Belt roaster burner structure and manufacturing method thereof

Abstract

The application discloses a belt roaster burner structure, which comprises a working layer and a wear-resistant layer; the working layer is formed by pouring working layer castable and has a circular ring cross section; and the wear-resistant layer is formed by pouring wear-resistant layer castable and has a circular arc cross section and is poured on the inner bottom of the working layer. The application also discloses a belt roaster adopting the belt roaster burner structure and a manufacturing method of the belt roaster burner structure. The application can tightly combine the wear-resistant layer and the working layer, and the wear-resistant layer and the working layer are integrally formed by using castable and are not easy to be damaged. In addition, the application generates less chromium oxide, and reduces environmental pollution.

Description

Technical Field

[0001] This invention relates to the field of pellet production in the steel industry, specifically to a burner structure for a belt roaster and its manufacturing method. Background Technology

[0002] A belt calciner is a device used to produce pellets. The burner section of a belt calciner can operate at temperatures up to 1500℃ and is subjected to high-speed scouring by iron dust, making it the harshest working environment and the part with the highest material requirements. Currently, all belt calciners use an annular working layer constructed from high-temperature fired chromium corundum bricks, with a layer of chromium-containing ramming material (wear-resistant layer) tamped in the most severely worn section (the bottom 120° range of the annular working layer). This structure and material have three disadvantages: 1. The bond between the ramming material and the chromium corundum is not tight enough, and the ramming material easily falls off after a period of use. 2. The chromium corundum bricks are bonded by mortar, which is relatively thin and easily damaged, and difficult to repair, resulting in a short service life. 3. The chromium corundum bricks and chromium-containing ramming material contain a large amount of Cr2O3, and the chromium oxides will seriously pollute the environment. Summary of the Invention

[0003] The main objective of this invention is to provide a burner structure for a belt roaster and its preparation method. This burner structure enables the wear-resistant layer and the working layer to be tightly bonded and not easily detached. The wear-resistant layer and the working layer are integrally molded using castable material, making them less prone to damage. This manufacturing method produces less chromium oxide, thus reducing environmental pollution.

[0004] The technical solution adopted in this invention is:

[0005] A burner structure for a belt roaster includes a working layer and a wear-resistant layer;

[0006] The working layer is formed by casting working layer castable, and its cross-section is circular.

[0007] The wear-resistant layer is cast from wear-resistant castable material and is cast at the bottom of the working layer (the wear-resistant layer is cast on the working layer and protrudes from the working layer), and its cross-section is arc-shaped.

[0008] According to the above scheme, the thickness of the wear-resistant layer is 25-35mm (i.e., the wear-resistant layer protrudes 25-35mm from the working layer) to better protect the working layer and improve the service life of the burner structure of the belt roaster.

[0009] According to the above scheme, the central angle of the wear-resistant layer is 120° to better protect the working layer and improve the service life of the burner structure of the belt roaster.

[0010] According to the above scheme, the preparation method of the wear-resistant layer castable is as follows:

[0011] 1) Add the fine powder of dense corundum, fine powder of kyanite, fine powder of silicon carbide, fine powder of silicon nitride, and fine powder of zirconium oxide to a mixer and mix them in a mass ratio of 100:5-8:30-35:15-20:2-7 to obtain a premixed fine powder.

[0012] 2) Add the dense corundum particles and the premixed fine powder from step 1) to a mixer at a mass ratio of 100:55-65 to obtain the premixed material;

[0013] 3) Add 5-7 wt% of liquid polyborosilazane and 0.5-1.5 wt% of nickel powder to the premix in step 2), and stir to obtain the wear-resistant layer casting material.

[0014] According to the above plan, in step 1), add it to the mixer and mix for 7-10 minutes;

[0015] In step 2), add to a mixer and mix for 8-12 minutes;

[0016] Stir for 5-7 minutes in step 3) to obtain the wear-resistant layer casting material for the burner nozzle of the belt roaster.

[0017] According to the above scheme, the particle size of the dense corundum powder is ≤0.076mm, and the main chemical composition and mass percentage of the dense corundum powder are: Al2O3 content is 97.68~98.32wt%, SiO2 content is <1wt%, and Fe2O3 content is <0.15wt%.

[0018] The dense corundum particles include particles with particle sizes of 5-8 mm, 3-5 mm, 1-3 mm, and 0.076-1 mm, with the following mass percentages: 25-37 wt% : 19-23 wt% : 25-29 wt% : 12-16 wt%. The main chemical composition and mass percentages of the dense corundum particles are: Al₂O₃ content 97.66-98.12 wt%, SiO₂ content <1 wt%, and Fe₂O₃ content <0.15 wt%. The density of the dense corundum particles is 3.76-3.83 g / cm³. 3 ;

[0019] The zirconium oxide powder has a particle size ≤5μm and a ZrO2 content ≥99%;

[0020] The liquid polyborosilicate has a density of 1.58-1.81 g / cm3, a molecular weight of 700-900 g / mol, and a ceramic yield of ≥75 wt% at 800℃.

[0021] The nickel powder has a particle size of ≤300nm and a nickel content of ≥99wt%.

[0022] According to the above scheme, the preparation method of the working layer castable is as follows:

[0023] Mix the following raw materials in parts by weight: 50-60 parts zirconium corundum aggregate, 20-25 parts silicon carbide, 3-5 parts kyanite fine powder, 5-10 parts α-Al2O3 micro powder, 1-3 parts silicon nitride powder, 7-9 parts zirconium corundum powder, and 6-8 parts binder; after mixing evenly, the working layer castable is obtained.

[0024] The binder comprises silica sol and nano alumina sol, which are mixed in a mass ratio of 3:2.

[0025] According to the above scheme, the zirconium-alumina aggregate comprises zirconium-alumina particles with particle sizes of 5-8 mm, 3-5 mm, 1-3 mm, and 0.076-1 mm, with the following particle size mass percentages: 22-34 wt% : 18-22 wt% : 29-33 wt% : 12-16 wt%; the zirconium-alumina powder has a particle size ≤0.076 mm; the main chemical components and mass percentages of the zirconium-alumina aggregate and zirconium-alumina powder are: Al2O3 content 68.34-72.15 wt%, ZrO2 content 24.27-30.21 wt%, SiO2 content <0.5 wt%, Fe2O3 content <0.2 wt%; the density of the zirconium-alumina particles is 3.94-4.10 g / cm³. 3 ;

[0026] The silicon carbide has a particle size of 0.02–1 mm and a SiC content of ≥98 wt%.

[0027] The kyanite powder has a particle size of 60–80 μm and a density of 3.50–3.58 g / cm³. 3 The kyanite fine powder is formulated as follows by mass percentage: Al2O3:SiO2 = 60-62 wt% : 35-36 wt%.

[0028] The silica sol is JN-40 type silica sol; the silica sol meets the following requirements: SiO2 content ≥ 40wt%, R2O ≤ 0.4wt%;

[0029] The nano-alumina sol is formulated as follows by mass percentage: Al2O3 content ≥ 35wt%, R2O ≤ 0.17wt%;

[0030] The particle size of the α-Al2O3 micro powder is ≤0.044mm, and the Al2O3 content of the α-Al2O3 micro powder is ≥98wt%.

[0031] The silicon nitride powder has a particle size ≤45μm and a Si3N4 content >98wt%.

[0032] The present invention also provides a belt roaster employing the above-described belt roaster burner structure.

[0033] This invention also provides a method for manufacturing the above-mentioned belt roaster burner structure:

[0034] 1) Prepare the working layer castable and cast the working layer using the working layer castable;

[0035] 2) Prepare the wear-resistant layer casting material. Pour the wear-resistant layer casting material onto the working layer through the formwork. Use a vibrator to vibrate and compact the wear-resistant layer casting material to obtain the wear-resistant layer.

[0036] The beneficial effects of this invention are as follows:

[0037] The wear-resistant layer is poured into the bottom of the working layer, so that the wear-resistant layer is tightly bonded to the working layer and is not easy to fall off.

[0038] The wear-resistant layer and the working layer are integrally molded with castable material, which is not easily damaged, easy to maintain and replace, and improves the service life of the burner;

[0039] The method for preparing the working layer castable and the wear-resistant layer castable is simple and produces less chromium oxide, thus reducing environmental pollution and making it safe and environmentally friendly.

[0040] The burner structure adopts an integral casting method for the working layer and the wear-resistant layer, which is convenient and quick to construct and easy to maintain later. In addition, the integral casting method eliminates the problem of the refractory mortar used for masonry becoming a weak point in the material during the use of refractory bricks, thus affecting the service life of the material.

[0041] The use of zirconium corundum with excellent corrosion resistance and the addition of zirconium oxide to dense corundum are used to replace the large amount of chromium-containing refractory bricks and chromium-containing castables currently used in the burner part of the belt calciner, thus eliminating the environmental pollution caused by chromium oxides.

[0042] The wear-resistant layer uses liquid polyborosilazane as a binder, and the addition of nickel powder results in a high ceramic yield under high-temperature operating conditions. The ceramic bonding improves the high-temperature performance and wear resistance of the material.

[0043] The working layer uses silica sol and nano-alumina sol as binders, which, compared to the traditional chromium-containing castables that use calcium aluminate cement, eliminates the need for Ca2+. 2+ The introduction of [something] leads to a decrease in the high-temperature performance of the material. At the same time, the material performance is improved by in-situ generation of mullite from SiO2 and nano-Al2O3 in highly active silica sol, which makes the wear-resistant layer and the working layer tightly bonded and not easy to fall off. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a structural diagram of the burner structure of a belt roaster;

[0046] Figure 2 This is a three-dimensional structural diagram of the burner structure of a belt roaster;

[0047] In the diagram: 1. Working layer; 2. Wear-resistant layer. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0049] Example 1

[0050] See Figure 1 , Figure 2 A method for manufacturing a burner structure for a belt roaster:

[0051] 1) Prepare the working layer castable and cast the working layer 1 using the working layer castable;

[0052] 2) Prepare the wear-resistant layer casting material. Pour the wear-resistant layer casting material into the bottom of the inner wall of the working layer 1 through the formwork. Use a vibrator to vibrate and compact the wear-resistant layer casting material to obtain the wear-resistant layer 2.

[0053] Example 2

[0054] See Figure 1 and Figure 2 A belt roaster burner structure manufactured using the manufacturing method of the belt roaster burner structure in Example 1 includes a working layer 1 and a wear-resistant layer 2.

[0055] The working layer 1 is formed by casting the working layer castable, and its cross-section is circular.

[0056] The wear-resistant layer 2 is formed by casting wear-resistant layer castable, and the wear-resistant layer 2 is cast at the bottom of the inner wall of the working layer 1 (i.e., the wear-resistant layer 2 protrudes from the working layer 1). Its cross-section is arc-shaped, and the central angle of the arc is 120°. The thickness of the wear-resistant layer 2 is 34mm (i.e., the wear-resistant layer protrudes from the working layer by 34mm).

[0057] In this embodiment, the preparation method of the wear-resistant layer castable is as follows:

[0058] 1) Add the fine powders of dense corundum, fine kyanite, fine silicon carbide, fine silicon nitride, and zirconium oxide to a mixer in a mass ratio of 100:7:32:17:5 and mix for 8 minutes to obtain a premixed fine powder.

[0059] 2) Add the dense corundum particles and the premixed fine powder from step 1) to a mixer at a mass ratio of 100:60 and mix for 10 minutes to obtain the premixed material;

[0060] 3) Add 7 wt% liquid polyborosilazane and 1 wt% nickel powder to the premix from step 2), and stir for 6 minutes to obtain the wear-resistant layer castable. The obtained wear-resistant layer castable was tested and found to have a bulk density of 3.21 g / cm³ after firing at 1500℃ for 3 hours. 3 The cold compressive strength after firing at 1500℃ for 3 hours was 119.32 MPa, and the wear amount in the room temperature abrasion resistance test after firing at 1500℃ for 3 hours was 2.4 cm. 3 The erosion index of the static crucible method slag resistance test (using iron ore as the erosion medium) at 1400℃ for 3 hours was 2.9%.

[0061] Specifically, the particle size of the dense corundum powder is ≤0.076mm, and the main chemical components and mass percentages of the dense corundum powder are: Al2O3 content is 97.68~98.32wt%, SiO2 content is <1wt%, and Fe2O3 content is <0.15wt%.

[0062] The dense corundum particles include particles with sizes of 5–8 mm, 3–5 mm, 1–3 mm, and 0.076–1 mm, with the following mass percentages: 25–37 wt% : 19–23 wt% : 25–29 wt% : 12–16 wt%. The main chemical composition and mass percentages of the dense corundum particles are: Al₂O₃ content 97.66–98.12 wt%, SiO₂ content <1 wt%, and Fe₂O₃ content <0.15 wt%. The density of the dense corundum particles is 3.76–3.83 g / cm³. 3 ;

[0063] Zirconia powder has a particle size ≤5μm and a ZrO2 content ≥99%;

[0064] The density of liquid polyborosilazane is 1.58-1.81 g / cm³. 3 The molecular weight is 700-900 g / mol, and the ceramic yield at 800℃ is ≥75 wt%.

[0065] The nickel powder has a particle size ≤300nm and a nickel content ≥99wt%.

[0066] In this embodiment, the preparation method of the working layer castable is as follows:

[0067] The following raw materials are mixed in the following proportions by weight: 55 parts zirconium corundum aggregate, 20 parts silicon carbide, 4 parts kyanite fine powder, 5 parts α-Al2O3 micro powder, 3 parts silicon nitride powder, 7 parts zirconium corundum powder, and 6 parts binder; after mixing evenly, the working layer casting refractory is obtained.

[0068] The binder comprises silica sol and nano-alumina sol, and the silica sol and nano-alumina sol are mixed in a 3:2 ratio by mass.

[0069] Specifically, the zirconium-alumina aggregate comprises zirconium-alumina particles with particle sizes of 5-8 mm, 3-5 mm, 1-3 mm, and 0.076-1 mm, with the following mass percentages for each particle size: 22-34 wt% : 18-22 wt% : 29-33 wt% : 12-16 wt%; the zirconium-alumina powder has a particle size ≤0.076 mm, and the main chemical components and mass percentages of the zirconium-alumina aggregate and powder are: Al2O3 content 68.34-72.15 wt%, ZrO2 content 24.27-30.21 wt%, SiO2 content <0.5 wt%, and Fe2O3 content <0.2 wt%; the density of the zirconium-alumina particles is 3.94-4.10 g / cm³. 3 ;

[0070] The particle size of silicon carbide is 0.02-1 mm, and its SiC content is ≥98 wt%.

[0071] The fine kyanite powder has a particle size of 60–80 μm and a density of 3.50–3.58 g / cm³. 3 The kyanite fine powder is formulated as follows by mass percentage: Al2O3:SiO2 = 60-62 wt% : 35-36 wt%.

[0072] The silica sol is JN-40 type silica sol; the silica sol meets the following requirements: SiO2 content ≥ 40wt%, R2O ≤ 0.4wt%;

[0073] The nano-alumina sol is formulated as follows by mass percentage: Al2O3 content ≥35wt%, R2O ≤0.17wt%;

[0074] The particle size of the α-Al2O3 micro powder is ≤0.044mm, and the Al2O3 content of the α-Al2O3 micro powder is ≥98wt%.

[0075] The particle size of the silicon nitride powder is ≤45μm, and its Si3N4 content is >98wt%.

[0076] Example 3

[0077] See Figure 1 and Figure 2 A belt roaster burner structure manufactured using the manufacturing method of the belt roaster burner structure in Example 1 includes a working layer 1 and a wear-resistant layer 2.

[0078] The working layer 1 is formed by casting the working layer castable, and its cross-section is circular.

[0079] The wear-resistant layer 2 is formed by casting wear-resistant layer castable, and the wear-resistant layer 2 is cast at the bottom of the inner wall of the working layer 1 (i.e., the wear-resistant layer 2 protrudes from the working layer 1). Its cross-section is arc-shaped, and the central angle of the arc is 120°. The thickness of the wear-resistant layer 2 is 34mm (i.e., the wear-resistant layer protrudes from the working layer by 34mm).

[0080] In this embodiment, the preparation method of the wear-resistant layer castable is as follows:

[0081] 1) Add the fine powders of dense corundum, fine kyanite, fine silicon carbide, fine silicon nitride, and zirconium oxide to a mixer at a mass ratio of 100:8:35:15:2 and mix for 10 minutes to obtain a premixed fine powder.

[0082] 2) Add the dense corundum particles and the premixed fine powder from step 1) to a mixer at a mass ratio of 100:65 and mix for 10 minutes to obtain the premix.

[0083] 3) Add 7 wt% liquid polyborosilazane and 1.5 wt% nickel powder to the premix from step 2), and stir for 7 minutes to obtain the wear-resistant layer castable. The obtained wear-resistant layer castable was tested and found to have a bulk density of 3.23 g / cm³ after firing at 1500℃ for 3 hours. 3 The cold compressive strength after firing at 1500℃ for 3 hours was 124.58 MPa, and the wear amount in the room temperature abrasion resistance test after firing at 1500℃ for 3 hours was 2.2 cm. 3 The erosion index of the static crucible method slag resistance test (using iron ore as the erosion medium) at 1400℃ for 3h was 3.4%.

[0084] Specifically, the particle size of the dense corundum powder is ≤0.076mm, and the main chemical components and mass percentages of the dense corundum powder are: Al2O3 content is 97.68~98.32wt%, SiO2 content is <1wt%, and Fe2O3 content is <0.15wt%.

[0085] The dense corundum particles include particles with sizes of 5–8 mm, 3–5 mm, 1–3 mm, and 0.076–1 mm, with the following mass percentages: 25–37 wt% : 19–23 wt% : 25–29 wt% : 12–16 wt%. The main chemical composition and mass percentages of the dense corundum particles are: Al₂O₃ content 97.66–98.12 wt%, SiO₂ content <1 wt%, and Fe₂O₃ content <0.15 wt%. The density of the dense corundum particles is 3.76–3.83 g / cm³. 3 ;

[0086] Zirconia powder has a particle size ≤5μm and a ZrO2 content ≥99%;

[0087] The density of liquid polyborosilazane is 1.58-1.81 g / cm³. 3 The molecular weight is 700-900 g / mol, and the ceramic yield at 800℃ is ≥75 wt%.

[0088] The nickel powder has a particle size ≤300nm and a nickel content ≥99wt%.

[0089] In this embodiment, the preparation method of the working layer castable is as follows:

[0090] The following raw materials are mixed in the following proportions by weight: 54 parts zirconium corundum aggregate, 20 parts silicon carbide, 3 parts kyanite fine powder, 5 parts α-Al2O3 micro powder, 1 part silicon nitride powder, 9 parts zirconium corundum powder, and 8 parts binder; after mixing evenly, the working layer casting refractory is obtained.

[0091] The binder comprises silica sol and nano-alumina sol, and the silica sol and nano-alumina sol are mixed in a 3:2 ratio by mass.

[0092] Specifically, the zirconium-alumina aggregate comprises zirconium-alumina particles with particle sizes of 5-8 mm, 3-5 mm, 1-3 mm, and 0.076-1 mm, with the following mass percentages for each particle size: 22-34 wt% : 18-22 wt% : 29-33 wt% : 12-16 wt%; the zirconium-alumina powder has a particle size ≤0.076 mm, and the main chemical components and mass percentages of the zirconium-alumina aggregate and powder are: Al2O3 content 68.34-72.15 wt%, ZrO2 content 24.27-30.21 wt%, SiO2 content <0.5 wt%, and Fe2O3 content <0.2 wt%; the density of the zirconium-alumina particles is 3.94-4.10 g / cm³. 3 ;

[0093] The particle size of silicon carbide is 0.02-1 mm, and its SiC content is ≥98 wt%.

[0094] The fine kyanite powder has a particle size of 60–80 μm and a density of 3.50–3.58 g / cm³. 3 The kyanite fine powder is formulated as follows by mass percentage: Al2O3:SiO2 = 60-62 wt% : 35-36 wt%.

[0095] The silica sol is JN-40 type silica sol; the silica sol meets the following requirements: SiO2 content ≥ 40wt%, R2O ≤ 0.4wt%;

[0096] The nano-alumina sol is formulated as follows by mass percentage: Al2O3 content ≥35wt%, R2O ≤0.17wt%;

[0097] The particle size of the α-Al2O3 micro powder is ≤0.044mm, and the Al2O3 content of the α-Al2O3 micro powder is ≥98wt%.

[0098] The particle size of the silicon nitride powder is ≤45μm, and its Si3N4 content is >98wt%.

[0099] Example 4

[0100] A belt roaster that adopts the burner structure of the belt roaster in Example 2.

[0101] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A burner structure for a belt roaster, characterized in that: Includes the working layer and the wear-resistant layer; The working layer is formed by casting working layer castable, and its cross-section is circular. The preparation method of the working layer castable is as follows: Mix the following raw materials in parts by weight: 50-60 parts zirconium corundum aggregate, 20-25 parts silicon carbide, 3-5 parts kyanite fine powder, 5-10 parts α-Al2O3 micro powder, 1-3 parts silicon nitride powder, 7-9 parts zirconium corundum powder, and 6-8 parts binder; after mixing evenly, the working layer castable is obtained. The binder comprises silica sol and nano alumina sol, wherein the silica sol and nano alumina sol are mixed in a mass ratio of 3:

2. The wear-resistant layer is cast from wear-resistant castable material and is cast at the bottom of the working layer, with a circular arc cross-section. The preparation method of the wear-resistant layer castable is as follows: 1) Add the fine powders of dense corundum, fine kyanite, fine silicon carbide, fine silicon nitride, and fine zirconium oxide to a mixer and mix them in a mass ratio of 100:5-8:30-35:15-20:2-7 to obtain a premixed fine powder. 2) Add the dense corundum particles and the premixed fine powder from step 1) to a mixer at a mass ratio of 100:55-65 to obtain the premixed material; 3) Add 5-7 wt% of liquid polyborosilicate and 0.5-1.5 wt% of nickel powder to the premix in step 2), and stir to obtain the wear-resistant layer casting material.

2. The burner structure of the belt roaster according to claim 1, characterized in that: The thickness of the wear-resistant layer is 25-35mm.

3. The burner structure of the belt roaster according to claim 1 or 2, characterized in that: The central angle of the wear-resistant layer is 120°.

4. The burner structure of the belt roaster according to claim 1, characterized in that: In step 1), add to a mixer and mix for 7-10 minutes; In step 2), add to a mixer and mix for 8-12 minutes; Stir for 5-7 minutes in step 3) to obtain the wear-resistant layer casting material for the burner of the belt roaster.

5. The burner structure of the belt roaster according to claim 1, characterized in that: The dense corundum powder has a particle size ≤0.076mm, and its main chemical composition and mass percentage are as follows: Al2O3 content 97.68~98.32wt%, SiO2 content <1wt%, Fe2O3 content <0.15wt%. The dense corundum particles include particles with sizes of 5-8 mm, 3-5 mm, 1-3 mm, and 0.076-1 mm, with the following mass percentages of particle size: 25-37 wt% : 19-23 wt% : 25-29 wt% : 12-16 wt%. The main chemical composition and mass percentages of the dense corundum particles are: Al₂O₃ content 97.66-98.12 wt%, SiO₂ content < 1 wt%, and Fe₂O₃ content < 0.15 wt%. The density of the dense corundum particles is 3.76-3.83 g / cm³. 3 ; The zirconium oxide powder has a particle size ≤5μm and a ZrO2 content ≥99%; The density of the liquid polyborosilazane is 1.58-1.81 g / cm³. 3 Molecular weight is 700-900 g / mol, ceramic yield at 800℃ is ≥75 wt%; The nickel powder has a particle size of ≤300nm and a nickel content of ≥99wt%.

6. The burner structure of the belt roaster according to claim 1, characterized in that: The zirconium-alumina aggregate comprises zirconium-alumina particles with particle sizes of 5-8 mm, 3-5 mm, 1-3 mm, and 0.076-1 mm, with the following mass percentages of particle size: 22-34 wt% : 18-22 wt% : 29-33 wt% : 12-16 wt%. The zirconium-alumina powder has a particle size ≤0.076 mm. The main chemical components and mass percentages of the zirconium-alumina aggregate and powder are: Al₂O₃ content 68.34-72.15 wt%, ZrO₂ content 24.27-30.21 wt%, SiO₂ content <0.5 wt%, and Fe₂O₃ content <0.2 wt%. The density of the zirconium-alumina particles is 3.94-4.10 g / cm³. 3 ; The silicon carbide has a particle size of 0.02~1mm and a SiC content of ≥98wt%. The kyanite powder has a particle size of 60-80 μm and a density of 3.50-3.58 g / cm³. 3 The kyanite powder is formulated as follows by mass percentage: Al2O3:SiO2 = 60~62wt%: 35~36wt%; The silica sol is JN-40 type silica sol; the silica sol meets the following requirements: SiO2 content ≥ 40wt%, R2O ≤ 0.4wt%; The nano-alumina sol is formulated as follows by mass percentage: Al2O3 content ≥ 35wt%, R2O ≤ 0.17wt%; The α-Al₂O₃ micro powder has a particle size ≤ 0.044 mm and an Al₂O₃ content ≥ 98 wt%. The silicon nitride powder has a particle size of ≤45μm and a Si3N4 content of >98wt%.

7. A belt roasting machine, characterized in that: The belt roaster adopts the burner structure of any one of claims 1-6.

8. A method for manufacturing the burner structure of the belt roaster according to any one of claims 1-6: 1) Prepare the working layer castable and cast the working layer using the working layer castable; 2) Prepare the wear-resistant layer casting material. Pour the wear-resistant layer casting material onto the working layer through the formwork. Use a vibrator to vibrate and compact the wear-resistant layer casting material to obtain the wear-resistant layer.

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