Silica sol combined with tertiary air tube castable and its preparation method

Abstract

The application discloses a preparation method of silica sol combined with three-stage air pipe castable, and specifically comprises the following steps: dry mixing fused magnesite, modified white corundum, zirconia mullite, magnesium-aluminum spinel and porcelain powder to obtain dry materials; adding silica sol into the dry materials, mixing to obtain intermediate materials; adding silane coupling agent into the intermediate materials, mixing to obtain silica sol combined with three-stage air pipe castable; and the amount of each component of the silica sol combined with three-stage air pipe castable is as follows: 20-50 wt% of fused magnesite, 10-40 wt% of modified white corundum, 10-15 wt% of zirconia mullite, 10-20 wt% of magnesium-aluminum spinel, 3-5 wt% of porcelain powder, 5-15 wt% of silica sol and 0.2-4 wt% of silane coupling agent. The castable of the application solves the problems of quick solidification and poor fluidity of magnesia castable by means of suitable particle grading and addition of silica sol, and good construction performance of the castable is obtained, and the castable has excellent wear resistance, corrosion resistance and thermal shock resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of refractory castable, in particular to a silica sol combined tertiary air duct castable and a preparation method thereof. BACKGROUND

[0002] The tertiary air duct part is directly subjected to serious material erosion for a long time due to high temperature, large temperature change, high wind speed in the duct and a large amount of fine clinker particles in the hot gas flow, resulting in frequent damage and easy falling off, and the service life is generally short. At present, the construction cycle is generally required to be relatively strict, and the construction cycle is required to be short to quickly put into production and use, which puts higher requirements on the performance of the tertiary air duct. The existing castable generally has the disadvantages of poor wear resistance, poor high-temperature resistance and poor thermal shock resistance, and the service life is generally very short, and even the castable is basically damaged in a few months, which cannot meet the market demand.

[0003] A large number of researches have been carried out on the tertiary air duct castable erosion resistance improvement technology.

[0004] For example, “a high-strength wear-resistant and erosion-resistant castable” (CN201510801835.1) uses sub-white corundum as high-strength aggregate, introduces mineral admixture and additive, improves filling density through multi-proportioning, reduces porosity, and improves erosion resistance, but the dense structure reduces thermal shock resistance.

[0005] For example, “a wear-resistant castable for cement kiln tertiary air duct elbow” (CN201210314369.0) uses brown corundum as aggregate, adds white corundum powder to fill between the aggregates to ensure the overall density, and adds silicon carbide to improve the thermal shock resistance of the castable, and the protective film formed at high temperature can also improve the erosion resistance, but the introduction of excessive silicon carbide will form more liquid phase on the surface of the castable at high temperature, reducing the wear resistance.

[0006] For example, “a castable for cement kiln tertiary air duct” (CN201510800423.6) uses fused magnesia as aggregate, adds corundum and magnesium-aluminum spinel, and uses a matrix material composed of magnesia powder and other materials, and uses fiber additive to improve the integrity of the castable, thereby improving the wear resistance, corrosion resistance and erosion resistance of the castable, but the effect of this method is still not significant, it is difficult to meet the requirements, and the production efficiency is difficult to improve.

[0007] In summary, the tertiary air duct castable in the prior art cannot effectively balance excellent wear resistance, erosion resistance and thermal shock resistance. SUMMARY

[0008] The application aims to provide a silica sol combined tertiary air pipe castable and a preparation method thereof.

[0009] To achieve the above-mentioned purpose, the application provides the following technical scheme.

[0010] The application discloses a preparation method of a silica sol combined tertiary air pipe castable, and specifically comprises the following steps:

[0011] S1, dry-mixing fused magnesia, modified white corundum, zirconia mullite, magnesium aluminate spinel and porcelain powder to obtain dry materials;

[0012] S2, adding silica sol into the dry materials of step S1 and mixing to obtain intermediate materials;

[0013] S3, adding a silane coupling agent into the intermediate materials of step S2 and mixing to obtain the silica sol combined tertiary air pipe castable.

[0014] The amounts of the components of the silica sol combined tertiary air pipe castable are as follows: 20-50wt% of fused magnesia, 10-40wt% of modified white corundum, 10-15wt% of zirconia mullite, 10-20wt% of magnesium aluminate spinel, 3-5wt% of porcelain powder, 5-15wt% of silica sol and 0.2-4wt% of the silane coupling agent.

[0015] Preferably, the content of MgO in the fused magnesia is not less than 95%.

[0016] Preferably, in the fused magnesia, the proportion of particles with a particle size of 6-10mm is 5-20wt%, the proportion of particles with a particle size of 3-6mm is 35-70wt%, and the proportion of particles with a particle size of 1-3mm is 25-50wt%.

[0017] Preferably, in the modified white corundum, the proportion of particles with a particle size of 5-8mm is 5-15wt%, the proportion of particles with a particle size of 3-5mm is 44-65wt%, and the proportion of particles with a particle size of 1-3mm is 25-45wt%.

[0018] Preferably, the content of ZrO2 in the zirconia mullite is not less than 40wt%, and the content of SiO2 is not less than 45wt%.

[0019] Preferably, the content of AlF3 in the porcelain powder is not less than 60wt%, and the content of SiO2 is not less than 10wt%.

[0020] Preferably, the mixing time in step S2 is 1 to 3 minutes; the mixing time in step S3 is 1 to 3 minutes.

[0021] A silica sol-bonded tertiary air duct casting material is prepared by the above-mentioned method for preparing a silica sol-bonded tertiary air duct casting material.

[0022] The beneficial effects of this invention are:

[0023] (1) By using appropriate particle size distribution and adding silica sol, the problem of rapid solidification and poor fluidity of magnesium castables has been solved, and good construction performance of castables has been obtained.

[0024] (2) Silica sol is a polysilicic acid dispersion system with particle sizes ranging from a few nanometers to tens of nanometers. When silica sol is mixed with white corundum micro powder, colloidal particles can be adsorbed on the particle surface to form a monolayer saturated distribution and fill the gaps between particles. Therefore, it has good dispersibility and permeability. At the same time, silica sol covers the solid surface to form a stable silica sol film, so the castable has good erosion resistance and thermal shock resistance.

[0025] (3) Porcelain powder is used to soften and deform the glass matrix to inhibit the generation of cracks through vitrification. It also has a dense glaze layer to inhibit the penetration of reactive substances into the deep part. The addition of porcelain powder not only ensures that the castable has high initial strength and density, but also improves the strength of the castable and ensures that the material forms a fine capillary structure, thereby improving the corrosion resistance.

[0026] (4) A silica sol-bonded tertiary air duct casting material was developed by studying the damage mechanism of the tertiary air duct material. This product can be demolded, cured and baked in a very short time, which saves time for normal operation, improves economic efficiency and equipment utilization. At the same time, no harmful gases are emitted during baking, which is completely consistent with the national requirements for energy conservation, emission reduction and efficiency improvement in material development.

[0027] Therefore, the silica sol-bonded tertiary air duct casting material prepared by this invention has excellent wear resistance, erosion resistance and thermal shock resistance. It meets the long-term high-intensity working requirements in the harsh service environment of tertiary air ducts, has a long service life and long replacement cycle, reduces production costs and greatly improves production efficiency.

[0028] The features and advantages of the present invention will be described in detail through embodiments. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0030] The present invention discloses a method for preparing a silica sol-bonded tertiary air duct casting material, which specifically includes the following steps:

[0031] S1. Dry-mix fused magnesia, modified white corundum, zircon-mullite, magnesium aluminum spinel, and ceramic powder to obtain a dry material;

[0032] S2. Add the silica sol to the dry material from step S1 and mix for 1-3 minutes to obtain the intermediate material.

[0033] S3. Add the silane coupling agent to the intermediate material in step S2 and mix for 1-3 minutes to obtain the silica sol-bonded tertiary air duct casting material.

[0034] The following are the component amounts of the silica sol-bonded tertiary air duct castable: fused magnesia 20-50 wt%, modified white corundum 10-40 wt%, zirconium-mullite 10-15 wt%, magnesium aluminum spinel 10-20 wt%, ceramic powder 3-5 wt%, silica sol 5-15 wt%, and silane coupling agent 0.2-4 wt%.

[0035] Among them, the MgO content in fused magnesia is not less than 95%; in fused magnesia, the proportion of particles with a diameter of 6-10 mm is 5-20 wt%, the proportion of particles with a diameter of 3-6 mm is 35-70 wt%, and the proportion of particles with a diameter of 1-3 mm is 25-50 wt%.

[0036] In modified white fused alumina, particles with a diameter of 5-8 mm account for 5-15 wt%, particles with a diameter of 3-5 mm account for 44-65 wt%, and particles with a diameter of 1-3 mm account for 25-45 wt%.

[0037] The ZrO2 content in zirconium mullite is not less than 40 wt%, and the SiO2 content is not less than 45 wt%.

[0038] The content of AlF3 in the ceramic powder is not less than 60wt%, and the content of SiO2 is not less than 10wt%.

[0039] Example 1:

[0040] In this embodiment, the silica sol combined tertiary air duct castable uses 37wt% fused magnesia, 25wt% modified white corundum, 10wt% zirconium-mullite, 14wt% magnesium aluminum spinel, 3wt% ceramic powder, 10wt% silica sol, and 1wt% silane coupling agent.

[0041] The MgO content of the fused magnesia is 97wt%, and its specific composition is as follows: 10wt% of particles with a diameter of 6-10mm, 60wt% of particles with a diameter of 3-6mm, and 30wt% of particles with a diameter of 1-3mm.

[0042] The specific composition of modified white fused alumina is as follows: 10 wt% of particles with a particle size of 5-8 mm, 50 wt% of particles with a particle size of 3-5 mm, and 40 wt% of particles with a particle size of 1-3 mm.

[0043] The zircon-mullite contains 40 wt% ZrO2 and 45 wt% SiO2.

[0044] The porcelain powder contains 60 wt% AlF3 and 10 wt% SiO2.

[0045] Example 2:

[0046] In this embodiment, the silica sol combined tertiary air duct castable uses 31wt% fused magnesia, 26wt% modified white corundum, 11wt% zirconium-mullite, 13wt% magnesium aluminum spinel, 4wt% ceramic powder, 12wt% silica sol, and 3wt% silane coupling agent.

[0047] The MgO content of the fused magnesia is 96wt%, and its specific composition is as follows: 13wt% of particles with a diameter of 6-10mm, 50wt% of particles with a diameter of 3-6mm, and 37wt% of particles with a diameter of 1-3mm.

[0048] The specific composition of modified white fused alumina is as follows: 13wt% of particles with a particle size of 5-8mm, 60wt% of particles with a particle size of 3-5mm, and 27wt% of particles with a particle size of 1-3mm.

[0049] The zircon-mullite contains 45 wt% ZrO2 and 50 wt% SiO2.

[0050] The porcelain powder contains 70 wt% AlF3 and 15 wt% SiO2.

[0051] Example 3:

[0052] In this embodiment, the silica sol combined tertiary air duct casting material uses 36wt% fused magnesia, 22wt% modified white corundum, 12wt% zirconium-mullite, 15wt% magnesium aluminum spinel, 5wt% ceramic powder, 8wt% silica sol, and 2wt% silane coupling agent.

[0053] The MgO content of the fused magnesia is 98wt%, and its specific composition is as follows: 20wt% of particles with a diameter of 6-10mm, 40wt% of particles with a diameter of 3-6mm, and 40wt% of particles with a diameter of 1-3mm.

[0054] The specific composition of modified white fused alumina is as follows: 15wt% of particles with a particle size of 5-8mm, 55wt% of particles with a particle size of 3-5mm, and 30wt% of particles with a particle size of 1-3mm.

[0055] The zircon-mullite contains 40 wt% ZrO2 and 50 wt% SiO2.

[0056] The porcelain powder contains 75 wt% AlF3 and 13 wt% SiO2.

[0057] Example 4

[0058] In this embodiment, the silica sol combined tertiary air duct castable uses 43wt% fused magnesia, 21wt% modified white corundum, 13wt% zirconium-mullite, 11wt% magnesium aluminum spinel, 3wt% ceramic powder, 7wt% silica sol, and 2wt% silane coupling agent.

[0059] The MgO content of the fused magnesia is 99wt%, and its specific composition is as follows: 6wt% of particles with a diameter of 6-10mm, 65wt% of particles with a diameter of 3-6mm, and 29wt% of particles with a diameter of 1-3mm.

[0060] The specific composition of modified white fused alumina is as follows: 11 wt% of particles with a particle size of 5-8 mm, 45 wt% of particles with a particle size of 3-5 mm, and 44 wt% of particles with a particle size of 1-3 mm.

[0061] The zircon-mullite contains 45 wt% ZrO2 and 45 wt% SiO2.

[0062] The porcelain powder contains 80 wt% AlF3 and 16 wt% SiO2.

[0063] Example 5

[0064] In this embodiment, the silica sol combined tertiary air duct casting material uses 32wt% fused magnesia, 25wt% modified white corundum, 14wt% zirconium-mullite, 12wt% magnesium aluminum spinel, 4wt% ceramic powder, 12wt% silica sol, and 1wt% silane coupling agent.

[0065] The MgO content of the fused magnesia is 96wt%, and its specific composition is as follows: 19wt% of the particles with a diameter of 6-10mm, 54wt% of the particles with a diameter of 3-6mm, and 27wt% of the particles with a diameter of 1-3mm.

[0066] The specific composition of modified white fused alumina is as follows: 14wt% of particles with a particle size of 5-8mm, 51wt% of particles with a particle size of 3-5mm, and 35wt% of particles with a particle size of 1-3mm.

[0067] The zircon-mullite contains 50 wt% ZrO2 and 45 wt% SiO2.

[0068] The porcelain powder contains 65 wt% AlF3 and 30 wt% SiO2.

[0069] Example 6

[0070] In this embodiment, the silica sol combined tertiary air duct casting material uses 20wt% fused magnesia, 40wt% modified white corundum, 15wt% zirconium-mullite, 10wt% magnesium aluminum spinel, 5wt% ceramic powder, 8wt% silica sol, and 2wt% silane coupling agent.

[0071] The MgO content of the fused magnesia is 96wt%, and its specific composition is as follows: 19wt% of the particles with a diameter of 6-10mm, 54wt% of the particles with a diameter of 3-6mm, and 27wt% of the particles with a diameter of 1-3mm.

[0072] The specific composition of modified white fused alumina is as follows: 14wt% of particles with a particle size of 5-8mm, 51wt% of particles with a particle size of 3-5mm, and 35wt% of particles with a particle size of 1-3mm.

[0073] The zircon-mullite contains 50 wt% ZrO2 and 45 wt% SiO2.

[0074] The porcelain powder contains 65 wt% AlF3 and 30 wt% SiO2.

[0075] Example 7

[0076] In this embodiment, the silica sol combined tertiary air duct casting material uses 50wt% fused magnesia, 10wt% modified white corundum, 15wt% zirconium-mullite, 10wt% magnesium aluminum spinel, 5wt% ceramic powder, 8wt% silica sol, and 2wt% silane coupling agent.

[0077] The MgO content of the fused magnesia is 96wt%, and its specific composition is as follows: 19wt% of the particles with a diameter of 6-10mm, 54wt% of the particles with a diameter of 3-6mm, and 27wt% of the particles with a diameter of 1-3mm.

[0078] The specific composition of modified white fused alumina is as follows: 14wt% of particles with a particle size of 5-8mm, 51wt% of particles with a particle size of 3-5mm, and 35wt% of particles with a particle size of 1-3mm.

[0079] The zircon-mullite contains 50 wt% ZrO2 and 45 wt% SiO2.

[0080] The porcelain powder contains 65 wt% AlF3 and 30 wt% SiO2.

[0081] Comparative Example 1:

[0082] This comparative example of silica sol-bonded tertiary air duct castable uses 36wt% fused magnesia, 22wt% modified white corundum, 12wt% zirconium-mullite, 15wt% magnesium aluminum spinel, 5wt% ceramic powder, 8wt% silica sol, and 2wt% silane coupling agent.

[0083] The MgO content of the fused magnesia is 98wt%, and its specific composition is as follows: 30wt% of particles with a diameter of 6-10mm, 30wt% of particles with a diameter of 3-6mm, and 60wt% of particles with a diameter of 1-3mm.

[0084] The specific composition of modified white fused alumina is as follows: 20wt% of particles with a particle size of 5-8mm, 40wt% of particles with a particle size of 3-5mm, and 40wt% of particles with a particle size of 1-3mm.

[0085] The zircon-mullite contains 40 wt% ZrO2 and 50 wt% SiO2.

[0086] The porcelain powder contains 75 wt% AlF3 and 13 wt% SiO2.

[0087] Comparative Example 2:

[0088] This comparative example of calcium aluminate cement-bonded tertiary air duct castable uses 31wt% fused magnesia, 26wt% modified white corundum, 11wt% zirconium-mullite, 13wt% magnesium aluminum spinel, 4wt% ceramic powder, 12wt% calcium aluminate cement, and 3wt% silane coupling agent.

[0089] The MgO content of the fused magnesia is 96wt%, and its specific composition is as follows: 13wt% of particles with a diameter of 6-10mm, 50wt% of particles with a diameter of 3-6mm, and 37wt% of particles with a diameter of 1-3mm.

[0090] The specific composition of modified white fused alumina is as follows: 13wt% of particles with a particle size of 5-8mm, 60wt% of particles with a particle size of 3-5mm, and 27wt% of particles with a particle size of 1-3mm.

[0091] The zircon-mullite contains 45 wt% ZrO2 and 50 wt% SiO2.

[0092] The porcelain powder contains 70 wt% AlF3 and 15 wt% SiO2.

[0093] Comparative Example 3:

[0094] This comparative example of silica sol-bonded tertiary air duct castable uses 40wt% fused magnesia, 23wt% modified white corundum, 12wt% zirconium-mullite, 15wt% magnesium aluminum spinel, 8wt% silica sol, and 2wt% silane coupling agent.

[0095] The MgO content of the fused magnesia is 98wt%, and its specific composition is as follows: 20wt% of particles with a diameter of 6-10mm, 40wt% of particles with a diameter of 3-6mm, and 40wt% of particles with a diameter of 1-3mm.

[0096] The specific composition of modified white fused alumina is as follows: 15wt% of particles with a particle size of 5-8mm, 55wt% of particles with a particle size of 3-5mm, and 30wt% of particles with a particle size of 1-3mm.

[0097] The zircon-mullite contains 40 wt% ZrO2 and 50 wt% SiO2.

[0098] Comparative Example 4:

[0099] In this embodiment, the silica sol combined tertiary air duct castable uses 60wt% fused magnesia, 15wt% modified white corundum, 5wt% zirconium-mullite, 10wt% magnesium aluminum spinel, 3wt% ceramic powder, 5wt% silica sol, and 2wt% silane coupling agent.

[0100] The MgO content of the fused magnesia is 99wt%, and its specific composition is as follows: 6wt% of particles with a diameter of 6-10mm, 65wt% of particles with a diameter of 3-6mm, and 29wt% of particles with a diameter of 1-3mm.

[0101] The specific composition of modified white fused alumina is as follows: 11 wt% of particles with a particle size of 5-8 mm, 45 wt% of particles with a particle size of 3-5 mm, and 44 wt% of particles with a particle size of 1-3 mm.

[0102] The zircon-mullite contains 45 wt% ZrO2 and 45 wt% SiO2.

[0103] The porcelain powder contains 80 wt% AlF3 and 16 wt% SiO2.

[0104] Comparative Example 5:

[0105] In this embodiment, the silica sol combined tertiary air duct castable uses 25wt% fused magnesia, 20wt% modified white corundum, 20wt% zirconium-mullite, 22wt% magnesium aluminum spinel, 3wt% ceramic powder, 9wt% silica sol, and 1wt% silane coupling agent.

[0106] The MgO content of the fused magnesia is 96wt%, and its specific composition is as follows: 19wt% of the particles with a diameter of 6-10mm, 54wt% of the particles with a diameter of 3-6mm, and 27wt% of the particles with a diameter of 1-3mm.

[0107] The specific composition of modified white fused alumina is as follows: 14wt% of particles with a particle size of 5-8mm, 51wt% of particles with a particle size of 3-5mm, and 35wt% of particles with a particle size of 1-3mm.

[0108] The zircon-mullite contains 50 wt% ZrO2 and 45 wt% SiO2.

[0109] The porcelain powder contains 65 wt% AlF3 and 30 wt% SiO2.

[0110] The performance of the examples and comparative examples was tested, and the test results are shown in Table 1:

[0111] Table 1 Comparison of Performance Tests between Examples and Comparative Examples

[0112]

[0113]

[0114] Compared to Comparative Example 1, Example 1 uses a more reasonable particle size distribution, and the corresponding sample has higher mechanical strength, thermal shock resistance, and wear resistance.

[0115] Example 2 uses silica sol as a binder. Compared with the calcium aluminate cement binder in Comparative Example 2, the sample has better mechanical strength, thermal shock resistance and wear resistance.

[0116] In Example 3, ceramic powder was added. Compared with Comparative Example 3 without ceramic powder, the sample had higher mechanical strength, thermal shock resistance, and wear resistance.

[0117] Example 4 uses a suitable raw material ratio, while Comparative Example 4 uses a high-quality ratio of fused magnesia (>55wt%). The sample in Example 4 has higher mechanical strength, thermal shock resistance, and wear resistance.

[0118] Example 5 uses a suitable raw material ratio, while Comparative Example 5 uses an excessively low mass ratio of fused magnesia and an excessively high mass ratio of zircon-mullite and magnesium aluminum spinel. The sample in Example 4 has higher mechanical strength, thermal shock resistance, and wear resistance.

[0119] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a silica sol-bonded tertiary air duct casting refractories, characterized in that, Specifically, it includes the following steps: Suddenly: S1. Dry-mix fused magnesia, modified white corundum, zircon-mullite, magnesium aluminum spinel, and ceramic powder to obtain... To dry materials; S2. Add the silica sol to the dry material from step S1, mix, and obtain the intermediate material; S3. Add the silane coupling agent to the intermediate material from step S2, mix, and obtain a silica sol bonded three times. Duct casting refractory; The following are the component amounts of the silica sol-bonded tertiary air duct castable: fused magnesia 20-50 wt%, modified white corundum 10-40 wt%, zirconium mullite 10-15 wt%, magnesium aluminum spinel 10-20 wt%, ceramic powder 3-5 wt%, silica sol 5-15 wt%, and silane coupling agent 0.2-4 wt%. The zirconium-mullite contains not less than 40 wt% ZrO2 and not less than 45 wt% SiO2. The ceramic powder contains no less than 60 wt% AlF3 and no less than 10 wt% SiO2. In the fused magnesia, particles with a diameter of 6-10 mm account for 5-20 wt%, and particles with a diameter of 3-6 mm account for 3-20 wt%. The proportion of particles is 35-70 wt%, and the proportion of particles with a diameter of 1-3 mm is 25-50 wt%. In the modified white fused alumina, particles with a diameter of 5-8 mm account for 5-15 wt%, and particles with a diameter of 3-5 mm account for 3-15 wt%. The proportion of particles is 44~65wt%, and the proportion of particles with a diameter of 1~3mm is 25~45wt%.

2. The preparation method of the silica sol-bonded tertiary air duct casting material as described in claim 1, characterized in that... At: The fused magnesia contains no less than 95% MgO.

3. The preparation method of the silica sol-bonded tertiary air duct casting material as described in claim 1, characterized in that... At: The mixing time in step S2 is 1-3 minutes; the mixing time in step S3 is 1-3 minutes.

4. A silica sol-bonded tertiary air duct casting material, characterized in that: The silica sol combined with the tertiary air duct casting The casting material is prepared by the method for preparing a silica sol-bonded tertiary air duct casting material as described in any one of claims 1 to 3.

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