination with calcined quartz, silica brick fine powder and silica micro powder, it can further improve the mud's resistance to high temperature, impermeability and erosion.

[0036] (3) By controlling different particle size distributions, the present invention can make them as close to compact packing as possible, which can effectively improve the density of wet siliceous mud after hardening.

[0037] (4) In preparing wet siliceous mud, the present invention first mixes water with quaternary ammonium salt preservatives to enhance the solvent's ability to inhibit bacteria and fungi. After obtaining the original mixed mud, BIT is added to the original mixed mud to inhibit the growth of bacteria in the mud and increase the storage time of the mud.

[0038] (5) The wet silica slurry prepared by the present invention can be used as needed without the need for operators to stir or add other substances. This not only avoids the problem of uneven mixing on the construction site, but also avoids the inability to guarantee the thickness of the mortar joints during masonry due to the inability to control the amount of water added. It also avoids the waste caused by the slurry not being used up during the shift. Detailed Implementation

[0039] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0040] This invention discloses a wet siliceous slurry comprising the following components by mass fraction: 30-52% silica sand; 7-16% calcined quartz; 6-7% fine silica brick powder; 4-6% silica micropowder; 1-2% dextrin; 1-2% sodium dihydrogen phosphate; 0.5% quaternary ammonium salt preservative; 0.5-1% BIT; and 25-30% water; the sum of the mass of each component is 100%.

[0041] The silica sand contains ≥97.5% SiO2, with particles ranging from 1 to 0.5 mm accounting for 5 to 15% of the total mass of the silica sand, particles ranging from 0.5 to 0.074 mm accounting for 15 to 30% of the total mass of the silica sand, and particles with a diameter <0.074 mm accounting for 55 to 80% of the total mass of the silica sand.

[0042] The calcined quartz contains ≥99% SiO2, and particles with a diameter range of <0.074mm account for 85-95% of the total mass of the calcined quartz.

[0043] In the silica brick fine powder, particles with a diameter range of <0.074 mm account for 85-95% of the total mass of the silica brick fine powder.

[0044] In the silicon micro powder, particles with a diameter range of <5μm account for 3 to 5% of the total mass of the silicon micro powder.

[0045] Specifically, quaternary ammonium salt preservatives include any one of double-chain quaternary ammonium salts, single-chain quaternary ammonium salts, aliphatic quaternary ammonium salts, and aromatic quaternary ammonium salts.

[0046] This invention discloses a method for preparing wet siliceous mud, which mainly includes the following steps:

[0047] Step 1: Weigh each raw material according to the mass fractions mentioned above. When mixing the ingredients, ensure that the raw materials are dry and free of impurities, and mix them according to the proportions. It is recommended to use sealed containers to store the raw materials to avoid moisture or contamination.

[0048] Step 2: Add water and quaternary ammonium salt preservative to a mixer and stir for 5-10 minutes to obtain a mixed liquid;

[0049] Step 3: Mix silica sand, calcined quartz, silica brick powder, silica micro powder, dextrin, and sodium dihydrogen phosphate evenly to obtain a mixture. Add the mixture and the liquid mixture obtained in Step 2 to a mixer and stir. First, stir at a stirring speed of 25-100 r / min, and gradually increase the stirring speed to 100-300 r / min. The total stirring time is 5-10 minutes to obtain a mixed slurry.

[0050] Step 4: Add BIT to the mixed mud and stir for 5-10 minutes;

[0051] Step 5: Degas the mud for 20-30 minutes;

[0052] Step Six: After production is complete, the mud is packaged in sealed containers to ensure its quality and stability. During packaging, care must be taken to avoid contaminating or damaging the mud.

[0053] The method for applying the wet siliceous slurry in a high-temperature kiln according to the present invention mainly includes the following steps:

[0054] (1) Clean and sanitize the surfaces that need to be repaired or joined, ensuring that the surfaces are free of dust and grease;

[0055] (2) Use a scraper to evenly apply the wet silica slurry to the surface that needs to be repaired or joined, with a thickness of 3-8mm. During construction, ensure that the coating thickness is uniform to avoid uneven thermal stress.

[0056] (3) After application, let it stand at room temperature for a period of time until the repaired or connected parts are dry and cured. Then, heat the kiln at high temperature to dry it to achieve the best performance of the silica slurry.

[0057] The wet siliceous mud of the present invention will be described in detail below with reference to specific embodiments.

[0058] Example 1

[0059] This invention discloses a wet siliceous slurry comprising the following components by mass fraction: 52% silica sand, 7% calcined quartz, 6% silica brick powder, 4% silica micro powder, 2% dextrin, 2% sodium dihydrogen phosphate, 0.5% single-chain quaternary ammonium salt, 0.5% BIT, and 26% water.

[0060] The silica sand contains ≥97.5% SiO2, with particles ranging from 1 to 0.5 mm accounting for 15% of the total mass, particles ranging from 0.5 to 0.074 mm accounting for 30% of the total mass, and particles with a diameter <0.074 mm accounting for 55% of the total mass.

[0061] The calcined quartz contains ≥99% SiO2, and particles with a diameter range of <0.074mm account for 95% of the total mass of the calcined quartz.

[0062] In the silica brick fine powder, particles with a particle size range of <0.074 mm account for 90% of the total mass of the silica brick fine powder.

[0063] In the silicon micro powder, particles with a diameter range of <5μm account for 5% of the total mass of the silicon micro powder.

[0064] This invention discloses a method for preparing wet siliceous mud, which mainly includes the following steps:

[0065] Step 1: Weigh each raw material according to the mass fractions mentioned above;

[0066] Step 2: Add water and quaternary ammonium salt preservative to a mixer and stir for 5 minutes to obtain a mixed liquid;

[0067] Step 3: Mix silica sand, calcined quartz, silica brick powder, silica micro powder, dextrin, and sodium dihydrogen phosphate evenly to obtain a mixture. Add the mixture and the liquid mixture obtained in Step 2 to a mixer and stir. First stir at a stirring speed of 25 r / min, and gradually increase to 100 r / min. The total stirring time is 5 minutes to obtain a mixed slurry.

[0068] Step 4: Add BIT to the mixed mud and stir for 10 minutes;

[0069] Step 5: Degas the mud for 20 minutes;

[0070] Step 6: After production is completed, the mud is packaged in sealed containers.

[0071] Example 2

[0072] The only difference between Comparative Example 2 and Example 1 is the composition of the slurry: 45% silica sand, 10% calcined quartz, 6.5% silica brick powder, 5% silica fume, 1% dextrin, 1.5% sodium dihydrogen phosphate, 0.5% double-chain quaternary ammonium salt, 0.8% BIT, and 29.7% water.

[0073] Example 3

[0074] The only difference between Comparative Example 2 and Example 1 is the composition of the slurry: 50% silica sand, 10% calcined quartz, 6% silica brick powder, 4% silica ultrafine particles, 1% dextrin, 1% sodium dihydrogen phosphate, 0.5% double-chain quaternary ammonium salt, 1% BIT, and 26.5% water.

[0075] Comparative Example 1

[0076] The only difference between Comparative Example 2 and Example 1 is that it does not contain BIT.

[0077] Comparative Example 2

[0078] The only difference between Comparative Example 2 and Example 1 is that it does not contain BIT and single-chain quaternary ammonium salts.

[0079] Composition and performance analysis

[0080]

[0081]

[0082] As shown in Table 1, the SiO2 content in the mortars prepared in Examples 1-3 and Comparative Examples 1-2 is not less than 95%. SiO2 is the main component of siliceous slurry, and the higher the SiO2 content, the higher the refractoriness and load softening temperature of the siliceous slurry. The mortars prepared in Examples 1-3 generally have a shelf life of more than 9 months, while the mortars prepared in Comparative Examples 1-2 have a shelf life of no more than 1 month.

[0083] The silica slurry prepared by this invention is suitable for thermal equipment such as high-temperature kilns (e.g., large coke ovens, glass kilns, hot blast stoves). Compared with silica fire clay, it is thick and pasty after stirring, loses water slowly, is easy to build, and produces full brick joints.

[0084] The wet silica slurry was bonded to silica bricks and sintered in a tunnel kiln (at 1420°C) and an electric kiln (at 1190°C), respectively. After sintering, the silica slurry and silica bricks were firmly bonded, and no separation of silica bricks and silica slurry occurred. This indicates that the silica slurry prepared by this invention meets the construction performance requirements for coke oven masonry, and the thickness of the mortar joints meets the masonry standards.

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention in any way. All equivalent transformations or modifications made in accordance with the essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A wet siliceous mud, characterized in that, Components containing the following mass fractions: Silica sand 30~52%; Calcined quartz 7-16%; 6-7% silica brick fine powder; 4-6% silica powder; Dextrin 1-2%; Sodium dihydrogen phosphate 1-2%; Quaternary ammonium salt preservatives: 0.5%; BIT 0.5~1%; Water content: 25-30%; The sum of the masses of all components is 100%. The preparation method of this wet siliceous mud mainly includes the following steps: Step 1: Weigh each raw material according to the mass fractions mentioned above; Step 2: Add water and quaternary ammonium salt preservatives to a mixer and stir to obtain a mixed liquid; Step 3: Mix silica sand, calcined quartz, silica brick powder, silica micro powder, dextrin, and sodium dihydrogen phosphate evenly to obtain a mixture. Add the mixture and the liquid mixture obtained in Step 2 to a mixer and stir at low speed first and then at high speed to obtain the original mixed slurry. Step 4: Add BIT to the original mixed mud and stir well to obtain intermediate mixed mud; Step 5: Degas the intermediate mixed slurry. After degassing, the final silica slurry is obtained. Then, vacuum seal the silica slurry.

2. The wet siliceous mud according to claim 1, characterized in that: The silica sand contains ≥97.5% SiO2, with particles ranging from 1 to 0.5 mm accounting for 5 to 15% of the total mass of the silica sand, particles ranging from 0.5 to 0.074 mm accounting for 15 to 30% of the total mass of the silica sand, and particles ranging from <0.074 mm accounting for 55 to 80% of the total mass of the silica sand.

3. The wet siliceous mud according to claim 1, characterized in that: The calcined quartz contains ≥99% SiO2, and particles with a diameter range of <0.074mm account for 85-95% of the total mass of the calcined quartz.

4. The wet siliceous mud according to claim 1, characterized in that: In the silica brick fine powder, particles with a particle size range of <0.074mm account for 85-95% of the total mass of the silica brick fine powder.

5. The wet siliceous mud according to claim 1, characterized in that: In the silicon micro powder, particles with a diameter range of <5μm account for 3~5% of the total mass of the silicon micro powder.

6. The wet siliceous mud according to claim 1, characterized in that: Quaternary ammonium salt preservatives include any one of double-chain quaternary ammonium salts, single-chain quaternary ammonium salts, aliphatic quaternary ammonium salts, or aromatic quaternary ammonium salts.

7. The application of the wet siliceous slurry according to any one of claims 1-6 in a high-temperature kiln.

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